Ignition Timing Explained & Tested : How-To Advance & Retard Timing With The MVT Digital Direct

[@TheDefiantInfidel]

My career modifying two and four stroke engines has now spanned 51 years. I have modified everything from Formula One outboard tunnel boats to trials bike engines, drag racing, road racing, hill climbers, flat track, sleds, airplanes and ultra lights. I teach an internal combustion engine class on a volunteer basis once per week at a local Christian school for grades 7 through 12. I watch TONS of videos looking for those very few exceptional creations that I can recommend to my students, knowing that their information is accurate and useful for their “home work” and further study beyond what my time in the classroom with them can provide. I find nothing inaccurate or worthy of criticism in your EXCELLENT explanations! I am truly impressed with your precise, articulate and well conveyed materials. You are a RARE and very well versed gentleman, Sir! No arrogance, condescension or smart ass attitudes whatsoever. Just concise and real information. In my humble opinion, you are a learned GIFT to the industry and I sincerely salute you. Very well done! 19:51 Many deserved thanks!

[@49ccscoot]

Thanks very much for the kind words!

[@TheDefiantInfidel]

@@49ccscoot No, thanks required, Sir. You earned every syllable. Very best to you.

[@taz9609]

to explain something so complex so well so that it is easy to understand takes a genius. thank you

[@aliciaantoniadis9100]

I agree 100% with T A Z. He just beat me to it this time. Awesome video as always and I thank you so much! Sincerely, Alicia

[@Truther00]

This guy knows more than he thinks he does 👍🏼

[@iKenFlyPPG]

4-stroke engine calibrator here, I have limited 2-stroke calibration optimization experience beyond the basics. Nice job researching and explaining the theories. I've been spoiled testing $150k prototype engines in $10m test facilities with all the dynamometer toys. I lust after cylinder pressure measurement setup, this is the future of home diy tuning, when OEMs start using cylinder pressure sensors on production cars, not sure when that will it's very costly to get accuracy and resolution today. On the bright side, you don't really need all that to maximize your fun, because we got folks like 49ccScoot to help us through.

[@m5300a]

Educational as allways! Here in Serbia (Europe), we have scooter forum since 2007 or 6... Our God is also Mr. A.G. Bell :)

[@MetaloMan007]

I have watched tons of videos explaining ignition timing, but they caused more confusion.... With your explanation I could realize everything so clearly, each step was animated in my mind...thank you soo much

[@dylanjones678]

I was wishing there was a calculator like this about a month ago, glad I found this video! Thank you sir.

[@undefeatedloser5221]

This guy answered all my problems in mind, thank you sir..please share more of your ideas

[@muhdizham1028]

Tqvm bro for the knowledge, I'm now more understand about ignition timing.. because I've made a up stroke to my motorcycle then I've a knocking problem..now i know what to adjust to my ignition timing..keep it up bro

[@pl3a5enophotoz]

5/5 stars mate now I know my timing too advanced! Can’t thank you enough!

[@julioraizer2682]

Awesome video, I used to think we needed more advance to make a 2 stroke rev higher. I'm modifying a motorcycle engine for a go kart and gave up advancing it for now.

[@shamzrockkapak]

Tq sir for the knowledge..easy to understand..😊im your supporter sir..from malaysia🇲🇾🇲🇾🇲🇾✌🏻✌🏻✌🏻👍🏻👍🏻👍🏻

[@Wonderfulworld-l9s]

You're a genius.

[@patrickfargie1146]

You need to make a master class with your knowledge.

[@racehappy]

there's a lot of self centered f^#K's that can't give a thumbs up or leave a comment that is very sad when seeing how many views you've gotten. Thank you for taking the time to make this video shared it with my son so he understands how to fix his racebikes.

[@49ccscoot]

Thank you!

[@mehriran1020]

Awesome. Completely useful & helpful. Sincerely yours.

[@nealmohowitsch1593]

A great job of explaining & the how & why to you moves 👍😊

[@LukeSchiralli]

Best explanation I’ve seen! Thanks

[@dpiper2580]

Fantastic explanation and side notes

[@austinrice2686]

Thanks for your video, I found it very helpful.

[@derrenlambert2279]

On lambretta we use a buzzwangle mercury switch attached to the flywheel, the digital read gives you degrees on the flywheel.

[@49ccscoot]

Hehe. You said buzzwangle.

[@derrenlambert2279]

@@49ccscoot kzbin.info/www/bejne/sHXGd5ebbteViNE

[@corailsigan1131]

Très bonne idée ce test!! Merci super video! 👍

[@handendaer]

Great as usual. Keep it up my friend

[@robertpierce1981]

The formulas section of this video remind me of the video on finding your actual compression ratio. If you get into the timing in the future- make a piece on the mini lathe so you can adjust the timing via an Allen screw set at a right angle to the crank shaft. If you put a lock nut on the Allen screw and chart the degrees per turn of the screw you may be able to make very delicate but accurate adjustments of the timing advance.

[@bufunga]

i have put on a 100cc kit and since can get it to run right. seems it wants to run leaner than before . even the stock pilot jet(28) seems too much to idle. thanks for all the vids if it werent for you id be lost.

[@49ccscoot]

Sometimes they do work better with a smaller jet. The larger bore may be able to draw in more fuel with the same size jets. If it's a drastic change, look for issues with the new cylinder kit.

[@bufunga]

@@49ccscoot you are freakin awesome. 👍

[@chiradip24]

Very very informative video... Thanks a lot.

[@alextrotman2743]

Amazing thank you that was really clear

[@sidecarbod1441]

There is plenty of BS on web with regards to 2 stroke engines, I watched your video and there is not even a faint whiff of BS, all good stuff! I even spotted that you showed the positive AND negative pressure waves in your exhaust simulation!. BTW I have read A.Bells book many, many times! I'm rebuilding an old Honda MT5 at the moment, its the trail version of what you might know as the MB5. I've had about 54MPH out of it on the flat which is not bad because when they came out in the UK they were restricted to 30MPH :-( I do have some ignition issues at the moment and was looking at the MVT system as a replacement but I need to do more investigating, for starters I need to find out whether the rotor will fit the taper on the Honda's crank, then there is the charging at lighting circuits to sort out too.

[@49ccscoot]

Thanks. I've been pretty happy with my MVT. Good performance vs the stock scooter stuff. Not an abundance of charging/lighting power, but it can get the job done well enough. Seems a bit tougher to tame (regulate) the voltage on, but I'm revving to 14,000 or a bit beyond. No idea on the fit for yours.

[@ahole5407]

And just like that.... All the kids go out and advance their timing 4deg 😂 Seriously though, good video. I really wish there were more maps available for review on the AM6. MVT makes the millennium with two keys for switching to digital which that unit has 3 curves with +/- 3deg adjustment on each with just a flip of a switch. The TPR kit has an offset key but it is not supposed to be used with the TOP red CDI. No details on the curve it provides Again, I would like to see some Dyno graphs on this 86 using different curves as to see where exactly this motor needs to be to have it singing.

[@beslimjanuzaj8350]

You have made a fantastic clarification. I need a clarification: at what level does the BTDC spark plug start firing, and when does the spark end at what level (BTDC or ATDC)?

[@49ccscoot]

The spark is a brief event that takes place totally BTDC in most cases. Combustion takes a while and should be happening both BTDC and ATDC. Any detail is going to vary from engine to engine though.

[@ArunaVidu]

Can you please do a similar video for a diesel engine

[@davidjuddnovilla3712]

Plus one subs here. Salute

[@mihustefan6662]

Many thanks for brilliant explanations!

[@OutsideJustin]

Well done

[@edboer2851]

Great vid,thanks you sir👍✌️

[@martink.9442]

Man, you need a dyno 😁😉🏁🏁

[@m5300a]

Also need EGT. Cheap China K-typ temperature sensor up to 800c with 1m wire and tiny 12v display (all for under 10usd) will do the job, just for fine tunning. Only negative is to drill header on Malossi pipe. 🛵🚀

[@denniswilder3014]

As a Dyno is great to have but a decent tuner can read the plugs to see what's going on look up plug chopping

[@kostaslazaridis9065]

Very nice job, covered almost everything. I was wondering if there is a form or a calculator which you can calculate the settings from the begining with a programmable ignition, at each rpm, just like building an engine from the beginning, without having factory's settings

[@49ccscoot]

You mean calculate the ideal settings right from the start? I'm sure some complicated stuff with CFD and that sort of thing included could get you there or close, but there's probably always going to be tuning. It would be easier for the average person to take an educated guess based on norms / other setup and then tweak it.

[@neco1562]

BRAVO MASTER

[@maheritoky7827]

Great video. can I set my ignition using just a graduated disc? thank you

[@49ccscoot]

If you know what spec you're aiming for, you could use a degree wheel. Distance BTDC is the most common way to do it though.

[@kirubakaranvijayakumar9866]

Thank you

[@jmagz2749]

hi sir! great video. just want to ask whats the best timing for my engine i have pushrod modified engine 72mm bore 56.4 stroke my mechanic told me that he retarded the timing a little bit. now i can feel the engines power when it hits 6k rpm above 5k below feels like just stock engine which is 67mm bore 56.4 stroke. dont now if it has anything to do with timing. id be very glad if you answer my question. thank you so much and keep up the good videos

[@49ccscoot]

No one can really tell you the perfect timing for your engine, without testing. That's why people pay for dyno time or tuning and spend so many hours with test lights and doing test runs. If someone knows very similar combos to yours, they can probably give you a good educated guess. I would look to others with similar engines first, or see if you can find a dyno shop if you really want to dial it in. Otherwise, you could take steps similar to what I showed in the video to test and tune your way to stronger performance. Sorry that I can't give you a timing spec.

[@johnnynewburgh9745]

Thank you for your time great video. I am having issue with a yamaha rd 350 not going past 6k rpm supposed to 2mm btdc may have been off a bit lining up rotor notch to pickup edge no key in fly wheel.thinking i may be advanced and sounds like hear rattling in cylinders

[@49ccscoot]

If you're questioning it, then to me it would be worth the time to recheck the timing spec.

[@johnnynewburgh9745]

@@49ccscoot thanks will do

[@Josemanc]

Cool info man... "Fancy valves".. hahaha

[@franciscoaranda3704]

They can keep’em

[@ratdad48]

Geesh!

[@noahthepetrolhead]

I've got a Chinese 2stroke scooter can I do a similar thing with the timing like you did with project taotao? I'm trying to do a lower rpm build for something a bit different than the usual 14k rpm builds

[@49ccscoot]

The 1E40QMB can actually be adjusted way farther than the 139QMB with a fairly simple modification to the stator plate. You really have to be careful though, because you could throw the timing way off. I've got an old vid that shows it : kzbin.info/www/bejne/aZWbonuEg85oeaM

[@noahthepetrolhead]

@@49ccscoot OK thanks 👍

[@giorgiofireblade]

Hello, I have a cbr 150 big bored 171 with pe28 carb and an ignitech, I would like to know if there is any upgrade map or how many degrees would I set as max for safety (rev limit 11800)before I blow my engine, it is for circuit use, thanks

[@49ccscoot]

I have no idea about maps for that or what it needs. It would have to be adjusted to find what works unless you can find a map for similar setups. Even then, you'd need to adjust some with dyno tuning or lap times if you want every bit out of it. If you want to stay safe, I'd slowly work up the advance and keep an eye out for knock, overheating or any signs of peppering on the spark plug.

[@LiloScooterPerformance]

we are using this ignition on a 70cc racing setup. Is ist possible and good for increasing the power, if we turn the stator a little bit more in left or right way? or it just can be measured on a dyno ?

[@49ccscoot]

You could definitely make measurable power if you get just the right ignition timing... or lose power if you get it wrong. It will not be exactly the same for every setup.

[@nickfarri]

Hello, I installed the MVT with the RJ34-6 CDI on a Honda DIo (41.5 mm stroke) at 0.35mm BTDC. I then watched your video and Pitobread video and I found out the curve you measured. I wish I watched before because 40° degrees advance till 8k rpm overheated my Cylinder and almost melted the exhaust and ruined the cylinder. I watched Pitobread suggesting to keep 28° at around 3k rpm. I was wondering what happens to the curve If I set 28° advance at 6k rpm ( Peak advance for MVT Curve) at 12/13k rpm or in general how the new curve is modified? Consdirering I drop by 14 ° the peak will the new curve be the same with 14° less at each step? I hope my question is clear. Thanks a lot in advance from Italy!

[@49ccscoot]

You can't change the curve with that CDI; only the mechanical timing setting. So yes, the entire curve advances or retards by the same amount.

[@nickfarri]

​@@49ccscoot Thank you very much. I m not too sure regarding delaying by 14° degrees will work..at 13k rpm I will have approximately a 1° advance... I guess you are not having overheating problems cause you use the engine either at idle or at full throttle... Is there a CDI that can be adjusted to custom timing? The MVT EPROM does't seem so be so adjustable, I checked the curves you posted on your website. Any help or suggestion is Welcome? Thanks, Nicola

[@49ccscoot]

@@nickfarri I'm not aware of one. I switched the whole ignition very recently because moving the curve forward and backward just doesn't solve many problems. I needed more advance with a bigger carb and then my advance at lower RPM was way high.

[@nickfarri]

​@@49ccscoot The selettra curve for my knowledge seems much better. But no lights and no plug and play for honda dio. Thanks again for your help

[@49ccscoot]

@@nickfarri The lighting is what held me back from other ignitions for a long time. Look into cordless tool batteries though. Seems like a pretty easy way to quick swap and get some good batteries in there, with the help of a step down (to 12V). May not make as much sense if you don't already have some cordless tools around with good batts.

[@joescissorhands141]

But.... If timing is based-upon the RPM level, then don't we have to "choose" which RPM we want to optimize timing for? For instance I'm building a 92cc chainsaw (2, actually, a side-by-side build of sorts), and one thing that's BLOWN my mind is how - with chainsaws, at least - the specs always list "ignition timing @X RPM", and then "ignition timing at y RPM" (usually they're Idle and Full Throttle RPM's for the two, respectively) Do you think this means the coil is "smart" and literally doing varied firing-rates based-upon RPM? If so, any keywords you could give so I can learn more? (think I *have* to learn Re magneto's/etc no matter what at this point because I'm doing a "build type" that is pure uncharted-territory) Should mention this coil is NOT one of those fancy new engine-managing coils, it's the same type found on a 1975 chainsaw/blower/weed-whip/etc, I always figured they were "single spark rate" based on their position ONLY but seeing spec pages listing different ignition-degrees based upon RPM has me so confused here!! LOVE how you mention your approach to it IE 'retard it a few deg., advance it a few, see what happens' -- believe it or not but I've NEVER heard the word 'retarded' in chainsaw-tuning, which is so weird because you'd think retarded timing would be pretty critical because it's "needed" for running high compression (a chainsaw build is just a high-compression NA build after all!) Had never played w/ it myself, either, and just received the tool & a couple flywheel-keys (how we advance timing, shaving thousandths off a 'flywheel key' on the shaft), intending to advance timing because "I'm going for power" and as mentioned it's literally the only timing-manipulation I've EVER heard of in the chainsaw world, so weird because it seems so central to all other engine-builds (IE whether timing needs retarding/advancing, and by how much) My engine's OEM spec is 13.1:1 comp ratio so will be aiming to push it to maybe 15:1 if able, limiting factor being piston slapping the cylinder head! BTW I'm glad you mention it but IMO you don't stress just how dangerous/damaging pre-ignition is, knock is hurting power but not the engine, but pre-ignition when there's downward explosions hitting the upward piston as it's nearing TDC is so much worse than knock, I wish I knew that knock was more likely to occur first but don't know 1 way or the other, would love to hear if you do!! Thanks for the great video, when I get to doing mine I'm going to start with a slightly retarded timing to see if it out-performs the oem-spec timing, and go from there til near-optimal (I wouldn't try finding 'optimal' since it inherently means going 'too far' and reaching the point of pre-detonation, will retard it a lil and check, if no improvement I'll begin advancements -- thankfully my platform is a popular one and 20thou off the key is a 'standard' so I know "the range" and would probably begin trying a 5deg advancement and seeing how it went ;D )

[@joescissorhands141]

BTW was nice seeing the man behind 49ccscoot, have been finding I'm watching (and Liking, of course!!!) so many of your videos lately, it's ridiculous but the "lay chainsaw-performance-mech" is SOOOO off-base, I can show you youtubes of "pro's" advising people to put 1/2" holes in the rear of their muffler, by exhaust flange, "because it cools & breathes better" (obviously ignorant to the fact that a 2-stroke inherently has a phase during upward/compression stroke wherein muff pressure SHOULD be above cylinder pressure, you scoot guys have piped exhausts so it's easy for you guys to see & exploit, but in chainsaws guys usually just make big holes!) Funny enough, thanks to watching these non-chainsaw videos, my 1st "original idea" enhancement to an aftermarket, high-flow muffler, it just netted me nearly 20% power because I added a plate that redirects exhaust-pulse right back at the exhasut-flange...lil chainsaw muffs don't have the space for the neatness you guys can do, we basically just do '2 part mufflers' where exits are on front half and rear half is the 'working portion' of the muff, capturing the exhaust pulse & holding it for partial-reuptake!! Thankfully for me I can just take a large log and do before/after cuts, which I literally just did w/ my novel muffler approach because I know people on teh forums won't believe the gain I got so I re-did it and filmed it, but yeah it's so easy to see if something made a 5% difference when you're cutting a log that takes 25sec to cut and you do 3 cuts and have a cut-to-cut variance under half a sec (ie 20, 20.5, 20.25sec cut times...these are how accurate they are, for instnace my muff made a 20.5sec cut take just 16.5sec, so stoked because it's an older/iconic platform where you'd think "*everythging* would've been figured-out" yknow?) Thanks again for the awesome content!!!

[@49ccscoot]

The more limited the ignition system, the more you'll have to compromise. If you've got an ignition with lots of freedom of adjustment, you can dial in timing for the range of engine speeds and in some cases you can add throttle position to the factors for ignition advance. If you've got a set curve, generally you can just move the whole curve by adjusting base/initial timing. So if you advance it 10 degrees on the low end, it's advanced 10 degrees up top as well. There are tricks like adding capacitors with a CDI system to change the curve, but if you want total control you need an ignition system that allows it : kzbin.info/www/bejne/p3rJZZ-liauYn9k

[@jamest.5001]

What I know about 2strokes,. Oil goes in gas, gas goes in carburator, airfuel goes in engine, power comes out! Haha not totally, but not alot more, I would like to get one to play with! Maybe throw a bigbore cr80 engine on a scoot! I'd love to have gears on a scoot!! But I been thinking about going electric!! I have enough high, extremely high current lithium batteries to build a 32ah 72v battery, capable of a sustained 800amps! And 1600 peak amps, 20 series cells , 4 paralell, that's enough wattage to supply over 18hp, with insane torque! It would be like a supercharged turbo diesel, 16hp engine, a 3kw motor on a bicycle would do 50mph+ so a 16kw motor on a little scooter should do nicely! And should only pull around 600 watts cruising at a legal speed, maybe the variator could be used with a electric brushless motor! That could extend the top speed! While keeping a good takeoff and acceleration! I guess I'll have to keep gathering parts, I was thinking about a e bike or E-cycle build, maybe it's an E-Scoot build now!

[@milo-uy6rd]

I have a 1980 yamaha DT125 that had a bad CDI box, I wired up a Chinese cdi box 6 pin connector with 5 wires, i get bad spark knock or detination on deceleration and inbetween shifts. Is there another CDI Box I could buy that would help? I assume it's because I have a 4T Cdi on a 2T bike

[@49ccscoot]

Obvious answer would be a CDI intended for a 1980 DT125. Otherwise, I'd see if I could find a timing curve from the stock CDI. Then see what matches up. Maybe a service manual would have timing specs? Some cheap 2T CDIs are just flat line timing advance.

[@MrSandRune]

It had been better in 150km\h.I ordred new original motor Peugeot V-Clic gy6 139qmb,for 700 with shipping+tax,530 wich is cheap.New scooter cost 900,so I could get much spare-parts,but didnt.So I have 3,one un-original for 300.Planned to buy original exhaust with egr-connection.To get away high compression sound for bigger cylinder.60cc has begun to rumble in start,and making groove noise,so needs to be aggresivle tuned back both needle and screw.

[@Deathstroke069]

Hey , I really appreciate your work . Could u help me out with measurement from the cable of ur digital direct ? What is the idle voltage of each cable from the ignition system ? White ? Yellow ? And what is the voltage of the regulator coming out on the red cable to the battery ?

[@49ccscoot]

kzbin.info/www/bejne/mKa4dqCafd2rjrs

[@Deathstroke069]

@@49ccscoot nvm I love u

[@simeonspencer9322]

How is advanced spark position found after TDC?

[@jackrutherford-1]

How do you get your 0-30, 0-40 and 0-50 times. Do you have a gps app that does that?

[@49ccscoot]

I'm going to link you to a post that I made not long ago about it so you can have all of the details if you want them : 49ccscoot.proboards.com/post/399164/thread

[@1983bigfrank]

hey scott you seem to be very knowledgeable about engine of the scooter. quick uestion if it quick answaer. my started having hard start, now it has been stalling out, now wont start all but sometimes it will but stall again when hit throttle,cleaned carborator, inside all fuel ways passages and float area. i put clear hoses to gas tank to observe what gas is doning. what i have notice the suction of fuel enter the carb line is not being suck down thru the line into the carbis one thing. but two after keep try start it the carb seem to slow flood with fuel some how then i will drain it because it not burning or starting. is something wrong with the vaccum pressure or something

[@49ccscoot]

Could be multiple issues. If it overfills the float bowl at any point, you may need to check and adjust the float height to prevent that. If it is not filling, you may have a fuel supply issue. If it has a vacuum petcock, it could be related to that. Either a faulty petcock or poor vacuum signal from something like a pinched, loose or cracked hose. Not a bad idea to check the fuel filter. You can also try just removing the fuel hose from the carb and seeing how well fuel flows. If it's slow, try removing the gas cap to see if there's an issue with venting.

[@1983bigfrank]

@@49ccscoot thanks Scott for replying so quickly but yes the new things I have put new fuel filter new lines new petcock but what I have noticed when I take the line off to fill the vacuum pressure it almost feel like there's no pressure pulley the gas down when I'm turning the ignition over that is one issue. But I think reason why it is flooding because a little gas is leaking down a little bit at a time and overtime the float is getting full and it's not doing anything but at times when I spray lighter fluid in the airway it was start right up and sometimes it would cut off and other times as long as I'm holding the throttle it will go

[@49ccscoot]

@@1983bigfrank Do a compression test to be sure the engine is healthy.

[@TheTopCat650]

🏆

[@gregoriobartolini]

I have a Minarelli 70cc with a crankhsaft 39.2 stroke , with what value can i set my MVT?

[@49ccscoot]

MVT says 0.40 for a standard stroke with the DD06 ignition that I have. If you want detailed setup info, watch this video : kzbin.info/www/bejne/gIe9o2pqgdljerM

[@rynairs6855]

Hey man. Dunno if you still read comments on this, but i could use your help. Do you still have a fan for an ac engine and could you try fitting it on the mvt and see if the holes for the screws match? Thanks.

[@49ccscoot]

I used a stock water pump so I figured it should, but I just grabbed a fan from a 1E40QMB and checked. Fits fine.

[@rynairs6855]

@@49ccscoot its all good my fan just exploded

[@49ccscoot]

@@rynairs6855 If you're running the MVT, I'm guessing it's high RPM. Not sure if fans will hold up to that.

[@rynairs6855]

@@49ccscoot what would you suggest on an aircooled engine?

[@49ccscoot]

@@rynairs6855 I don't think there's much that you can do other than try another fan. Maybe a genuine Yamaha fan, if that's not what you've already tried.

[@neco1562]

ZATEN DİSTRİBÜTÖRDE VKUMLU AVANS VAR DEĞİŞİK HIZLAR İÇİN AMA DAHA NAZİK DAHA İNCE AYARLI Bİ SİSTEM OLSA İYİ OLUR.

[@emoh_em_ekat_sdaor_yrtnuoc8618]

I just rebuild a 250cc Polaris trailblazer and have spark, fuel and compression but it’s not sputtering or firing up, is it possible it’s the timing, the timing mark is on the factory marker. It’s been bored out, oil pump removed so it’s premix, completely rebuilt engine

[@49ccscoot]

Make sure it's fresh fuel first and that you are getting fuel on the plug. Could be as simple as being flooded or lean. It can be timing, but most of the time it's something more simple.

[@emoh_em_ekat_sdaor_yrtnuoc8618]

Do you suggest try to put gas in the spark plug hole or running it through the carb for testing

[@49ccscoot]

I usually look at the plug first to see if it's even getting any fuel on it. If you've been cranking it much and there's no sign of fuel, then it may have fuel but it may not be finding it's way to the cylinder. Sometimes priming it will be all that it needs. You can put a few drops of fuel in the plug hole and close it up quick to retry or some prefer spraying carb cleaner or starting fluid through the carb. I've used an unlit propane torch in the inlet of my airbox while cranking it over to get them to start. Obviously do this stuff at your own risk.

[@emoh_em_ekat_sdaor_yrtnuoc8618]

@@49ccscoot I appreciate I’ll let you know how it goes

[@anglofil5489]

Hey, nice video. My bike makes “knocking” sounds from the engine after changing to MVT dd. Do you know why? Is it wrongly timed or why does it knock like that. I don’t think it’s very damageabke because it disappears as fast as I hit the gas. So it only knocks on idle

[@49ccscoot]

My first thought after an ignition install when hearing knock is spark knock or detonation. It really shouldn't do that at idle though. Have you checked your variator lately? If the plastic guides/slides on the ramp plate come off or get worn out, it may rattle or knock at idle.

[@anglofil5489]

@@49ccscoot Well this is a am6 Engine so not a scooter however tho what is a sparkknock? Because dum as I am I installed it wrongly and but it on 0.35 btdc instead of 0.40 btdc. I have a 80cc but with stock stroke so I should be running 0.40 btdc but I did that wrong

[@anglofil5489]

@@49ccscoot do you think that might be the problem?

[@49ccscoot]

@@anglofil5489 kzbin.info/www/bejne/onimZmSjfrasos0

[@anglofil5489]

@@49ccscoot late answer but I discovered the issue and it’s the squish. The squish is a wooping 1.20-1.30mm🤯 when it should be 0.5-0.7mm so almost the double. That is probably the reason it knocks because the fuel makes an explosion of the compression rather than the ignition which will cause a uncontrollable combustion and result into a knocking sound. I took the engine out and got it into pieces the cylinder and piston was lucky in great condition. However tho I don’t really know how to solve the squish issue. I remounted everything but still 1.20mm squish. What is there to do? Cut down some of the cylinder but that would effect either performance or the stroke. Pls help

[@TopGgarage]

Wat size carburetor and jetting you are using on your scooter.

[@49ccscoot]

25mm PHBH. Main jet was around 105-110 with an airbox.

[@TopGgarage]

@@49ccscoot thanks

[@ucenmerenx]

Ignites TDC or ignites BTDC. Which one is better?

[@49ccscoot]

Have you watched the video? BTDC is the usual ignition timing.

[@KXSWORKS]

How do you advance the trigger pickup to advance timing?

[@49ccscoot]

With the MVT DD ignition, you can loosen the stator mounting screws and rotate it. For large changes in timing, you may need to install the flywheel at a different setting.

[@KXSWORKS]

@@49ccscoot can you make a video of it?😁 That would be really helpful for everyone who wants a fast bike on a budget.

[@49ccscoot]

@@KXSWORKS The video that you're commenting on shows the process with the MVT DD and it's the same or similar for any of these racing ignitions. I also have a very detailed MVT setup video : kzbin.info/www/bejne/gIe9o2pqgdljerM

[@hansmarquez]

Can u help me,I'm learning to fix my dio,it's now in 6 pin cdi and it moves backwards,

[@49ccscoot]

So you just installed a new CDI and the engine starts backwards? Stock ignition, aside from the CDI?

[@hansmarquez]

@@49ccscoot I put the gy6 ignition coil and it's working fine on my old 5 pin cdi,but when I try use the 6 pin conversion it start to move backwards,then now I tried again the 5 pin it has some current but having no spark

[@49ccscoot]

@@hansmarquez I'm guessing the 6 pin CDI has a different timing curve that is causing the engine to start backwards. If you have any adjustability, either in the CDI or pickup or stator plate, then maybe you can remove some ignition advance and see what happens.

[@hansmarquez]

@@49ccscoot the ignition timing of 2 stroke relies on the stator pickup distance?and flywheel timing?

[@49ccscoot]

@@hansmarquez Yes, moving the pickup or flywheel relative to each other will change timing.

[@thepreviewchannel6398]

to be safe just tickle the pick up point that's it haha

[@ensarraka]

Hello i wanted some help with this i have 70cc kit on my aerox and stock ingition and it was running and it just stoped and made a noise at the ingition and everyone is saying its off timing i looked everywhere no one can fix it i hope u can help me with it what to do!

[@49ccscoot]

I would start with the basics : www.49ccscoot.com/faq/wontstart.html If it's making a noise at the stator/flywheel then I would check for contact. If it's a noise at the CDI then I'd think either the CDI is bad or wiring issue.

[@ensarraka]

@@49ccscoot i changed the sparks and the carb to opened the topend to see for any crank but no it was in a good condition! So where can i check the cdi?

[@49ccscoot]

@@ensarraka Can't check a CDI without special equipment that basically no one has. Most just replace it to see if it works. Not a bad idea to keep a spare around anyway for that reason.

[@ensarraka]

@@49ccscoot my bike now backfires with the new carb

[@ensarraka]

But still didn’t turn on

[@2strokechris]

how to know if your getting detonation ??

[@49ccscoot]

You can hear it sometimes. You may see "peppering" on the spark plug. Literally looks like flakes of pepper on the porcelain. If it's bad, then you may see engine damage. If you have both CHT and EGT, you can watch for it that way.

[@بيكيتويج]

انا من دوله عربيه اتمنى ان تضع ترجمه

[@mohdhanf8262]

1 question, if i upstroke my 2stroke bike by changing a longer rod. So my factory ignition on the bike will be advance or retard?

[@49ccscoot]

Manufacturers tend to recommend less advance with a longer stroke, but you can see exactly how timing changes at any given position with the piston position calculators here : www.49ccscoot.com/calculators.html

[@petewain61]

Hi,it’s pete again from the uk,you have got me so interested in these type of bikes that I have just gone out and bought an MBK nitro 50 two stroke,the fireblade and my aprilia adventure bike have been moved to the rear of the workshop along with the motocross bikes,I haven’t worked on a 50cc two stroke since I was 16 some 45 years ago,I’m going to modify and rework the engine so I might need a bit of advice from you!,in return for the advice I can make you some parts that you might find difficult to do,(I have milling machines and tig,mig and gas welding equipment,large lathes Ect)you could email me the drawings and I can make the parts and get them too you in a few days,how do you feel about that,regards pete

[@49ccscoot]

Hey Pete. I don't expect payment for a bit of advice. I may take you up on parts someday though. Who knows? Anyway, you may also want to join the forum if you haven't already. Lots of smart folks there gladly giving out free advice and it's easy to track a build with your own build thread. 49ccscoot.proboards.com

[@petewain61]

49ccScoot thanks for that,but any parts you need making,let me know,like the footrests I could make them in minutes,I can give you my email address but I’m not sure how to do it without everyone seeing it,pete

[@49ccscoot]

@@petewain61 That's again where the forum would come in handy. Very easy to send PMs.

[@petewain61]

49ccScoot is the forum on your website

[@49ccscoot]

@@petewain61 Yeah.

[@flyboyfs]

Hi, nice work, one question wean you mean retard inition you mean rotate stator anticlock and advance inition timing anticlock wise ?

[@49ccscoot]

Stator clockwise to retard timing and counterclockwise to advance. It will vary depending on the engine configuration (direction of rotation and which side the stator is on).

[@flyboyfs]

@@49ccscoot Thank you, i also have other question regarding on site calculator on degrees from TDC to piston and piston position to degrees from TDC, wean i place inputs and must i use , or . ? Eg. 3,5 mm or 3.5mm , cause it changes final data?

[@49ccscoot]

@@flyboyfs Use a decimal point (3.5mm).

[@pepperjackshack2439]

So the slower the engine the more retarded it should be? OEM manual says -8°@2KRPM. What’s 800RPM setting? -8? -6? 0?

[@pepperjackshack2439]

4 stroke

[@49ccscoot]

@@pepperjackshack2439 An 800RPM setting could be anything. Could be a flat line the same as the base figure given at 2000RPM. Could be retarded to make starting easier. Could be whatever they wanted to set it at.

[@neco1562]

FİZİK DERSİ

[@arthurorcena8943]

If timing was retarded fuel air ratio must be adjusted richer for faster combustion

[@neco1562]

MOTOR LA SENKRONİZE ŞEKİLDE AVANS AYARI YAPAN BİR CİHAZ YAPILMALI HIZA GÖRE DEĞİŞK ZMANLAMA YAPMALI.

[@neco1562]

TERMODİNAMİK DERSİ GİBİ OLMUŞ BİRAZ

[@joshuaharrison9331]

make a dyno?

[@49ccscoot]

I was thinking about it for a bit, but never found any simple and cheap source for a roller near me.

[@flyboyfs]

Nice work, I just finished my bike dyno ana now I am playing with PVL programable ignition and have done some testing new map timings

[@csb772]

So I took your advice and I threw a rod thru the roof of my garage. You wanna help pay the charge.

[@49ccscoot]

I didn't advise that anyone changes anything. I shared my project and some knowledge about the subject. If you get into an accident, are you going to blame other people that you've seen driving or that you learned a few driving facts from?

[@csb772]

@@49ccscoot I didn't blame anyone. I asked if if you wanna help pay for it.

[@49ccscoot]

@@csb772 I've got a shelf of destroyed parts from learning and testing things to try to help others. I've paid my dues in broken parts and then some.

[@csb772]

@@49ccscoot Any Honda Shadow parts?? I need a chain and sprocket.

[@49ccscoot]

@@csb772 I've got a bent valve from a Yamaha if that helps. Not many four-stroke parts anymore.