So I installed the Athena 170 kit. And after tuning the carburator, i took it out for a top speed run (148kmh in gps). The front sprocket 17 made the bike much more enjoyable, power wheelie in 1 & 2 after shifting. Overall great fun. So i decide to go on a late night drive for fun .
On the highway at +- 120km/h I lost 6th gear . So i put it in 5th gear, i was just at the exit i needed so i slow down, try to give it some gas to get of the highway but after 50m the gears dissapeared. Still 1 of 2 gears somewhere when standing still, but didn't drive it home.
6th gear always sounded different than the other gears ever since i bought the bike 22.000 km ago, the added torque probably pushed it over the Edge.
So I was wondering if anybody has an idea on what to look for when in open her up .
Or if possible, some tips on where I can get reliable original parts or if there are reinforced kits I can order?
Calum last edited by
I somehow doubt you've damaged the actual gearbox. The cogs are knarly stuff and can withstand a lot of punishment. Typically there is not any movement between the cogs, therefore it will withstand the torques applied to it.
It is more likely that the problem lies else where, dog ears, selector drum or merely the clutch basket.
First point of call though is to drain the oil and see what comes out.
Whip the clutch cover off and investigate any abnomalities behind the cover. If that looks okay then drop the engine and split the cases.
Thanks, i'll keep that in mind. Gonna try and get a first look today.
Check the woodruff key on the crank primary drive cog
So i started opening her up. Everything looks fine gearbox wise this far. I'll split the case asap but I have to wait for a flywheel puller or ask my local Yamaha dealer to pull it for me.
Pulled the Athena 170 cilinder and head, both are already damaged. No clue why. Bottom ring is completly stuck, also explains why it had very good compression (full weight to kick it over) after the first testrun +- 10min it was 10 times easier to kick over.
This looks like an overheating issue? But shouldn't the damaged be at the exhaust side
Calum last edited by
@llldennis I was going to say overheating as it happens. Could have been inadequate lubrication
If it was only one side I'd say bent rod, what was the little end bearing like? And what does the plating look like near the transfer ports?