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Tr280 Transmission Clicking


sask_skill
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Hey I bought this bike in spring which is my first trials bike and I love the sport but I feel that I bought the wrong bike.  After a handful of rides the bike started clicking while in gear, almost as if the bike wants to shift up.  Even in neutral the bike clicks if you spin the countershaft.  I removed the transmission and found some gears worn down and a chip off another.  I sent the transmission to lewis sport but after a handful of rides it went right back to the same problem but now when shifting it sometimes doesnt click into gear properly. you can move the shifter up and down and it normally shifts cleanly but once and a while it gets stuck and you have to shift back down and up again or else the shifter just moves up without doing anything.

When looking at the transmission I cant find anything noticeably wrong, their is a very small amount of wear on the shifter drum where the idler wheel rolls on it but thats all I can find. Also if I remove and install the gearbox the problem will go away for about 5 rides.  Any help would be great! I love the feel of the bike when its working but I cant take this anymore and I don't want to sell someone a junk bike like the previous owner did to me.

2012 ossa tr280i

Edited by sask_skill
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The problem is likely to be the primary gear shaft moving out from it's LHS ball race. I am not sure if the 2012 bike has a bolt with left hand thread to keep the shaft in it's correct place in the bearing, think this was introduced for 2013. You would know if your motor has this bolt, it exits through the clutch centre hub. If there was no bolt, then the clicking problem is caused by the shaft moving away from the LHS bearing. The problem would show up some time after the gearbox was working perfectly well and then get worse. Previous to the through bolt, there is nothing to prevent the shaft from moving out of it's LHS bearing, which can cause random gears to mesh with dire consequences.

To fix this problem, strip out the gear cluster leaving it in gear to do so, not neutral. Clean the oil away from the primary shaft crankcase side bearing, on the primary shaft end, use a small die grinder to grind in about 6 dimples into the radial surface of the shaft where it fits into the bearing. This is to provide a "key" to allow loctite to bond to. Use a blue loctite 243 on this surface (after de-greasing first) when re-assembling the gear cluster.

Alternatively, if your motor has a through bolt, then the problem may simply be the adjustment for the gear selector, which requires the cluster to be removed to get at. Where the selector drum sits on the gearbox plate, the RHS, there is an eccentric pin on a 10mm hex with a lock nut behind. Moving this adjusts the throw of the gear selector one way to another to obtain sufficient rotation of the drum to select gears going up and down the ratios.

Hope this helps, bye, Peter B.

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  • 2 weeks later...
 

Using Loctite works well. I don't think the 2011 and 2012 models were machined deeper behind the bearing to accept the through bolt. Have a look at your crankcase when you do the loctite mod to see if there is sufficient room, the through bolt has a wide flat head approx 4mm thick. Use a de-greaser before loctiting.

Bye, Peter B.

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i think i'll do the loctite method with my 2011.It's not making any noise,but it won't hurt it and i don't have a spare transmission.I might drill a small hole in the plate while i'm in there to aid in complete oil drainage.Anyone have a sugestion as to where to drill it?

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  • 3 weeks later...

Hi ric, you can drill a 4mm diameter hole in the "gearbox plate" the aluminium RHS plate, at the lowest point on the bottom right corner, without this hole, the oil tends to mostly stay in the right side of the gearbox. The factory adopted this mod on either the 2014 or the 2015 bikes.

Bye, Peter B.

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