Yamaha TRX850 Enthusiasts Forum

Following my first ride with the Ohlins rear a few weeks ago, I did a full re-check of my suspension sag & settings, adjusting the compression & rebound dampening front & rear to a theoretical road/sport set-up starting from zero's again.

I hadn't realised before, but it seems the standard R1 springs are 0.75kg/mm which I think is the same or slightly stiffer than standard TRX springs. Even so, my standard R1 fork springs are still preloaded right in to 3rd mark from the top to get the right sag. I'm 87kg with gear.

But when I went to adjust the from rebound dampening, the screws were jammed tight and will not budge at all. I've pushed the cable tie a long way down the bottom tube previously and am wondering if I've damaged the damper rod bottoming off a wheelie or from very hard braking.

To get the right f/r bias on the rebound looking close to correct I had to wind the rear rebound up to 50/60 clicks, so the fronts must be jammed near maximum.

Also increased the psi in the Pilot Powers from 34 to 37 (F) and 32 to 35 (R).

Anyway, out for a very spritely run through the hills with a few local 'rocket boys up here. The new settings are definitely sweeter at the lower end of the spectrum. The slight (but annoying) fore/aft jigger at traffic speeds is now just more of a balanced firmness. Probably as good as I can expect with the softer standard front without compromising handling. Tight bends are even easier than before... touching down earlier and sliding longer, able to change line on the deck reasonably comfortably.

But... at the higher end of things on typical roads, the steering dampener starts wanting more clicks once a certain speed is reached. Rather than just stiffen things and keep pushing, I prefer to slow down and sus' the cause.

The very next thing I'll do now is get a set of 85nm fork springs (matches the rear spring) and see what's going on with the dampener rods.

Why the steering damper?
I would just focus on getting the suspension tune right, without one, then if you must, add one as an extra safety margin.
I ran a revalved and resprung R1 front end (98-01) to suit the different weight bias of the TRX and of course to my weight. The rear shock was also done to provide a matched set up.
It was never anything but composed, even when being stupid.

Not bagging, just curious why you need a steering damper at all, they often mask a suspension or geometry issue.

Understood Stu'. Yes, I see now that my wording there tends to give the wrong impression. The steering dampener (fully adjustable) is actually fitted as a safety measure; not as part of the handling package
Playing with geometry and mixed components, I figured it wise to have the dampener fitted before testing, rather than as a potentially nasty hindsight.
And the fact that I needed it makes me glad it was there.

Good to hear the positive results from your setup. It confirms the likelihood that my planned actions will get it sweet & smooth as it should be in all conditions.

Ok, I see. Makes sense now.
The std R1 forks are too soft for the TRX. The R1 spends most of its time trying to lift the front end, whereas the TRX loads it a lot more. Also why the earlier R1's ran a little more fork travel.
I think you will be amazed at the difference the firmer spring will make, especially if you revalve to suit.
BTW what year model front end are you using?

Same as yours Stu'; 98-01
I've heard the early R1 forks circuit needs to modified as they can't be re-valved. Is that right? What sort of $ do you reckon?

Ummm... hopefully without winding anyone up, mind if I inquire into rider's weights? I weigh in at 81kg and the R1 front seems to be pretty well set for my weight as it came. Wouldn't R1 put more weight on the front wheel being a 4 cylinder? Thought the R1 was also about the same weight as the TRX???

I had my 99 front end rebuilt to suit my weight and revalved to suit the trx with gold valves on the rebound and compression side of things.
0.9 springs are Inplace for my weight at 80kg and bike weight at 190kg wet with 5mm shorter dogbone to favour a little more front bias. (23.5* compared to 25* std Trx spec)

I know what you mean Brett with the rebound onThe Ohlins.
I wondered how many positions there where from from a full rebound/ clockwise position and it just kept unwinding so I stopped after 35.
It's been sprung to suit my weight and found 10 clicks out was a good starting point for the rebound.
I placed a small silver dot on one of the recessed grooves on the hydraulic preload winder as a marking point so if you go two up you have a reference point.

QuickDraw wrote:Same as yours Stu'; 98-01
I've heard the early R1 forks circuit needs to modified as they can't be re-valved. Is that right? What sort of $ do you reckon?

I just talked to the guys about my application for the R1 forks, my weight and riding, then let the experts go about changing the springs and modifying the internals to get the results I wanted.
I think from memory it cost me around $500 or so and I was very happy with the results.

For the sake of comparison, I rode the R1 forks in standard guise for only a few rides before getting them modified.
As std they felt soft, dove way to much under braking and lacked the damping control in corners with the odd bump. Hence, didn't ride them too hard cause I knew they needed work.
After mods they felt solid and controlled in all situations, couldn't fault them.
Just my humble opinion.

davamb wrote:Ummm... hopefully without winding anyone up, mind if I inquire into rider's weights? I weigh in at 81kg and the R1 front seems to be pretty well set for my weight as it came. Wouldn't R1 put more weight on the front wheel being a 4 cylinder? Thought the R1 was also about the same weight as the TRX???

The engine weights are almost the same despite the R1 being a four banger. The overall bike weights are pretty close too.
However, versus the TRX, the R1 made 150hp so spent a great deal of time trying to lift it's nose skyward, so was comparatively softer sprung and had a longer 135mm of travel.

I had mine modified for 110kg with gear.

Hey Brett , did you say you had 180mm dogbones that where 2mm shorter than std???(182mm)
What bike where they off???

That's right Cobba'. They were already fitted to my bike when I bought it in 2001. Alloy units. From a ZX-6 I was told.
They made about 10mm difference to the ride-hide if I remember correctly.
I'd be happy to swap for a set of standard ones if you're interested in them. Otherwise I'll just bolt them up on bike #2 (one of these days!)

...when I went to adjust the from rebound dampening, the screws were jammed tight and will not budge at all. I've pushed the cable tie a long way down the bottom tube previously and am wondering if I've damaged the damper rod bottoming off a wheelie or from very hard braking.

The very next thing I'll do now is get a set of 85nm fork springs (matches the rear spring) and see what's going on with the dampener rods.

Well, I got some .85kg/mm Racetech springs at the right price, figuring that rate would be close enough. I was set to go the Gold-valves too but $ were shy so I decided to sus' the problem with the rebound adjusters and just replace the oil with 15wt to compensate for the extra dampening required with the spring-rate increase. Not very scientific, but on first short ride, so-far-so good. An ordinary sort of wheelie-touchdown only the pushed cable-tie marker down 35mm from static sag height.

Curious thing when setting the sag; despite the heavier springs, the preload adjustment required to bring in to range was the seemed slightly more than with the standard springs. Maybe I made an error last time.

As for the stuck rebound dampeners; I thought I had adjusted those previously. But I must have been mistakenly thinking of my other forks (or maybe just Boobs... who knows) because when I lifted the caps for the first time, they were bottomed on the shaft thread with the lock-nut... Someone previous had taken it all apart and done it up again without setting the 17mm clearance needed for the adjuster-screw to contact the plunger rod correctly. So the plunger was jammed down past maximum as soon as the fork-tube cap was re-installed. Easy fixed. Clearance set. Working nicely now.

...at the higher end of things on typical roads, the steering dampener starts wanting more clicks once a certain speed is reached. Rather than just stiffen things and keep pushing, I prefer to slow down and sus' the cause.

Going over the bike, I found 2 other issues which I think had more to do with my wobble.
1. A whisker to much play in the steering head bearings
2. A front tyre worn wonky. Check the picture... normally being a careful sort of fellow, I ride to a clear line of sight. With more available on right hand bends, I can go harder with lower risk. In the lefties I can't see as far, so I go a little easier. As the tyre wears, the profile adapts to this habit; encouraging quicker tips to the right and giving a bigger contact patch, which feels better, so I go faster, and the tyre wears righter even more, and so it goes...

...Until, the tyre nears the end of its life, by which time it has worn very unevenly to one side, moving the profile apex off-centre to the left rendering things more liable to more wobble action in stand-up & go-fast mode. All that said, to confirm that theory and test properly, I'd have to run with the old springs. And I'm not doing that of course.

Now - the twist;
While the initial feeling is good, I was hoping to tell you how perfect it is (or isn't) all-round. But I can't yet because...

I chucked it out of a roundabout. I had "new" second-hand tyres which are perfect. But remissively, I failed to de-wax and buff them. (But they'd already been used right?) Yes, BUT not enough to scrub them in. My stupid assumption has put me back to the workbench for a while.

Anyone with a spare left hand:
- alternator cover
- rearset with selector rod
- pillion peg hanger
- standard exhaust can (not mint, suitable for cutting)
that they'd be happy to sell... please PM me

Bummer Brett, that really sucks.
I hope you faired ok from it??
I have all you need apart from the exhaust so we can get you goin tomorrow as we will be heading your to the Sunshine coast tomorrow.

Awesome! Thanks Brian. See you tomorrow!

'thought I'd show a bit of an update on my repairs.
Always one to try and turn a bad situation good, I took the opportunity to do up some other second-hand damaged tanks and panels had.
So I'll end up with a brand-new full set of blue for the other '99 model I have disassembled, plus a spare set to keep (which I'll be keen to never need! )

• • dents a pulled with spot welded studs

• • light use of polyester filler has restored finished shape up nice. It's a lot of work hey. Dusty & tedious. Panel beaters ought to be paid better I reckon!

• • little bit of plastic welding with an electric soldering iron went well

• • bare plastic sprayed with adhesion promoter, old paint sanded and sprayed with isolator (metho based, not fun either ) before hi-fill primer, to prevent the metallic lacquer base wrinkling any old enamel that may be still there

So it's taking a while, but hopefully only a few more weeks before I can get mobile again... just in time for the perfect riding weather.