A forum for owners of Yamaha TTR250 trail and enduro bikes!

Markvan · Guru

Starter motor teeth , idler gear teeth , sprag clutch

Cubber · Super Guru

Starter motor teeth.

TTRfan · Super Guru

Martyn is absolutely right. If you use that starter it will almost certainly damage the teeth on Idler Gear 1. You may be lucky and the gear on your motor is still OK.

It looks as though the sprag clutch has allowed a kickback that has taken the teeth off one side so it is likely that the sprag is toast as well

Don't throw the starter away as the brush set, O rings and magnet body might still be useful spares wink

Brian

Markvan · Guru

Thanks for the that. I wouldnt throw it away. If starter or sprag clucth went on my TTR i would have the items removed and use the kicker. Hopefully thats many years away.

Markvan · Guru

RE: Starter motor teeth , idler gear teeth , sprag clutch

Markvan · Guru

Hi Brian again please. If you can advise me , Im thinking sprag clutch (only abit worn ) , small idler gear. (Good ) , large idler gear (abit chopped up) from the rough starter motor teeth photo. Can put up more photos if needed. Thanks. (All parts from a blown motor i got ). Thnx.

-- Edited by Markvan on Sunday 6th of December 2015 01:42:28 AM

-- Edited by Markvan on Sunday 6th of December 2015 02:06:44 AM

TTRfan · Super Guru

Small idler looks fine. I would bin the larger gear and sprag.

The sprag has already caused damage and the teeth on the large starter gear need to be perfect else there is a good chance it will damage the starter pinion.

Brian

Markvan · Guru

Thanks Brian. i looked harder and found the posts saying teeth hav to be perfect. Have a totally hypothetical question. "A kick start only TTR." disregarding all the electrical , just all the mechanical cogs removed for the electric start. Starter motor removed, small and large idler gears removed, does this big "ring gear thing " cog have to stay on behind the magneto, would it make the motor rev quicker if removed , alot of weight in this big cog, a spacer could be made , or even cut the teeth and metal from it. Or does the engine need this weight for part of its inertia revving.

TTRfan · Super Guru

As far as I can see the largest starter gear can be removed. The flywheel fits on a taper so doesn't need it as a spacer.

The gear freewheels when it isn't being used in starting the engine so it won't make any difference to acceleration etc.

Still wouldn't want to be without the e-start though wink

Brian

Markvan · Guru

Thanks Brian. i know what you mean now. Freewheels on those small bearings, only spins when starter motor engaged.