08 R6 high speed compression still just for show?

[SPP]

Ok, I'm on a new (to me) 08 R6 and am having a fiddle. This model comes with high and low speed compression adjusters.

Does anybody know if the high speed compression adjuster on stock forks and shock actually works now?

I read RTs suspension thread 2007 which I almost understand. In one post he mentions an R6 (assumed to be 06 or 07) and that it's HS damper worked by preloading the shim stack. The LS compression was a common bleed needle.

The problem with it was that the shim stack didn't open far enough when the LS was any more than a half dozen clicks out rendering the HS adjustment next to useless... or something like that.

So, did Yamaha sort it out with the next gen (08+) or is it still as useless as the previous years. If it is useless, what where it the best place to set and leave it? opened up fully (least preload on the stack) or set midway or...?

[Robert Taylor]

Ok, I'm on a new (to me) 08 R6 and am having a fiddle. This model comes with high and low speed compression adjusters.

Does anybody know if the high speed compression adjuster on stock forks and shock actually works now?

I read RTs suspension thread 2007 which I almost understand. In one post he mentions an R6 (assumed to be 06 or 07) and that it's HS damper worked by preloading the shim stack. The LS compression was a common bleed needle.

The problem with it was that the shim stack didn't open far enough when the LS was any more than a half dozen clicks out rendering the HS adjustment next to useless... or something like that.

So, did Yamaha sort it out with the next gen (08+) or is it still as useless as the previous years. If it is useless, what where it the best place to set and leave it? opened up fully (least preload on the stack) or set midway or...?

We actually used the high speed function on the front forks as a tuning aid on both Midge Smarts and Jaden Hassans Superstock title winning R6s. Primarily for tuning brake dive resistance according to track conditions and available grip, we call it a ''slope adjuster'' as it manipulates the angle of damping force build up .With standard shimming and base preload on the valve body the response range is not where we wanted it and to set it up properly requires a very pedantic approach with reshimming. But further to that we replaced the base compression pistons with high flow Race Tech pistons. Absorbing abrupt bumps and not asking too much of the tyres to do so is still just as important on track!
Also the bypass passage through the centre of that valve body is very long and very restrictive. That means it cannot pressure balance quickly on stroke reversals giving a lag in damping response. To a rider it lacks feel. Also its worth ditching those old technology checkplate type midvalve pistons and fitting Race Tech ''bending shim stack'' midvalve pistons. Damping response and control is improved dramatically.
The response range on that adjuster is dependent on how aggressive or otherwise the shimming is, how restrictive the pistons are and how much preload exists on the poppett spring even when the adjuster is fully backed off. Given that the pistons are restrictive ( as are many aftermarket pistons ) the high speed adjuster needs to be backed off fully if you still want some faint vestige of bump compliance.
With respect to the rear shock the jury is out on the effectiveness of that ''adjustable dump valve'' We had it wound a long way in after a lot of testing to achieve a decent modicum of rear ride height control on track. On the road you could try opening it out further to test its reactance to the same series of nasty bumps at various openings. The price you pay with such a crude high speed adjuster is that it also affects dynamic ride height control.
Compression adjusters in a conventional piggback or hose reservoir ''single tube'' shock are in effect an adjustable ''gate'' into the reservoir. But it must be remembered that flow into the reservoir is only that of oil displaced by the shaft. Thats only 12 to 13% of total damping force.

[SPP]

Thanks for your time RT.

For the fork, I’ll back off the HS adjuster for now and leave it alone.
For the shock I’ll set it to out-of-the-box and then have a quick fiddle.

Ah well, at least "four-way adjustable" still sounds impressive even if the reality is somewhat meh