01 YZ250 midvalve question.

bclapham

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#1
OK guys, ive got the showas on my rm working really, really well and i raced the bike on the weekend and it performed great. now i am almost finished getting it dialed, i am bringing the yz250 out of mothballs and the fork really needs attention! (dont know what i am thinking lining a 125 up against 40 dudes on 450f's and 520 ktms :eek:

i bought the bike used, and it had already been resprung and revalved for a guy in my weight region- 220lbs. the midvalve had been left stock and it looked like they had just threw a few bigger LSC shims on the BV and called it a day. hated the fork, it handled big slap downs ok, but was crap everywhere else.

i did a couple of trys with the revalve myself, i went to a much lower lift on the mid and chucked all of the .15 BV shims for a stack made up with .1's but i am still not happy with these forks.

so before i get into them again, i want to check with you guys if my mid valve design is ok since i am more than happy to do a BV shuffle, but dont want to get into taking the cartridge apart every week:(

here is my mid, is it ok and can i tune it from here with the BV or do i need to rethink- not looking for a hand out, just a yes or no if i am going along the right lines:)

27.1
25.1
22.1
20.1
18.1
16.1
14.3 clamp

then ive got a 1.5mm 27mm od washer and a couple of 27.1 shims at the back of the stack to set the lift at 0.5mm

thanks

Bruce
 

JohnScott

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#2
Bruce,

FWIW, I dumped the MV stack on the forks I bought from you. I'm only riding harescrambles now and need a lot more plushness. I've gone to a check plate on the MV and am experimenting with a little beefier stack (than your experimental stack) on the base valve using the stock piston. I am also playing with different stacks on my RT GVs in my other forks. I'm sure that there is something to be gained with a good MV stack but it's just too time consuming at my level of knowledge to take the cartridge apart whenever I want to make a chage. By just playing with the BV, I can just flip the bike upside down and change the stack in a matter of minutes.

John
 

bclapham

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#3
thanks John. i think i will stick with the same MV stacck and go back to a larger lift, about 1mm- it seems this low lift mid valve we are constantly being told is the way to go is all good and well if you can get the base valve soft enough, but i havent managed to do that. if i go softer/more lift on the mid then i can tune much easier with the BV. i am really happy with my showa rm forks now i just hope i can get these kyb somewhere near them.
 

JohnScott

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#4
If your trying to get the BV stack softer, I have an extra set of KYB base valve bodies (pistons) I can get to you cheap. You could try to drill them out to get more flow. Of course, it would be difficult to replicate or measure your alterations unless you have a real accurate way of drilling - plus there's no going back if you don't like the results...

But in the end, playing with the lift on the MV might be easier but I HATE taking that dang cartridge out every time I want to make a small adjustment.

BTW, you were talking about selling that YZ a couple of months ago...?