Hey Guys
I have recently had a transmission failure for the second time on my 2010 CRF450X the first time was fair enough as i had it wide open on the bitumen and clicked 5th gear without the clutch and it went bang, and wouldn't hold 5th gear just jumped in and out of gear, i was still able to ride it home as no other gears were affected.
Once i disassembled the trans i found a fair peice broken out of the shift drum right at the end of the groove, i replace the drum about 3 gears due to wear on the dogs all the forks and every bearing in the engine/trans plus clips and thrusts. Now about 2 years later and not a whole lot of hours its gone again on a mx track after a jump it seemed to go into neutral so i went to select a gear a bang rear wheel locked solid engine continued to run on disassembley ive found another failed shift drum but this time alot worse,
What i would like to work out is this a result of the dogs not engaging correctly and jumping over each other and driving the fork back into the shift drum coursing the failure?
Am i to hard on the gear selector?
Or if u have a good look at the photo of where the shift drum has failed could it be a manufacturing/design fault as there is no material at all where the cracks started?