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Snapped output shaft on KLX300r

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After a couple month build up converting my bike to super moto street spec it was finally ready to ride.

Started bike on the stand all was good switched off and went inside to get my helmet and gear.

When i went to kick the motor over again the kickstart jammed at half stroke, i let it come up again and gave it another kick this time it jammed then sprung free with a loud crunch sound. Tried kicking it again and the kick start was stiff and crunchy.

At first i thought snapped timing chain or sized motor so a quick couple checks and all was good. Popped clutch cover of and found my idle gear was hanging off.

Further investigation has discoverd a snapped output shaft.

I think this bearing was the first point of fail and some of the casing has picked up and jammed between the clutch basket and the idle gear then when i have kicked it my weight has snapped the output shaft straight thru the oil gallery.

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snapped shaft

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Can any1 shed any light on why this may of happened? Mechanic at local bike store believes it was just a one of break as he has never seen anythin like it before.

cheers mike

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Hey lucky you, er I mean lucky us. Mine did the same thing, but mine broke on the transmission side but my bearing looks the same, there was a tooth out of my idle gear and I suspect that that tooth jammed stuff up and when the bike was kicked and you heard a crunch that's when the bearing and shaft gave. How is your case? Mine was fine. Good luck on sourcing your parts!

Just my guess but mine did the exact thing. I would grab a new timing chain while you have everything else off! Those parts are not cheap but you might send your exhaust cam to get the ACR adjusted so the compression is a little easier on the kicking. I am in the same boat plus a piston and I'm gonna throw valves at it while I am at it since I suspect the reason mine was hard to start and thus broke everyhing elses is because the valves were closed up.

(note to self don't give a bike to your younger irresponsible brother)

Edited by grizzlygibbs

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Typical idler gear caused failure.

I doubt the bearing failed. I'd bet that the idler gear snagged on the back of the clutch.

Post a picher of the back of the clutch. Also check the case for cracks.

What year is it?

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its a 97, i have looked over the cases no signs of damage except where the idle gear and clutch gear have been jammed and gouged the case behind the clutch a tiny bit.

There is evidence the idle gear has jammed on back of the clutch but i didnt know if it could of moved far enough to jam and cause the breakage or a foreign part got in there and jammed the gears snapping the shaft then the idle gear hit the clutch.

The bike was very easy to start, first kick every time. Even after it sittin for 2 months with motor out while i painted frame and bought new parts soon as it was all assembled and new fuel in started first kick.

Parts dont appear to be that hard to come by, TT store has all that i need and at about 1/3 of local price here in Australia

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Hard to believe the bearing went before the case but that happened to Grizzly too.

The case cracked on my '94. I have seen pics of several more with the same crack but don't remember the years. Maybe they beefed up the case at some point.

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It started at the bearing bore and went outward.

The new shaft you get won't have the inner circlip behind the idler gear. You have to pay attention to shimming it.

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