Yamaha TRX850 Enthusiasts Forum

I'm 99 percent certain it was coming from the rear anyways. I left my braking very late on the approach to an island the other day trying to prove a point and in doing so got the most almighty chattering sensation I've even known from a bike. Best way to describe it would be miniature version of a rodeo horse movements only 10x faster ? Felt like it lasted forever but probably about 5 seconds worth. What the f**k is all that about ??? Is my rear shock too hard or too soft or maybe shafted ? Bike has done 16K. I have fitted shorter suspension linkage as per YSF750 spec which has raised the rear nicely and lowered the front down the forks by 20mm.

No weight over the rear end, back end skips and hops, try sitting further back on the bike. Do you use the rear brake, and if so hard or just enough to control it, having adjusted the balance of the bike to make it more front end biased you will have to get used to the rear end trying to push the front.

Dave E

I do use the rear but not heavily.
So it's to be expected then ? Bit embarrassing at the time not to mention bloody noisey !

you will never dial this out with the std shock or forks,, , there is just too much dive on the front and could be too much rebound on the back , but if you have the std bits don't bother its impossible too dial out ,,you can only ride as fast as the suspension will allow you are pushing the std suspension too hard . look at the picture above and you can see what you have to do ,, but its not cheap,, sorry if its not what you wanted to here, the only easy fix is to ride slower and within the limits of the std setup plus as above the tradeoff for quick turn in is not enough weight over the rear

Graham,

What gear were you in? Did you drop down a gear...or more? If so you will induce rear wheel lock up (not chatter) on a bike with 2 hefty pistons going up and down! That for me is an endearing feature of a twin as you can use the engine braking rather than relying on heavy brake braking if you get my drift (no pun intended!). I tend to feather my rear brake to help avoid locking the rear too much when pushing on a bit. Only real way to truly get rid of this is a slipper clutch I suppose but that isn't really a viable proposition for many...try using a smidge of rear brake.

I had a Firestorm a while back and that was worse than the TRX for locking/hopping its back wheel due to 2x500cc pistons rather than 2x425cc ones. Once had to bump start it - no hope as a dripping wet 11st person!!

Anyways, hope my 2penneth helps.

Corners (sometimes mildly sideways!!)

Yep sounds about right now you mention it mate. I did drop down a gear just as it happened but I try to blip the throttle a bit to lessen the effect. Can't have blipped it enough eh ?
I'll be ready for it next time.

G Beale wrote:Yep sounds about right now you mention it mate. I did drop down a gear just as it happened but I try to blip the throttle a bit to lessen the effect. Can't have blipped it enough eh ?
I'll be ready for it next time.

Mine always used to lock up with the stock shock if you dropped into 1st or 2nd. In your case, engine braking, plus you've chucked all that weight onto the front, plus I believe you're on stock forks (very low spring rates if standard!), PLUS the stock shock has a s***load of rebound damping and tends to jack itself down and stay there if provoked.

My '954, just like the RC51, had a very weird chassis peculiarity in that it would wave the back end in the air with little or no provocation, especially when you showed it a rippled surface. You'd not even be close to the limit at the front, and the back would get itself about 2cm up in the air and start bouncing off the tarmac and wagging about sideways. Amusing, unless you really were pushing your braking at the front end and the back started to try to pass you. Sounds like you might have experienced something similar...

I've had the rear end doing that a couple of time sin that last week or so. I thought I was maybe grabbing too much rear brake. May have to practice that one a bit. A thought was to feather the clutch while hard on teh front brake. Manual slipper of sorts.

clutch in - blip throttle - clutch out - problem solved,

bernardo wrote:clutch in - blip throttle - clutch out - problem solved,

Should I change gear while doing this? It sounds complicated!

^^^^^^^^^^^^^^^^

I've been getting this rear end chatter under brakes too but its the misses goin "your goin in too fast,watch out for that hole,theres a car coming the other way,I cant do a thing with my hair, oh I've broken a nail"

I'm surprised she will even get on the back, mine was there for 3 maybe 4 minutes when she said the wind in her face was hurting her neck ! We just touched 40mph.

Well I'd only just got outa the driveway

I was still in the garage !