USD preload adjustment

[sliabhrossa]

Hello all,
Im new on here but am delighted to be a member.
Im riding an XR650R supermoto.
Mikuni pumper carb, Full Akrapovic race exhaust, 15L tank, 200W stator, new loom , custom battery box, custom dash, ktm headlight an fender, black paintjob etc etc...

My question:
She has yolkes and USD forks from a 2002 crf 450, they were correctly fitted, however, she tends to be flighty on the front over 100kmph or slower when accelerating hard, we've tried everything... the rear sag, the rear linkage was worn an replaced, wheels balanced, forks dropped in the yolkes, new oil, heavier oil, new headrest bearings, played around with compression an rebound, to no avail.

My buddy reckons its preload. Im inclined to agree at this stage as they are off a much lighter bike.
Anyone know how to increase the preload on these 2002 CRF450 USD's?
Would it help?

Comments and opinions greatly appreciated, rossa

[catteeclan]

Welcome.

Can't help with the folk prob but would love to see some pics.

[Daz Max]

You don't say if you've changed the spring rates.
This was mentioned in here- XR Up Side Down Suspension

Crosser set ups are useless on a 'Moto.Try some stiffer springs.

[great escape]

hi rossa, we met a while back in july, i was on the xr650 and my friend on the triumph. i have already described and sung the praises of your bike in this forum!! hope fully i will see yourself and kieren next time im over. back to te fork issue, what about a steering damper?, also what tyre pressures are you running?, maxxis recomend 26 psi for the xr, the supermoto tyres being a specific construction. regards, steve aka great escape

[sliabhrossa]

Hi Steve, great to hear from you man, hope the trip went well, thanks for the compliments too, ill have to post some pictures now...

Yea i dont think its tyre pressure, ill either have to work out a way of increasing preload or if i cant then fit harder springs, just got to find the time to rip into them.

Cheers rossa