Replacing the Top End

[@PMWgoped]

@narinderman the star shaped in the screw makes what is called a Torx screw so a Torx bit is needed. Just about any hardware store will have a proper "Torx" set that will do the job. I forget exactly but think the one needed is the "T15" torx bit.

[@PMWgoped]

Ryan, also make sure you have the celebrator manifold connected properly. The engine can behave that way if the manifold is upside down or has the vacuum pulse port that pass through the manifold blocked in anyway.

[@PMWgoped]

@ryan probert check that the piston is in the right way and make sure the carb manifold and the vacuum pulse port is correctly reinstalled.

[@PMWgoped]

Maybe but make sure the carb, manifold, and gaskets are installed correctly, it's possible to install them in a way that blocks the vacuum port (small hole next to the intake port on the cylinder) from reaching the carb that is needed for the internal fuel pump. It can be very hard to start if the piston is installed backwards or if you have a damaged gasket so those items should also be checked. when trying to start make sure your not flooding the engine with to much fuel.

[@PMWgoped]

The piston ring rubs the cylinder do to the tight tolerances. Without any lubrication in the engine the rubbing feel and sound will be aggravated. A couple of important things to be mindful of when rebuilding a top end are: Piston installed correctly, if can be put on backwards by mistake. and Do not forget the piston pin retainer clips. Without the clips its a matter of time before the piston works its way out and catches on a transfer port. Either of these will also make a strange noise.

[@PMWgoped]

There is typical a engine make and model tag/sticker found on the engine case. If you can take it to a GoPed dealer or even a small engine repair shop then they may be able to know by looking at it.

[@PMWgoped]

Typically the exhaust side. Check the piston as there should be an arrow casted or stamped on the top of the piston that should point to the exhaust port when assembled correctly.

[@PMWgoped]

The flywheel is held on with a nut and the taper of the crankshaft like the drive spindle (see my removing drive spindle video). Remove the flywheel nut and find a threaded hole in the flywheel. Now use a long bolt that you can thread into that hole until it bottoms out against the crankcase then with a few more rotations of the bolt, the bolt will pop off the flywheel for you. remove the old flywheel key, replace with your rocket key and reinstall the flywheel to be done.

[@PMWgoped]

@Tvmonster666 That would be my guess. But if the ring broke in the engine when it was running then it may have damaged the cylinder and piston so you will need to also inspect those parts for damage.

[@PMWgoped]

@littlede1996 make sure the crank spins freely, you can soak it some anti-rust formula to remove as much rust as you can, and run it.

[@PMWgoped]

@narinderman The hardware or auto parts store should have a screw driver with replaceable screwdriver tips. Many of those types of screw drivers come with Torx bits but if not the store should have the tips you need too. Ask for assitance and if they dont have it then they can tell you where to get one.

[@IHAVE99NOSES]

Shouldn't you hone the cylinder walls for a proper piston ring seat? I have a g23lh that I am rebuilding with a brand-new cylinder and piston+rings. I don't even know if anybody makes cylinder honers small enough for these engines...

[@PMWgoped]

Make sure the gasket lines up with all the holes to whatever it is fitting with.

[@chadman2275]

Goped was the og fun times no e bullshit nonsense just wide open 2 stroke all the time 🤗 miss my ped.

[@PMWgoped]

@littlede1996 Give me some time and I will see what I can do. I should be replacing the seals and bearings on one of my Go-Peds befor spring. If I get a bottom end job befor then, then i will have a video for you even sooner.

[@PMWgoped]

Well, that's an aftermarket part and I am trying to stick with just stock. There are simply way to many variations and combinations available with aftermarket parts. What you will need to do is to remove the flywheel. there is a trick to getting the flywheel off and I will post that trick below since I am limited to only a 500 character count.

[@aadams4328]

I want to remove the front brake on a Know-ped and add a rear brake (either V or disc). Was thinking I could use GSR sport brakes since the wheels look about the same. Any video's for that kind of thing? Thanks!

[@abel081]

You should make a video demonstrating how to break in a goped after upgrading your stock head kit with a big bore head kit cause some of US like to do it ourselves cause ppl charge a arm to do for you cause takes time and 5 gas tank tops so I been told . Please make one

[@PMWgoped]

Abel, When breaking in the engine you just want to avoid holding high RPMs for a long period of time. Keep it to under 30 seconds at a time to be on the safe side. Now with that understood you will do that until you have allowed the engine to go through several heat cycles (ie: start it let the engine get hot and after 10 minutes of run time, shut it down and let it cool for at least a few hours and repeat. 4 or 5 times of this and you are through the bulk of the break-in period and you can start using it harder and running it longer at full RPM. After your though 3 tanks of gas, you could fell confident the break-in period is done.

[@braddayberry2233]

Are there any torque requirements for the head or did you just make her nice and tight.

[@axiomloves21]

Must be a cheap carb with no settings.

[@PMWgoped]

@lifeisshort21 Your welcome and thank you.

[@PMWgoped]

That's not a a fuel line, but is a vacuum pulse port line for the internal fuel pump in the carburetor. That's just how they do it on that engine model. Other engine models have the vacuum pulse go through the manifold that lines up with the vacuum pulse port on the carburetor so you don't have an external vacuum line like this engine. (matters not)

[@tylerclark6990]

I have a gsr cruiser and it been sitting for almost a year because my friend put stright gas in (its basically brand new)..I just got it back yeasterday and I cleaned the carburetor and new gas took off the head but the piston looked ok...I got it running it was fine all day 1 pull cold start would fire right up.. but the I was riding it and it slowly stalled on me, now it wont start. Can you please help

[@PMWgoped]

Yes the G43L-D engine on the GSR40 will not be much different once you get the covers off.

[@PMWgoped]

@littlede1996 If the engine still runs, it would be my guess telling you how much life you still have in that cylinder. It would not hurt having a spare handy.

[@liama32]

gret vid just wondering why is the fuel line going from the carb to the manifold ?

[@FrenchValleyAirport]

does the piston ring(s) have to go on/face a certain direction?

[@offroadhooligans8701]

Normally the cutout on the pistont ring has to be were the lil nub is on the piston

[@meanoldrunk]

i just bought a used goped for my kids. it wont start has spark but wont start. thinking about rebuilding it or maybe just buying a new one and rebuild later... how do i figure what motor i have. thanks for reading

[@littlede1996]

My bore the silver coating is wearing away most of it is gone should I replace the bore

[@3258462]

i am trying to remove the head from my gsr 40st to clean out the head and piston is it basicly simalar to this ?

[@jesuscamacho6173]

Can you make a video on how to remove a seized top end?

[@pikeybear]

do you just push out the piston pin thing

[@jakejarmolinski9603]

What kind of lube did you use when putting the piston in to the head?

[@PMWgoped]

Yeah, but you need to remove the little wire clip that hold the piston pin in place first. Be careful not to bend the connecting rod when trying to push/press the pin out.

[@Drumming_is_like_a_heart_beat]

How do you know if the gaskets are backwards?

[@littlede1996]

Pmw should make a vid on how to change crank seals and bearings

[@dudeeric12]

i think your right im using a ufo air filter with a stock carburetor and i dont think i can tune it

[@Branhawk]

do the gaps in the piston ring need to be on the intake side?

[@PMWgoped]

Sounds like a good plan to me.

[@ryanharris6102]

Hey I have a g23lh and I just put a cy 29 cc big bore kit with a 2mm crank and a wt-18 carb and now it wont start its getting fuel and it has spark could it be the fuel. My brother put my gas can out side in the sun

[@romulobello8994]

what tools did you use? are these compatible with the gsr40

[@littlede1996]

There is rust on the crank but the engine is not seized what should I do

[@PMWgoped]

Not really, because typically you change a top end when the rings and cylinder have worn past there useable life or have become damaged and need to be replaced not because there is carbon on the piston. Carbon build up on the cylinder typically does not hurt anything.

[@ryanharris6102]

It also sound like the piston ring is rubbing on the cylinder and it has never been started

[@pikeybear]

do you think you could do a vid fitting a rocket key ps great video your vids allways help me

[@dudeeric12]

i got a goped sport and when i go up to top speed it starts making a weird sound and starts to slow down a little if any one can help me that would be great

[@PMWgoped]

@adamkeffer unfortunately I can't help you in just 500 characters that KZbin allows in comments, but I did send you a reply to your message. Thanks for sending that to me.

[@ViralWatchMedia]

how come that motor has just one ring and mine has two??

[@Tvmonster666]

i have 2 rings on mine 1 broke and doesnt run is that the problem

[@PMWgoped]

This sounds like the carburetor is not tuned correctly. I would love to help but I am going to need a lot more information then that.

[@PMWgoped]

get just the bits for a changeable bit screw drive

[@nextstepautodetailingllc969]

i changed the piston in my goped and now engine dies when i give it gas but works good on idle what should i do??

[@joejohns4184]

ryan probert adjust your carb it sound like not enough petrol is getting through

[@FLBOARD]

hey !!! i have a goped sport with a g23lh motor and it runs starts drives but it makes this weird sound.. it sounds like a high pitch scream and i dont know what it is. i think its my piston rings but im not sure !!! please help

[@PMWgoped]

Piston rings normally do not make much of a noise unless they are broken but the noise is then a more of a crunching sound just before the engine seizes. I would suspect the main engine bearings to be the source of the high pitched scream or possibly the engine cover is damaged and rubbing on something. Without seeing and hearing the noise this is just guessing though.

[@AlexMaciel241]

Its probably your flywheel

[@Branhawk]

Thanks

[@tdh0084]

ok this is a good video, BUT, I REALLY FUCKING WISH SOMEONE WAS EXPLAINING EACH STEP!!!!!!! i feel confident in my abilities but the only question i have is what did he do to take the piston pin out? do you not have to remove the cir clips? it looks like he just pushed it out but i thought that it was held in by 2 cir clips. Then it showed him putting the cir clips in AND THEN sliding the piston pin in... im just confused. i thought that you had to take the clips out in order to remove the piston pin or did this video just skip over a step or two? PLEASE SOMEONE EXPLAIN IT TO ME. i have a brand new top-end kit for my GP460 and i DO NOT want to call a friend to help me. i feel like 85% confident in my ability to change the top end and the only reason im doubting myself is because i didnt see the guy in this video hardly do anything with the cir clips. i really hope im missing something and that im just a dumbass (which i probably am) but id really like to know if im right or wrong. someone please email me. please. [e-mail] in the subject like just put something like "KZbin GSR46 TOP END COMMENT" and please use ALL CAPS so i have a better chance of seeing it. to anyone who reads this all i have to say is thank you. seriously thank you. i know that changing a top end is pretty fucking simple but i want to make sure that i get EVERYTHING right. i just want to cover all the bases. Thank you for reading this comment. Please hit me up. Have a good one!!!!!!!

[@pikeybear]

oh right as i am goin to big bore my lh so i thought il do my rocket key while its neally all apart lol

[@PMWgoped]

@mastax1234 Easy, diffrent engine model.

[@longboardcopper367]

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