Posts
333
Joined
10/15/2011
Location
NC
US
I usually go 50-75 hours on a yz piston without any issues because I'm a jetting, air filter and maintenance freak. This time in my 2016 I decided to stretch to 100 and see what happened..... Holy hell I'm lucky! The crank and cylinder are in great shape though.
The Shop
We have seen many, many YZ transmission failures- and not just the run of the mill worn out engagement dog.
We have seen many instances of broken off gear teeth which then got wedged between the shafts, and several cases of a gear shattering into pieces which then wiped out the cases- even on very low hour bikes. This points to a fundamental metallurgy or heat treatment problem. Combine this with a weakly supported 4th gear, and the YZ gearboxes are a real Achille's heel.
They shift well, but gearbox durability is not a YZ strong point to put it mildly.
Top ends are cheap and its only 2 hours I would have just wasted looking at smut online anyways. 100 hours?? No way. Even 50 is a lot to me. Theres a reason the owners manual says 15 hours and its not because they were designed to last 100.
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