Yamaha TRX850 Enthusiasts Forum

Hey all.
I recently had an r6 with the adaptor thrown on (cheers Cob ) and it's lurvly, but now when I take my hands off the bars at about 80Kmh it develops an increasingly violent headshake. Here's the twist... It may be due to the fact that some tool knocked my bike over the other night (likely some drunk cock) and it fell to the right, onto grass. So I guess what I'm trying to do is eliminate one of those as the cause of the headshake. Has anyone else had it happen after installing a r6 shock? do people usually mess with the amount of fork through the bars when they throw one on? Or is it more likely that the forks are slightly twisted in the triples? The bike tracks true and doesnt feel any less willing to turn in either direction.

Running dunlop Q2s at 34/34 (160/60r and 120/70f)
r6 shock/adapter
stock forks pushed through +/- 27mm

Check your tyre pressure first..

alextrx850 wrote:Check your tyre pressure first..

Yeah, 34 psi each. Does that sounds OK for Q2s? Although I cant really vouch for the accuracy of caltex guages. lol

jim280885 wrote:

alextrx850 wrote:Check your tyre pressure first..

Yeah, 34 psi each. Does that sounds OK for Q2s? Although I cant really vouch for the accuracy of caltex guages. lol

Yep, 34 & 36 here (but I guess riding style & weight would have an affect ) My fork aren't dropped through though.

Steering head bearings would be the next to check.

It's unlikley that your forks are twisted or any other damage has occurred or you would have problems at all speeds (but check anyway - easy enough job)

By changing the rear shock, you have altered the geometry of the bike. This combined with the wear on a 60 profile tyre (I'm amazed people still buy these) is your likley culprit.

Yep, the trx is renoun for stability..it would have to be the front tyre...and the feedback from it, the head shake would be initiated by the front rubber...if it is still happening, you are going to have to supply more info.

Pull the forks back to 18/20 mm around std setting Jim and start from there . If no luck Check there is no twist as who knows whats happened when the bikes gone over and where the dude landed or how heavy they where.

Balance weight fell off ?

If its fallen with the handlebar pushed forward away from the tank, the front wheel would be facing up too and if some clown has fallen himself onto the front wheel you have a good leverage factor and possibly one fat f$@k to twist things...

Perhaps loosen off the pinchbolts on your lower triple clamp.
Roll her forward at pace and grab a handful of front brake.
This tends to align the front back up.
Then re torque the lot.

cobbadiggabuddyblooo wrote:If its fallen with the handlebar pushed forward away from the tank, the front wheel would be facing up too and if some clown has fallen himself onto the front wheel you have a good leverage factor and possibly one fat f$@k to twist things...

AND then, if ANOTHER similar clown tried to help the first one up..and so fell because of a Banana Skin conveniently placed by the first....and landed on his squeaker horn and the handlebar that was pushed forward away from the tank.....THEN you would have a good leverage factor...honk honk
Don't get me started on sqwirrels

Wicked boy!

Hahaha, Alex. Thanks for the quick responses guys. I'll try that advice of loosening the lower triple off a bit etc. and play around with tyre pressures too.

thanks again.

Tyre pressure if that does not work maybe look at a different brand of tyre/tyres
Or maybe the tyres you have fitted are from India.

Need more pre load on rear shock