Feedback Sought on Dialing in Suspension

Wanted to get feedback on my suspension settings.  I started by going with HighFive's suggestions found here but felt that on road the front end dove a bit much, and off-road that the rear was too firm.

Please keep in mind my situation- 140 pound rider w/o gear, front forks raised 5/8”, rear lowered by 2” (yamalink+ride height adjustment), rear spring at service manual minimum preload (8.5” shock length), stock trailwing tires, 50% local paved roads, 30% interstate, 15% gravel, 5% dirt.

THANKS!

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Update -

Raised the front forks to 1.25" and installed bar risers, installed T63 tires (which lowered the front by .33").  
Thus front is lowered by 5/8" and rear is 2.0"
Going with 20 psi front, 25psi rear.
Dialed in "X" suspension settings.  Pretty happy now with road use.  Will need to test offroad.
Took 30ml out of each of the front forks as an inexpensive way to compensate for my low weight - rather than change fork springs.

Is that a typo under fork rebound?  Are you beyond the factory range?

The rear spring is most likely to stiff for someone your weight.  At the very least make sure you set your sag.

edit* First you set your race sag to around 4". Then once that is dialed in you measure sag with just the weight of the bike, should be around 1.5" or something I forget the number. The second step determines if your spring is to soft or to stiff.

Yes fork rebound settings are beyond factory range.

Racetech Calculator says I need lighter fork springs and heavier rear spring.

FRONT FORK SPRINGS
Recommended Fork Spring Rate: 0.409 kg/mm (use closest available)
Stock Fork Spring Rate: 0.47 kg/mm(stock)

REAR SHOCK SPRINGS
Recommended Shock Spring Rate: 8.653 kg/mm (use closest available)
Stock Shock Spring Rate: 7.7 kg/mm (stock)

http://racetech.com/ProductSearch/1/Yamaha/WR250R/2008

Looks like you have it pretty close.

Set the sag to 4 inches too, I dont get the 8.5 inch shock length reference.

I'd run the shock rebound in the 3-5 clicks out range so it doesnt kick the rear end up when you hit unexpected things off road, this was my biggest beef with the stock suspension.

Turning the rebound in on the shock also has the side effect of making the compression a bit stiffer so you may have to back the compression clicker out a few clicks when you do this.

I should have said 8.5" spring length. Spring preload adjustment position from the service manual-

Rear suspension
Spring free length 220.0 mm (8.66 in)
Installed length 211.5 mm (8.33 in)
Spring rate K1 80.00 N/mm (456.80 lb/in) (8.16 kgf/mm)
Spring stroke K1 0.0

Spring preload adjusting positions
Minimum 216.0 mm (8.50 in)
Standard 211.5 mm (8.33 in)
Maximum 206.0 mm (8.11 in)

That makes sense.

Your preloads fine then.

On gasgas bikes (I had one) the guros on the gasgas forum reccomend to set the shock preload to 2-8 mm based on feel and forget about sag, I dont see why that wouldnt work for the wrr too.

Does anyone raise their forks over 18mm on WRR?

I'm getting the dreaded high speed wobble on the interstate.  Running stock tires. (I've read it can contribute to wobble, as well as knobbies, gusts from other traffic, riding in the middle of the lane, etc) If I scoot my butt back, move my head as far forward and close to the windshield as possible, and then put most of my weight on my knees into the shrouds it seems to help.  But I'm thinking perhaps if I raise the front forks (currently at 18mm) up to 25mm or even 32mm (1.25" has been stated as the max) that may put enough weight on the front end to dampen the wobble.

This of course is on an R version.  My thinking is that the X version geometry has 17" wheels on front and rear - the R version is 21 and 18- so dropping the front wheel by 1.5" should be similar to running 17" on front and rear correct?

A steering damper seems like an ideal but overly expensive fix.

Have you tried removing the windshield to see how much its affecting the wobble?

Rushblur wrote:

But I'm thinking perhaps if I raise the front forks (currently at 18mm) up to 25mm or even 32mm (1.25" has been stated as the max) that may put enough weight on the front end to dampen the wobble.

Raising the forks more will make the wobble worse, not better.

That's because when you raise the forks in the triple clamps you are effectively decreasing the caster angle, which makes the bike respond faster to handlebar input, that is, it makes it more twitchy -- which is the opposite of what you are looking to achieve.

What you want is to lower the forks so that the caster angle is increased, making the bike more stable (think of a chopper).

Tyres also play a role in how the front end behaves; what tyres are you using, and at what pressure?

johnkol wrote:

Rushblur wrote:

But I'm thinking perhaps if I raise the front forks (currently at 18mm) up to 25mm or even 32mm (1.25" has been stated as the max) that may put enough weight on the front end to dampen the wobble.

Raising the forks more will make the wobble worse, not better.

That's because when you raise the forks in the triple clamps you are effectively decreasing the caster angle, which makes the bike respond faster to handlebar input, that is, it makes it more twitchy -- which is the opposite of what you are looking to achieve.

What you want is to lower the forks so that the caster angle is increased, making the bike more stable (think of a chopper).

Tyres also play a role in how the front end behaves; what tyres are you using, and at what pressure?

+1 ^^^

johnkol wrote:

Rushblur wrote:

But I'm thinking perhaps if I raise the front forks (currently at 18mm) up to 25mm or even 32mm (1.25" has been stated as the max) that may put enough weight on the front end to dampen the wobble.

Raising the forks more will make the wobble worse, not better.

That's because when you raise the forks in the triple clamps you are effectively decreasing the caster angle, which makes the bike respond faster to handlebar input, that is, it makes it more twitchy -- which is the opposite of what you are looking to achieve.

What you want is to lower the forks so that the caster angle is increased, making the bike more stable (think of a chopper).

Tyres also play a role in how the front end behaves; what tyres are you using, and at what pressure?

Running stock tires with plenty of tread but also 6 years old (po used non-dot knobbies exclusively).  18psi/25psi cold as suggested.  Removed the windshield.  No difference.  

I think you guys are failing to recognize the rear is lowered by 2".  Thus a front lowered by .7" is getting back to something similar to stock geometry.  I'm going to look into bar risers and get the raise the forks up to 1" total and go from there.

Installed 15mm handlebar risers and then raised the forks to 1.25" based on some advice from local guys at advrider.com

High speed wobble solved.

Rushblur wrote:

I think you guys are failing to recognize the rear is lowered by 2".

Lowering the rear means that the caster angle is increased, therefore the bike becomes more stable in a straight line, but more difficult to turn.

The only way I can think of the bike becoming more unstable by lowering the rear, is some weird aerodynamic effect -- maybe the air now catches the front fender and makes it shimmy at certain speeds?

Rushblur wrote:

Installed 15mm handlebar risers and then raised the forks to 1.25" based on some advice from local guys at advrider.com

High speed wobble solved.

It's good that the wobble is solved, but there is something wrong with the solution: the WRR forks do not have a range of 1.25" to be adjusted. The triple clamps need to grip the forks at the bulged areas of the forks, and these areas only allow for a range of slightly less than 1". If you slid the forks 1.25" upwards then your triple clamps are not fully gripping the forks.

I've read that the max to raise front forks is 1.25".

Examples:
http://yamaha-lowering-link.blogspot.com/2008/10/yamaha-lowering-link-question-of-day.html
https://www.youtube.com/all_comments?v=3YpC4pyOSSc
http://www.thumpertalk.com/topic/560111-new-info-on-wr250r-and-x-lowering/#entry5358885

Rushblur wrote:

I've read that the max to raise front forks is 1.25".

Don't take other people's word on this, just take a look at your bike: now that you have raised the fork tubes 1.25", are the triple clamps gripping just the bulged-out parts of the fork, or have they slid beyond these and parts of them are gripping air?

I measured my forks last night, and if I were to slide them 1.25", the triple clamps would be partially gripping air.

johnkol wrote:

Rushblur wrote:

I've read that the max to raise front forks is 1.25".

Don't take other people's word on this, just take a look at your bike: now that you have raised the fork tubes 1.25", are the triple clamps gripping just the bulged-out parts of the fork, or have they slid beyond these and parts of them are gripping air?

I measured my forks last night, and if I were to slide them 1.25", the triple clamps would be partially gripping air.

Thats not the only issue, if the tire can hit the fender when you bottom the suspension out you will crash badly.

You need to keep 10.6 inches plus a touch extra between the top of the tire and the bottom of the fender when the forks are ertended all the way, this is the easiest way to measure the clearance.

I honestly have no idea how close the tire gets to the fender as my bikes stock height and I dont want it lower.

Thanks for sharing two major concerns on raising the forks 1.25" in the front with 2" lowered in the rear.  

Are forks sufficiently attached?
I found that it took some effort to raise the forks from 18mm to ~32mm.  Tried just loosening the bolts, bike on a center lift, and rocking the front of the bike into the ground.   Tubes didn't move at all.  So took off the wheel completely - and even then took alota twisting to get those suckers to move.   I have little concern about the forks not being sufficiently gripped with those four bolts tightened.

Will the forks bottoming out?
As pointed out I weight 140 w/o gear.  The stock front fork springs are too heavy for my weight to start with.  I'll put some plastic ties on the forks but even riding on the mx track with my son last weekend seemed like I still had about 2-3 inches of uncompressed suspension (just by studying the oil/dirt patterns on the bottom of the forks).  If anything I'm unable to achieve enough sag on the front - got the rear sag to just around 4".

I don't know what all is screwed up with your bike thanks to the Yamalink, but when I accidentally set my rear shock on full soft rebound I thought the damn thing was blown until i went back and saw that I had adjusted it wrong.  WAAAAY too soft, and much much much better at full stiff.  I do weigh a lot more than you, but full soft doesn't seem right to me. Get any chattering going over braking bumps or lots of kicking around on washboarded roads?

Also fwiw Highfive's suspension recommendations are based around a somewhat heavier rider (180ish pounds) riding very aggressively mostly off-road. Rocks and jumps normal and expected, etc.

Rushblur wrote:

Will the forks bottoming out?
As pointed out I weight 140 w/o gear.  The stock front fork springs are too heavy for my weight to start with.  I'll put some plastic ties on the forks but even riding on the mx track with my son last weekend seemed like I still had about 2-3 inches of uncompressed suspension (just by studying the oil/dirt patterns on the bottom of the forks).  If anything I'm unable to achieve enough sag on the front - got the rear sag to just around 4".

You should lower the oil height in the forks to 120-130mm from the top, stock is 95ish mm and wont let light guys use all the travel, im quite heavy and still bottomed them out tho lol.
This will give you a much smoother ride for next to no money.

stock oil height is 105mm fwiw

It should be but its more like 95 if you measure what the factory put in the forks, they over filled them making them stiff and harsh for light guys.

Got the bike on a stand. Loosened up the fork caps most of the way but I can't seem to get the suckers to unscrew out. Any ideas?

I found that you need to loose up the top triple clamp a bit to loosen up the fork caps.

Just remember that if you want to set fork oil level and be able to compare to what the standard oil level is, you need to completely fill the fork with oil and bleed the cartridge to get all of the air out, bottom the fork leg without the spring, etc., and then suck out the excess oil, dropping it down to your desired level.
Just opening up the fork and measuring the oil level is not accurate.

Thanks for the tips YZEtc and rsteiger!

I'm the second owner of the bike but it only had 4k miles on it.  It is reasonable to assume the PO didn't alter the fork oil... and its reseasonable to assume the factory put the same amount of oil in each fork... thus if I take the same exact amount of fork oil out of each fork I should be good?  Trying to work smarter here.

Inner tube outer diameter  46mm
Inner tube outer radius    23mm
Stock "Air" Level            105mm
Suggested "Air" Level    125mm

2(pie)r^2
Area of circle       = 1,662 mm
Volume of cylinder = 33,240  cubic mm
                = 33.24 ml

Granted the cylinder is a bit smaller because of the volume of the tube itself.  Ballpark it and aim to remove roughly 30 ml from each fork.