One Way to Quickly Destroy a Two Stroke Engine

How using the wrong type is piston pin clip and or installing it incorrectly can cause it to destroy your 2 stroke engine.
Video demonstrates how to inspect and safely fit and remove the piston pin circlip / snap ring.

[@whiskeytangofoxtrot9403]

It's aggravating seeing people act foolish on youtube and get paid well while we have you actually trying to educate people and can't catch a break. Thank you and Keep up the good work as long as you can.

[@AuMechanic]

Thanks for the comment. I do need to try and make the videos a bit more interesting from a visual perspective since YT is a video platform after all and I've relied a lot on the white board instructional's a bit too much. That is partly why I decided to buy an engine and do a bit of hands on as well that makes it a bit less boring to watch. While doing more generalised stuff and maybe some build projects would get more views and such there is also an abundance of channels that do that already and its not particularly instructive or educational even if it is entertaining. Its a fine line between education and "infotainment" and I need to work on the content and try to tune the balance more to make the videos more appealing but not loose the technical detail.

[@johnvanberrgem286]

I will keep watching.

[@frankcrawford416]

@@AuMechanic You are doing a great job and it may take awhile but your membership will grow. People tend to know great content. Thanks.

[@SDsailor7]

@@AuMechanic The rings on my new piston have a letter on them does the letter face towards the top of the piston or the bottom? My old piston rings did not have any markings on them. Thank you

[@AuMechanic]

@@SDsailor7 Any marks on the ring usually goes to the top.

[@thomashowlett8295]

I did not know this. I had never really considered the orientation of the circlip before installing them, even though I've been working on two-stroke engines for many years. Thank you, I'll be more careful in the future!

[@AuMechanic]

Hope that saves at least a few people from falling victim to piston clip damage..

[@brendancheyne3315]

Thank you very very much for helping us to get a better understanding of why we should or should not do things which may without seeking good sound advice such as yours seem the appropriate way to go. I for 1 will be watching and looking forward to many more instalments from you!

[@killuminatii1]

Never noticed this. Always installed with a pliers and never noticed the ears. Never destroyed a engine but this video gives golden tips.

[@AuMechanic]

Odds are it will not happen for most, the problem is that if the clip does fail as it does sometime then it makes an expensive mess, at which rate if doing a rebuild it is a small thing to sort out to ensure it never fails.

[@paulchambers969]

Can these clips be replaced with proper circlips or.are they just as safe if installed correctly. I just purchased a 45 cc Rovan engine in seperate peices.

[@teenice894]

Watched this after fighting putting in my 1st surclip.. i definitely bent the ears.... thanks buddy

[@bobgreene5460]

This was the best video I've seen on the G-clip. The 66cc engine gains power with porting as I have learned. Experimenting the Rookie way., I try to sneak up on how far is too far when opening the ports. Tearing top ends up just on this topic .

[@AuMechanic]

Thanks for the comment. Thing with porting to keep in mind that going big on the exhaust timing is not so bad so long as you don't go too high in transfers and leave it with a short blow down time which can cause a fair drop in power.

[@dakotaberry2483]

Velcro strap worked flawlessly, thx dude

[@toolspayless]

Good tip, I have not seen any other videos explain this with as much detail? The younger generation should watch this?

[@captaincam07]

This is very helpful and I wish I seen it sooner. Last year I bought one of these engines from bike berry and I was new to this so when I installed it I pushed the bent pin in. Basically around 3 months later i went to start up my engine and when I dumped the clutch my bike wheel skirted against the ground, and upon inspecting it my piston clip was gone. I tried 3 different times to fix it and i eventually gave up and scraped it. Currently I’m gettin a new kit and the engine will be assembled already so I won’t have to worry about that happening again.

[@cgriebel1]

Thanks for the pro tip. I've never looked for this and sometimes it's the small oversights that can ruin a job.

[@timdryden3778]

An excellent point, I never considered this, and was unaware of the radius's function. THANKS

[@AuMechanic]

Cheers Tim.

[@pazuzukomardukkkjoiimmimmi3604]

Very helpful ty

[@outbackenduro7418]

Thanks for this in depth video. Isn't it amazing what detail can do for your outcome. In this case the difference between a disaster outcome and one of many trouble free hours.

[@AuMechanic]

Yes, it also is one reason why attention to detail is important doing engine rebuilds as the whole thing can come undone due to oversight of just a simple part worth a few dollars.

[@honingholes7026]

I fitted some yesterday and I was lucky, I noticed the bend in the ring and faced it outward, I thought it was like that to make it easier to fit.

[@selprocr]

EXCELENT VIDEO, EXCELENT EXPLANATION, GREAT, GREAT, GREAT..... I was a victim of that specific damadge in my 52cc engine. The machine had problems 6 months after purchase. That clip was installed from factory and when I dissasembled the engine, liittle part of that ear of clip broke and scratched all cylinder and piston. Fortunatlely I saw this video before reasembly all. Thanks...

[@AuMechanic]

Its a small thing but causes large damage. And being a less common failure it is often overlooked, it is not till you start doing engines a lot you start to see a trend with piston clips that leads you to think that piston clips with ears are not a good idea in 2 strokes. Most 2 stroke engine manufacturers seem wise to it and use earless clips but not all such as the cheap knock off engines like the one I use in the video.

[@SDsailor7]

My moped has the other type of circlips. They are the ones that have the solid (closed) holes so they are a little bit harder to get ahold of with regular needle nose pliers fortunately i have a tool made for those circlips.

[@louiemilton883]

I thank you very much for this interesting fact bet I been fitting them wrong way for years. Thanks mate top bloke

[@DaleMcKenna]

Great vid Dave, very helpful with my 66cc motorized bicycle engine. I've had clip failure twice (luckily without harm to the conrod bearing). I'll share this vid across a few FB groups as I'm sure the information will be valued.

[@AuMechanic]

Thank's Dale, sharing much appreciated.

[@markmckenzie3072]

That's brilliant. Cheers. You've saved my saw.

[@AuMechanic]

Glad to help

[@vtcycle]

I'm rebuilding my Jonsered chainsaw, good thing I saw this. Thanks. Very well done.

[@AuMechanic]

Thank's for the comment

[@الشيخذيب-ض1ش]

Thank you.. I've learned how to prove this hard part.

[@keithscott9774]

Thanks very much AuMechanic. I'm looking at buying and rebuilding an outboard motor, so really good to know about this.

[@blainemacdonald6929]

On another note the circlip gap should be at the top or bottom on high reving engines. The rapid change in direction can cause them to compress and fall out

[@johnvanberrgem286]

True.

[@pbysome]

Trying to convince people of this is difficult.

[@volkusa5808]

The clips without the tab can be next to impossible to remove and you can easily damage the piston trying to remove them..

[@AuMechanic]

Yes they are if you don't take care and use a very sharp pick to get them out. Likewise you can do a lot worse if you are not careful rebuilding any engine assembly. Its best to grind a slot to remove them when fitting them in the first place. Conversely if one of the clips come out due to the ear as the video explains or an ear gets sawn off as they do sometimes you stand to damage a lot more than just a scratch on a piston. If you are lucky you will trash the piston, if not so lucky you will trash the piston and the bore and the big end a main bearings when bits of the piston end up in the crankcase and smeared on the bearing surfaces. You only need to read the comments here to see how badly it can end.

[@Adam-xs3ng]

Nice installation tips buddy.

[@gunthertooty6594]

Wow I never knew about this I'll sure keep this in mind for now on thanks another for the info

[@mackenziesibley7025]

We usually clip the ear off in chainsaw builds

[@scroogehowsshehandle]

Very interesting makes perfect sense. Thank you.

[@liamwilliams7782]

I just done a full rebuild on an aprilia sx 50 new racing crank upgraded bearings ect come to buying a 88cc malossi big bore kit £230 & even there piston clips have ears for something that's all about racing ect I think if it was much hazard for the 20/30p it probably cost them surely they would change them?? I'm all about restoring & making absolute beasts out of a bike specially two stokes and must say I never seen one without the ears & could imagine with the flex of it the pin would have to pop the clip out before the ear would snap as 3/4 of the clip it sits on is clipped in so I think this would be VERY rare in all fairness but it still does make sense to put clips in without the ear but if it comes out it's going to destroy your engine anyway but The pin doesn't just push on ear as the clip would never sit flush so it pushes on the hole clip and the pins always have a hole in for lube reasons so there would be more pressure on the outter of the clip only if like you claim there's no bend onwards on the ear & I bet if you check 9/10 are slightly bent so not claiming what your saying is wrong though your very right but chances of this happening probably the same as a Cyclops horse lol brilliant informational video though keep them coming ,👍👍 top man

[@bemisfamily06]

Great video, thanks for taking the time to explain!

[@PWRREPAIRSLIMITED]

You are correct sir. Ive just done a huski k970 concrete saw and the clips are bent outwards to prevent this. I have done the same engine before and the clip broke because I didnt know this issue and destroyed the piston. Even the factory repair manual doesnt say anything about this. So thanks for this information

[@AuMechanic]

Thanks for the comment.

[@pauldowsett9673]

Excellent tips wish I had come across you first saved me heaps of time trying different methods

[@AuMechanic]

Thanks for the comment

[@SDsailor7]

@@AuMechanic In reply to your last response to me, the moped i have is a Peugeot 103 and yes all the piston kits they have advertised do not come with the rings assembled on the piston maybe mine came like that because they came in a plastic round case that is a little bigger than the piston so they fitted the piston with the rings installed and the pin and circlips inside the piston cavity. Another thing i discovered when i measured the ring gap is that the to ring is out of specs it measures .019thousands of an inch when it should be .006 thousands. I know that the rings expand with heat but not sure if it will hold compression? the max gap should be .012 thou. Maybe i should return the piston to the place i bought it or can i use it? and if i do should i use as the top ring or bottom? the bottom is in specs at .006 What do you suggest? Thank you

[@AuMechanic]

@@SDsailor7 Never had ri8ngs come fitted to a piston new. The ring end gap is relative to the bore and if that is correct then it could be a ring issue. id contact the sellers and ask them to supply a new ring that is within spec.

[@naturechanel209]

I had this happen on my 87 puch moped I put a 70cc big bore kit on it and didnt know these were trash clips. Now I just ordered parts and now I gotta order a crank case gasket cuz i know that piece of broken clip didnt come out my exhaust and it had to go somewhere when i lost all compression. Thank you for this video probly saved me another rebuild

[@AuMechanic]

Yes it'd be a good idea to split the casing and make sure everything is ok on the bottom end.

[@naturechanel209]

@@AuMechanic it was a single piston ring and I think it got coughed out the exhaust I herd somthing fly out I just never found it it was a main road to but I'd need to buy more tools I really dont have the money to spend on like and pnematic screw breaker so I can loosen the crank case I've turnend it over so many times with a drill I dont think it matters if the damage is done I'll rebuild it all the way and buy a new racing crack and bearings and seal and get a better two wiring piston for it I hope it didnt. If it did I'm gunna have to buy alot more stuff hahahaha just another reason to get another better head lol I reall hope it didnt tho cuz i cant afford that I drained the oil and I'm gunna drain it again in the morning and see if I can shake it aroun surprisingly no meteal or metal shavings in the oil so I'm hoping its not just pat of a gear now if it is let's hope it stays there

[@naturechanel209]

@@AuMechanic idk you tell Mr if it's worth it j could breake the old ass screws there from 1987 and then I gotta get some gasget sealer and hope I seal it up good enough and scrape everything clean and tighten it all back down but I need a impact screw breaker to do the case it's kinda out my range

[@naturechanel209]

@@AuMechanic it's also a piston port intake 2 stroke I may as drop the engine and do it if I wanna daily drive it. I've never split an engine before so I'm kinda nervous maybe I'll just open the side up and see if I can spot any damage with a good light and camera

[@AuMechanic]

@@naturechanel209 If you don't want to split the casings then just inspect the big end bearing for any signs is debris like small specks of aluminium and give the bottom end a good rinse out with some pre mix fuel.

[@jstek9133]

Good to know. Most of the things you said not to do, is what I did.

[@weldmachine]

The only way viewers can support your channel without Patreon. Is watch the advertisements. ( in length ) Which unfortunately people Hate to do. I do watch the advertisements for this reason. A lot of people don,t know this and hit the Skip button ASAP. Thanks for the video. Peter.

[@AuMechanic]

That's ok, I get a few google bucks now and then. Ive got a paypal on the software site I should probably put it on YT pages too,

[@shinigami117s8]

Im glad im not the only one! found this out the hard way when i was 15.

[@AuMechanic]

It is something that is not a common failure point. To owners who rebuild their engines most will likely never see it in their life time. But rebuilding engines as a full time mechanic it is something that becomes evident after a few years, seeing a clip fail every now and then over hundreds of engines. And being something that is so easily resolved by using an earless clip and cheap I believe it is worth doing, even if the clip failure is not a common fault, if it does fail the damage is expensive.

[@mrrcadventurese8461]

thanks for the video I have 2 1/5 scale 2 stroke gas rc trucks 29c 45cc these tips are good to know

[@AuMechanic]

Glad you found it useful.

[@Paul_Gale]

thanks for the video! i'm putting a window piston and reed valve on soon and I appreciate the info just subbed

[@AuMechanic]

Thank you.

[@schelmean16]

None of polini or malossi tuning zylinders(60-70ccm) i bought had this lil notch in the piston The polini actually came wit 2 ears per criclip it was the heaven to install and it didnt pop out yet and ive been riding 4000+km

[@AuMechanic]

No surprises there, I've seen a few 2 stroke engines with no slot in the piston and in some cases no slot or ears on the clip which makes getting the clip out a real pain. As for clips with ears not coming out, if you are lucky they wont but if you spend time engine building as a working mechanic its only a matter of time before you see engines with clips that have come out and got chopped in the transfer ports. Fitting the clip with long nose pliers increases the chance greatly an ear will get bent inward and the chances the clip will come out when its running.. Only 100% way to guarantees the clip wont come out ever is to use ones without the ears.

[@TheRober806]

Thanks for the very educational video 🙂👍

[@darrenpickens7147]

Never had a problem with any 2-stroke engines I have done using pliers to install the circlips. However I do see your point. Right now I'm working on a husqvarna 55 chainsaw. I have got an aftermarket piston kit, and the piston(has 10mm wrist pin) DOES NOT have that notch. You are pretty much forced using pliers to install the circlip or spend big money in getting a specialty tool to do the job. Imagine trying to remove a circlip without that "ear" from a piston with no notch.

[@AuMechanic]

Yes I have had pistons without the notch, getting the earless clip in is easy enough, I use a pick tool to lever the clip in to the slot either way even if the clip has ears on it. But getting it back out is a hassle and requires a pick tool with a nice sharp tip and can leave a bit of a mark in the clip groove too. But then in most cases you wont need to remove the piston off the rod unless you are going to replace it in which case marking up the clip groove is not an issue since the piston isn't being re-used. It is possible that was the logic manufacturers use when making notch less 2 stroke pistons.

[@Littleevil9975]

Great video

[@bhula40250]

I've used Ez clips for years with no issues, like any clip they need to be installed correctly and facing the top of the piston head, Vertex Circlips - 72060K

[@AuMechanic]

So far so good then and chances are you wont suffer the same fate as so many here in the comment section have using clips with ears in a 2 stroke.

[@abikelife1481]

The wrist pin is going to push on those too, and after while that ear gets weakened and breaks. I went with some wiseco 10 clips, no ear to worry about and they're good and heavy duty.

[@AuMechanic]

Yes the pin twisting motion can against the clip ear can saw off the ear after a while. I have some images I will post soon showing one nearly sawn off in a Husqvarna chainsaw engine.

[@RandomBradCreator]

Ok so i just figured out why or maybe the cause of An old 80's Victa 2 stroke Charger i was given is Dead , i opened up the sucker and that circlip was in the port , The Gouge in the Bore is WoW 😂 new piston and rings dead , i wonder why the fella looked at me strange when i said i'll pull it down , see what you've done to it lol , ive only just opened up and thought how the hell did that happen , Now i know Cheers for this Subbed

[@AuMechanic]

Surprising how much damage such a small cheap part can do eh. And note to anyone still skeptical about this video as there has been, let this comment be another example to show that while it may never happen and it is not all that common, if it happens to your engine you will wish you'd not ignored the advice. PS thanks for the sub.

[@julianlaustsen1991]

I had circlips like this on my suzuki ts50x for 3 years. had alot of miles on it, never any problem.

[@AuMechanic]

Glad to hear it As mentioned most people will never have any trouble with them. But as you can see in the comments section here that many have, and it nearly always ends badly if you do have one come out in a 2 stroke.

[@johnpower8356]

I agree with this, but the G shaped circ clips are so much easier than the C shaped ones. I use what ever comes in the piston kit. When it's the G shaped I put the bend out away from the pin. Honestly it doesn't seem to matter, none of mine have come out, altho I've seen it. I do a lot of 70 cc bbk's and I see a lot of problems but not this one. Mostly heat, jetting, and when you don't deburr and break all the sharp edges on your new piston and cylinder then clean and blow off.

[@AuMechanic]

As long as you put the bend outwards that will help. But be aware that in some cases the pin can rotate in the piston and after time can "saw" off the clip tag if it is touching it at all which is why the C clip is the safest.

[@johnpower8356]

@AuMechanic ok I hear ya, I personally have never seen a clip get sawed and come apart. But I do believe if the G shaped clip touches the pin it ould change the harmonics enough to cause make something bad happen. I've seen some pretty weird problems repeating themselves in engines. Larger engines use a squared groove and clip, makes me wonder if it would work better in these, the piston wristpin bore would be easy to cut cut a square groove but I'm not sure if the clips are available. Thank you for your input

[@2smokes]

interesting but old 2strokes got even 2 of these and when buying new piston for my mopeds they all had the 1 ear and it did well no problems

[@AuMechanic]

In short, they don't cause a problem until they do, and when they do its usually lotsa of damage.

[@elitistseeker1258]

I try to avoid wire clips like that. I usually swap it out for the appropriate size C clip

[@AuMechanic]

Most 2t pistons have a wire clip so the groove as a round profile. If you fit a C clip that has a square profile that could be risky as it does seat on the rounded groove. And using any clip that has ears is problematic as the video covers.

[@arturalmeida9677]

I'm looking for piston diameter 47,5mm with 12 or 13mm pin for Fantic motorcycle engine, please

[@GasMasterBenzoTechChannel]

Bite off your ear with wire cutters and forget. Time is more precious! Откуси ухо кусачками и забудь. Время дороже!

[@2strokeguru]

The pin pushes 360 degrees how is the empty hole going to push on the clip

[@AuMechanic]

The pin has a wall thickness and it is enough to push on the root or base of the ear on the clip. Where a clip with no ear tag assures the OD of the pin always pushes against the part of the clip seated in the groove keeping it there.

[@ΜιχάληςΜιχαήλ-σ8ν]

I have damaged my engine once from this exactly reason. Very informative video

[@AuMechanic]

Thank you for the comment.

[@fernandocastillo8026]

@@AuMechanic so I’m a bit confused I’m building my first engine so the G clips with the ear are normal but you don’t want to bend the ear inwards? So towards the piston and if it’s facing us outwards is that fine or no it’s gonna be straight

[@richardmiddleton7770]

I understand what you mean but the sideways sliding forces of the gudgeon pin should be next to nothing! In fact the gudgeon pin is usually quite a tight fit in the piston so it shouldn't be moving at all. It's the conrod bearing that rotates not the gudgeon pin! I've also heard that it's the weight of the 'ear' on the clip that can cause the clip to flex at high rpm and possibly jump out of it's groove, I'm skeptical about this aswell! I think the majority of failures will be down to people reusing old clips and clips that they have bent out of shape getting them out and back in again!

[@AuMechanic]

While it is true the bearing takes up the rotational forces, the pin also floats side to side (if that was not the case there would be no need for a clip) and it does rotate enough to saw off the ears too which I did not cover in the video and should have. I have a images of clips showing the ears nearly sawn off that where removed from chainsaws in the courser of servicing pistons and if you read the comments here you will see others have experienced this also. And I do agree that reusing old clips is a bad idea for the reasons you mention. As for the clips jumping out due to reciprocating forces I also have my doubts about that. The bottom line is that using clips without ears will ensure none of the above occurs in all cases and is a small measure to prevent a catastrophic failure.

[@joescissorhands141]

Thanks, had read this concern in Glenn Blair's book recently and just looked at my pile of circlips thinking "Ok they're all either 1-or-2 'curled end' circlips, gonna need to do a careful lil grinding session" and simply remove them from the equation...seeing your "just have the proud side sticking outwards" approach makes me 2nd guess even bothering with removing them, what do you think is it worth removing them if you are setup to do so the right way? Great vid as always, have never seen one that I didn't learn from (despite my niche being chainsaws, wherein there is no expansion chamber *at all* and a good muffler design is simply about "no restriction on flow" and "some circulation so you don't dump too-much good charge" rofl) Random question I didn't see addressed by Blair(or Jennings) is "distance of piston-ring-ends from ports", I'm doing a particularly difficult build insofar as my upper transfer's edge, and intake port edge, will eat-up a ring's end if I go any further (but want/need to enlarge ports still) so am curious "just how far" you can push things safely, I know: 50thou+ overlap minimum, 2mm+ ideal for skirts against port-edges, it seems anywhere from 4-8mm of bottom-of-skirt overlap at exhaust port floor when at TDC is good...and I know 65%, even up to 70%+ of bore, widths can be achieved w/o killing a ring *if* chamfered/edged correctly....but I cannot find any "rule of thumb" for how close I can bring a port's edge to the line drawn by the piston-locator-pin(s)! Thanks for any insight!!

[@ct1762]

what about circlips that have 2 ears? surely those 2 ears are meant to be pinched (gently of course) with needle nose pliers correct?

[@AuMechanic]

That just doubles your chances of a clip coming out or loosing one ear off the clip. It might not happen to you but the only way to guarantee it will never happen is to use clips with any ears on them.

[@CZ350tuner]

I always used E clips as those G clips are risky. Jawa & CZ piston kits always come with E clips. I even replaced the OEM G clips on my Suzuki GT550 with Jawa CZ E clips. 30 years later and still fine.

[@AuMechanic]

In most cases clip wont come out, but if it does .... you might be wishing you had plain clips with no ears on them after you look at the damage done.

[@CZ350tuner]

@@AuMechanic Never had any issues with E clips in 40 years on dozens of 2 stroke top end rebuilds. Only disaster was a G clip coming out and welding itself into the side wall of a piston (the cylinder liner was steel so OK), back in 1988, which is why I now throw the things away went I find them in piston kits. E clips tension all around and the clip needs to be inserted with the ears facing either to the front or rear of the piston. Oddly enough I was teaching my "understudy" about the horrors of G clips whilst installing a 307cc big bore kit to a 1978 CZ 250 twin last Tuesday. (He's a millennial who's been bitten by the classic 2 stroke bug and wants to learn how to restore & fix them himself, including all the black arts such as setting up TLS brake drums, etc.).

[@AuMechanic]

@@CZ350tuner As a MC mechanic rebuilding engines daily it was rare, but enough to know that the ears on clips are a hazard and the purpose of the ears is ease of fitting which is not worth the risk of one coming out and as you see by the comments here it happens and possibly more often then I knew of. The ears on the clips do nothing for the operation of the engine and are only a liability and perhaps that's why most 2 strokes OEM clops have no ears on them.

[@briang4470]

I personally believe that 99% of wrist pin clip issues are caused by damaged or not fully installed clips. I personally have installed many clips that were loose after from over bending them. That's why once the clips are installed I always take a pick tool and make sure the clips are fully seated and don't spin in the groove. It's extremely easy to accidentally bend or distort the clip to the point where it won't stay tight in the groove. I don't agree with your thoughts on the G type clips, I think they are perfectly fine and I have personally seen many FACTORY assembled small engines that use the G type clips with zero issues. I believe most issues are that people don't double check their work once the clips are installed and I usually always order an extra set of clips whenever swapping pistons simply because if the clips don't seem right, I will change them for another set until all seems good.

[@AuMechanic]

I will reiterate 2 points made in the video. 1 this only applies to 2 strokes simply because 4 strokes don't have ports and a loss of a clip wont end in catastrophic failure as it can in a 2 stroke. 2 most people will never experience this fault in their lifetime, some will as you can clearly see from the comments section but in my case as a professional mechanic rebuilding many engines a day I have seen it a few times as have other experienced bike mechanics and we are in no doubt as to the cause of it. But we don't take preventative measures building engines based on good luck or based on the absence of a failures occurring on an engine we have ever seen. If a mechanic is aware that a failure "may" occur just once, then they should take measures to prevent it ever occurring if they are a true professional mechanic. And fitting clips without ears will ensure that. There is a good reason that most 2 stroke engines come with pistons that have no ears on the piston clips and instead provide a groove to remove them and this videos covers the reason why. Some engine makers do not fit earless clips and all I can say to that is that they are relying on luck only and not good sense as it would be of little to no cost to provide clips without ears on them which would never suffer this issue that ends in catastrophic engine destroying failure.

[@briang4470]

@@AuMechanic in my personal opinion I believe assembler error is the root of all the issues. I have never in my life personally seen a piston clip fail or fall out on a FACTORY installed/assembled engine. I have only ever seen/heard of clip failure/issues on engines that have been previously rebuilt or had some sort of internal work done involving disturbing/reinstalling new or used clips. Which leads me to personally believe it's due to assembly error. We can agree to disagree and that's ok. Engine building is one of the most controversial things in the world you can ask 8 different builders their opinion and you WILL get 8 different answers.

[@AuMechanic]

@@briang4470 Given enough dismantling of engines of engines that were all factory made you will eventually encounter engines not yet rebuilt with piston clip failures. The fact you have not seen something does not equate to its lack of existence And the mode of failure I covered in this videos is just one. The other mode of failure is the pin rotating that results in it sawing off the ear that then falls into the port and ends in similar damage to that of a clip failing out. You can believe that it does not occur all you like and you may never change your mind on that but that day a piston clip fails by way of the second mode of failure just described you will them discover the limits of your "belief"

[@frankcrawford416]

Dang, I just did my top end with that kind of clip and did not know about orientating it. I hope Yamaha clips have no bias. The cast oem piston for my model did not also have a slot into the pin hole for installation.

[@AuMechanic]

Well if you are concerned about it maybe you want to slip the barrel up enough to expose the clips and check them out. If they are ok then good but if they are not there is a risk of damage if one pops out or looses and ear, its not a sure thing but if it does occur it is a costly repair..

[@frankcrawford416]

@@AuMechanic Yah true that. I might put the ole beast up for awhile til I find time to check the clips, and at the same time I will put a thicker base gasket on. It is nice to bundle projects together. Thank you.

[@peraz968]

Thats true! I know, because I had a Suzuku solifer and it did that thing meny meny times.. Wery often it was broken only because of this reason. It is abaut 20 years ago, so I did'nt know it then. But now I know! And I agree with you absolutely!

[@Lecornalien]

tanks, really.

[@robertdouglas3456]

Thank you for a great video!.. Merry Christmas to you & your family!

[@AuMechanic]

You have a good Christmas too and thank you for the comment.

[@outboardfixer]

How much does that wrist pin turn during operation or is it stationary and the connecting rod moves on the wrist pin?

[@AuMechanic]

The pin does rotate in the piston even though it has a needle roller bearing. This action can saw off the clip ears

[@bf4breakingnewsray342]

When it's off i take off the sparkplug and gently pull the starter to see if i hear the bell noise thru the sparkplug hole i do hear the bell sound what can it be

[@sanderverhage5148]

It took 30 years to find out what happened to my Yamaha DT50 engine. Someone said that I probably dropped something in the carter. But I was sure this was not the case. What I didn't install correctly were the piston clips. A big mess was the result.

[@AuMechanic]

Yes such a small part leaves a big mess if it fails.

[@nickywalsh8492]

Hello again..with this type of circlip I realise I've been doing it the easy way and worse I've forgotten to use the eye in piston which I did back when I worked on my rd engines.. when I've noticed a byest on the ear I've pryed it inti line not realizing I could have just turned the bugger...it's chainsaw engines I play with now...and take dead saws back to life...and end up with something has a value.I'm sorry ur struggling with channel..but at least ur fighting back...👍I've some nice content if you have time pls look

[@AuMechanic]

Back in 80's a worked at a Stihl dealer for short time tuning and repairing chainsaws. Didn't mind working on them but had me sharpening chains too so I lost interest in that job fairly soon.

[@nickywalsh8492]

@@AuMechanic haha... I'd sharpen chains gladly before turning a screw on a stihl..it's a weird thing I just have no ambition too...husqvarna/jonsered👍...I'm waiting on parts to finish a 94cc bugger ..stock set up...it's far to easy to change the ports for the worst..Now I've a question mahle oem piston 56mm bore ..New kit coming reusing cylinder ...your thoughts on piston/bore clearance...mine are 0.06~0.10 am I way out...not that I could much about it...

[@AuMechanic]

Re piston clearance, not much you can do if it's got plated bore other than get another cylinder it it's worn. No cheap ones on Ebay ?

[@Fridgemusa]

@@AuMechanic I hear you on the chain sharpening, been there, done that, got over it real fast :(

[@AuMechanic]

The down side of working at a small dealer, they didn't do enough chain saw mechanical repairs to fill the day so made the time up doing chains.

[@bf4breakingnewsray342]

Question my brother if you have 1/5 scale turned on and you hear a bell noise thru the sparkplug area what can it be it's not the clutch I'm100% the only thing i can think of is the piston

[@willberg8599]

Dose sum thic boi rings! My cr500rs’ are like half the size

[@jackmills5071]

Hi, I've made a pipe following your videos, and on the pipe I've got a dirt bike style straight through silencer with proper insulation material. Despite this it is still very loud, and I was curious how i could go about making a more restrictive silencer and adjust the stinger diameter accordingly. I've downloaded a copy of Blair's book so if you have a page reference that would also be great. Thanks for the great videos.

[@AuMechanic]

Gordon Jennings used a method that i also used which was to insert the outlet pipe back into the diffuser cone past the mean reflection point which would reduce the sharp crackle of the sound with no power loss. You can find info on that in his book "Two-Stroke Tuners Handbook" page 69 Blair has an expansive chapter on mufflers in his 1996 book (Chapter 8 page 541) and provides some equations to go and I was going to do a video on that at some stage.

[@jackmills5071]

@@AuMechanic thank you for the help it is much appreciated

[@bryanbisimotopinas345]

@@AuMechanic 69 nice.

[@briansurbersurber5330]

@@AuMechanic what if there is no slot in the piston?

[@AuMechanic]

@@briansurbersurber5330 File one, or, if you are going to use a clip with ears be careful as per instructions in the video on fitting one.

[@eddiegilson5201]

Problem is, with most European performance cylinder kits, there is no indentation on the piston. Please advise

[@AuMechanic]

If it is an OEM kit then Id probably just go with the clips they provide with it (even if they have ears), just not using the ear to install it with needle nose pliers, but levering it in as I do in the vid so as not to risk bending the ear inwards. OTH if its aftermarket Id probably slot the ends of the pin hole with a small dremel burr tip to allow removal of a non ear type clips.

[@emmababe5334]

thank

[@vespasandengines]

So why do you see the G clip with some 2 stroke engines?

[@AuMechanic]

Poor design and most often found in cheap engines / piston kits.

[@Blacksican9]

So my piston does have that grove to put in the clip. What do u suggest?

[@AuMechanic]

Either way, use a clip that does not have the "ears" on it. The slot just makes it easier to get the clip out.

[@andresvignolo9135]

Hay alguna posibilidad de que se coloque la opción de subtítulo en español? Cómo los.videos de cálculo de escape que también están igual! Son muy instructivos pero muy difícil entender

[@AuMechanic]

You will need to use Auto translate. I put CC on all videos for this purpose.

[@blainemacdonald6929]

Hey Dave I was wondering if you could help me with 2 stroke ignition timing. I would love to hear your approach

[@AuMechanic]

Yeah sure, what did you want to know ? See channel :"about" page has my email if you prefer to send there.

[@blainemacdonald6929]

@@AuMechanic I couldn't find an email just twitter and instagram and I don't do either of those.. but here is what I have done. I have built a cr500 for ice racing and I have installed fuel injection so I don't have to worry about carb icing and changing jets at -40 with that I have programmable ignition. I was thrown of because I expected a curve similar to a 4 stroke but when I read Gordons book it seems it's completely different... Happy new year

[@AuMechanic]

@@blainemacdonald6929 The amount of timing you need loosely dependent on the density of the mixture. Or to put it another way, the lower the density is the longer the burn time and therefor the earlier you need to have the spark BTDC. So as mixture density rises in the 2 stroke with RPM as it rises to the power band, the burn time reduces needing less advance, that tends to offset the fact the engine is going faster that would require more advance as in a 4 stroke.. To the degree that in my 350 Yam road racing for example I had no curve at all. But that will depend on the specific engine.

[@fastidiouspa]

If when installing the pin you scratch the piston at that point is the piston no good? I’m changing the piston and ring on my sons KTM 65 and I wish I would’ve seen this video before I did. When installing it I scratched piston. Thank you.

[@AuMechanic]

If its only a fairly small scratch you could use a sharp tool to "carefully" scrape off any obvious high spot along the scratch and then give it a rub just over the scratch with some very fine grade sand paper to clean it up. 1200 wet and dry will do.

[@willbigv8]

Thanks for that. Very informative. My questions to you can you grind the ear off the clip and if your piston doesn’t have access slot can I grind one in?

[@AuMechanic]

You can file a very small slot in it enough to get a scribe in to flip the pin out next time around. (Keep in mind this is only for 2 strokes)

[@ajadsudrajad2810]

urang hnteu paham,😁😁👍

[@WillyD1]

What about the ez clips with two ears slavens has them I’m not sure if I should use them or not?

[@AuMechanic]

You can use them but just be aware of which way you fit them as described in the video and check them for any bias as described in the video.

[@thayoutubebigwig1109]

wad dat iz? i got to bore a dt100 ebduro man,,..like

[@KILLERPANTHERDUDE66]

With the thickness of thos rings im sure it would chew it up and spit it out tge exhaust

[@AuMechanic]

Yeah it chews it up alright. But unfortunately the clip is steel and the piston is ali and steel wins. The other issue is the clip is perpendicular to the ex port in the piston pin hole and more in line with transfers so to make it out of the exhaust it would first have to go down the transfer port without the piston chopping it, and then pop back out the transfer port once the piston is at BDC and then go out the exhaust and that's pretty long odds.

[@experimentchannel1776]

Man Thank you so much I’ve had 2 engines destroyed with the dam g clip ears braking off and now I see why, can u just remove the ear? And file a notch for seating the clip as my piston has none. Wee Story- ones I was 20 kilometres from home engine started making odd noise clutched in immediately had tool kit with me so open up engine seen clip eir broke off which broke a ring and made like 3 Grooves in the piston and cylinder at least 1mm deep this was at the bottom and few lighter ones up the top end so I started sanding away trying to clean it up changed the broken piston ring and cleaned out the crank best I could put it all back together and luckily it started up and got me home, changed out the engine after that haha...

[@AuMechanic]

Yeah makes a mess when it comes out. Yes you can grind off the ear if you cant get a clip without one. If you snip it off just make sure there is no burr left so it seats in the groove fully. And yes you can file a small notch the allow it to be removed, just do it to the side of the hole like the piston in the video and not the top or bottom side.

[@experimentchannel1776]

AuMechanic alright cheers for that.

[@ebike5548]

Hi there this video is gold thought me a lot I don’t know but my circlip slot wore out allowing the clip to come out and I’m wondering should the circlip be a real tight fit or free to turn around in there? I uploaded a video of it and was looking for similar videos on my problem and can’t find any I must be doing something wrong can anyone here give me advice thanks.

[@AuMechanic]

It should be a tight fit. Also don't re-use old clips and be careful when refitting the clip repeatedly that might damage the slot. With the Chinesium engines be sure the clip used fits snuggly in to the slot and there is no sideways movement or the slip will wear the slot away in time. For example if the wire diameter of the slip is a little smaller then the radius of the slot. When removing the ears of the clip be sure to finish if the ends too so there is no but that might cause the slip to not seat properly.

[@ebike5548]

@@AuMechanic Thanks for the reply, I ordered a few cir-clips I’ll make sure they fit snugly each way cheers I really appreciate that.

[@stevo450ify]

Wait... You're not Dave from two stroke performance??

[@AuMechanic]

No.

[@stevo450ify]

@@AuMechanic haha just checking, he's also Dave and another two stroke genius! Thanks for the amazing material it's very interesting and educational!!

[@shoominati23]

You thought business was tight back then champ? ha ha ha ha

[@t_4178]

chainsaw builders cut off the tail, as these engines can rev to 4-5k and that extra weight and wiggle it out

[@burtsimmons9691]

So do you use a sir clip with or without a ear

[@AuMechanic]

Without an ear for 2 strokes

[@burtsimmons9691]

AuMechanic thank you

[@kraftzion]

Great channel, I watched hours and hours of videos before i got this channel as a recommendation. I guess I had to watch enough to learn what questions to ask to get here. So if the choice is between grinding a slot or using the tabbed retainers I should grind a slot? Edit: found the answer in the comments!

[@rjuarez4913]

Thank you sooooo much.

[@AuMechanic]

You're welcome.

[@danajett]

My piston clip came out and went inside the engine. I haven't even finish breaking it in in ĵust 2weeks it's over lost compression smdh

[@AuMechanic]

Damn, sorry to hear it. What sort of clip was it ?

[@danajett]

The same clip as in this video but the engine still runs now​@AuMechanic

[@christianscottsuzuki]

What if you use internal retaining circlips. The same type that have the two hole at the end. I hear disels use them

[@AuMechanic]

Don't use them, the cross section of those "snap rings" are square shaped and the cross section of the slots in the pistons are a round shape so the square section snap rings will not seat properly and can come out even more easily destroying the piston and cylinder.

[@christianscottsuzuki]

Those are internal retaining circlips. I think you got the wrong idea

[@AuMechanic]

@@christianscottsuzuki No not in 2 stroke pistons, but if you want to use a square cross section snap ring then go right ahead, best of luck.

[@christianscottsuzuki]

@@AuMechanic there is no square cross section though??????????????? Ru talking about where the pliers grab?

[@christianscottsuzuki]

Ehat about the peope who already have been running them and the diesle engines

[@richardworden9747]

Is it the same on a 4T engine ?

[@AuMechanic]

No because 4T has no cylinder ports.

[@Gazgit555]

top tip!

[@AuMechanic]

Glad you find it useful

[@edwardjames6070]

wrist pin clip. always use a new one. that bitch has happened to me more than once. they get worn out and don't have the temper (strength) to hold it in place any more. I'm as cheap as the next guy and this is one time NOT to be cheap and reuse.

[@AuMechanic]

Agree, new one each time if you can.

[@mmypainting]

Just rebuilt my chainsaw, excellent.

[@AuMechanic]

Need to do a rebuild on my 372XP that the piston cooked in a few weeks back

[@microfarmers]

I use circlips

[@AuMechanic]

Well...... that's a good start.

[@thayoutubebigwig1109]

I usuall just pop da stuff in

[@dmitriy6275]

What about 4 strokes?

[@AuMechanic]

Not a problem because 4 strokes don't have ports in the cylinder for the clip to get "guillotined" by the piston as it can in 2 strokes.

[@dmitriy6275]

@@AuMechanic oh, ok, thank you so much, because I'm doing a top end rebuild

[@tomisuikkari992]

sorry man... we tried this one out and we bent the clip and assembled the engine and all that happend was a little grind on cylinder wall

[@AuMechanic]

Luck was on your side it didn't hang out in the transfer port.

[@fuzzy1dk]

had that happen on moped many years ago, never found the clip and the cylinder was scrap with a 2mm deep piston pin wide groove in the side

[@tomisuikkari992]

@@fuzzy1dk I highly doubt that you didn't just have your c-clip seated correctly....

[@AuMechanic]

@Lasse It sure makes a mess if the transfer chops the clip.

[@fuzzy1dk]

@tomi you are right, it might never have been installed, the damage was from the pin rubbing on the cylinder

[@bryanbisimotopinas345]

hot dam. i'm gun watch more

[@AuMechanic]

Enjoy

[@BattShytKuhraezy]

Hopefully ,U r well. Newer content appreciated!!