Lightening the flywheel

JUst wante to know if anyone has this mod done to their 50 and if it was worth it. CAn this be performed in a garage or does the lightening need to be perefectly balenced? :excuseme:

It will make th engine rev faster because there is less weight to rotate. This also means that you will have less top speed depending on how much you take off. It should be done by a professional with the right tools to make it perfect. One option is to send it in to bbr they can do it for 89$ i recall.

its not worth anything. no noticable difference at all with auto clutch, maybe better with manual.

i got 8oz taken off buy rath racing here in town and it defently revs alotfaster and i can rev out 1st and click 2nd and snap the trottle and the front end come right off the ground

you say that like it didnt before lol

I made a "total loss" ignition system for my ATC 70. This does away with the flywheel and it's unbelievable how quick it revs. Removing the flywheel took off about 2 lbs. of rotating weight.


i wanna hear more.

inner rotor kits are big $$

Yeah, I guess you could say "made". The only negative is that you need a battery. I used one from a scooter.

I drilled the rivets out of the flywheel assembly and used the hub. This hub has the cam that opens the points. Hot side of the battery to the points and ground the negative as usual. This setup gets the power from the battery instead if the magnets and coil, loosing all of the rotating mass.

I could run for about an hour before the battery needed charging. This system was on my Blown Alcohol ATC 70.

gotta say thats real ghetto, battery powerd and whatnot..

id run that 70 motor tho! that blower give much gains or dd it just kill the lowend and make the topend nuts?

I wouldn't really call it ghetto. This was before electronic ignitions were on the little singles. It removed alot of weight from the crank and also made a spark that was about 10 times better. It ran good with the stock ignition but when I went to the total loss, the gain was huge due to the more complete burn of the alcohol.

The blower added power every where. You have to think, this was built before you could get any aftermarket parts for these little singles. Almost every part in the engine was either hand made or had many hours of machining done to make it work. All of this was done because someone said that I couldn't do it.

It was between 13.5:1 and 14:1 and 16 lbs. of boost. I ended up putting a Tillotson carb on and that worked out better that fooling with jets on the 110 carb. I TIG the exhaust from 1 1/8 ID stainless.......

Way too much work, but it is the coolest!

I might try that if I had an old beater or something like that. I have two bikes. One is REALLY nice and the oter has CDI so that is not possible for me. Post some pictures maybe of the stuff under the cover. If possible, make a movie or just audio or something to hear the engine.

Wait a second. ATC70s have the pull starter on the left side. The recoil thingy is mounted to the flywheel, right? If so, how do you start it? There is no flywheel.

After you remove the flywheel, you're still able to bolt on the cage that the starter dogs engage. I'll try to send you some pics of it.

Okay. Cool.

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