Gearbox Failure: Oh dear! What's that noise?
 

The gearbox on my tenere failed at just 27k...

Without any other previous symptoms, I started hearing some rattle while waiting at a red light while the transmision was in neutral. It stopped and rode home without any issues. Next morning I started the engine and while putting the helmet i heard the rattling again... on the road to the dealer it felt like at certain times the transmision was about to slip out of gear while riding constantly at 3k rpm... ironically when i was trying to show the mechanic what the symptoms are it all went smooth for about 20 mins - finally, it started again but this time it was on centerstand so i could see better what happens: bike out of gear, at around 3k rpm it seems like it couples first gear for a fraction of second, rattles and moves the sprocket few degrees...

Bike is left in the shop to open up the gearbox...

I haven't abused the bike much, changed the oil at every 5k and it seems to me a bit earlier for the gearbox to fail at just 27k under these circumstances... any idea for what might cause it?

oh dear! what's that noise?
 

well to cut a long story short my tenere is in the sick bay, ICU in fact

a month or so ago i was in the south of france doing a week of fairly rough offroading, towards the end the week the gear selector would just jam up neither going up or down the box, fiddle the pedal a bit and it would come fine. so i thought the selector has had a bit of a tweak on a rock etc.

anyhow it got me home fine and back to the usual commute. sarah and i went for a spin today, thankfully we didn't get too far. a crunching grinding noise started on a up change from a junction and loss of drive. ho hum,

on getting it home[trailor] and pulling the clutch basket i have found a part of a broken gear in at the selector drum/ mech [looks broke a while] so after dinner i need to pull and strip the 33,000 mile motor

more fun to follow

Not good news mate. Keep us all updated.

Bad news fella. Will be interested to hear what's inside the cases.

not only does that sound horrible it also sounds very expensive

hope the cure is not too crazy money

hi, at long last the motors mostly stripped, There seems to be a few issues going on

firstly when pulling the head down i could not believe, the cam was out a tooth, on inspection the tensioner was out to it's last hmmm, with the head and barrel off all became apparent. the timing chain guide[intake side] pivots on a imo flimsy metal bracket which had disintegrated allowing the guide to move up as well as rubbing the back of the chain. not an impressive design!

next the gear stopper bearing has collapsed, this hold the gear selector drum from rotating freely, it kind of indexes it to a set gear. i'm guessing with it being fecked it has allowed the gears to 'auto' change.

the elephant in the gearbox, well thats obviously knackered. it's the '3rd pinion gear', a broken bit has damaged the '4th wheel gear' [yamaha manual names]. so will get on to yam with my list of bit and bobs and all will be well again. hopefully!

http://i192.photobucket.com/albums/z...amily11528.jpg
.

Not good news, have seen this before.

Crikey Kev, I hope you haven't seen it too often. I was under the happy delusion that these engines were all but indestructible. Another belief down the drain. Sigh.

I am sorry to hear that you've been stuck with this badness, stoic bloke. Sucks.

but not Stoic-proof.

Remember this enginge has been pushed hard, and Bernard is a demanding rider, and while I'll stop short of saying he is some kind of 'motorcycle murderer', the bike/engine has been raced from Paris to Dakar (when other more 'germanic' breeds were failing), as well as the daily commute and other long distance trails - so if it's going to fail, it's going to be this one!

This is number 3 I know of, but the first XTZ out of thousands of XT660 over the past 5 years, so nothing to worry about.