Midvalve on yzf 250

thomasw · Jan 5, 2003

I dont like the setup on stock midvalve yzf 250 -02, it looks like a checkplate whit about 1.5mm lift. I want it wiht 0.7 lift and an other valving, how do i do that???

I thinking of a schimstack something like this:

Midvalve

Outer diam: Thickness:

27 10
27 10
27 10
27 10
25 10
22 10
20 10
18 10
16 10
13 25
14 30
14 30
15 40
20 40

Is this something to start wiht or is that to hard.

//Thomas

thomasw · Jan 6, 2003

somebody!!!!!!!!!

gbs1 · Jan 6, 2003

Sounds pretty firm try 27,27,27,25,22,20 16,14x30x(2),15x40,x20x40

this works decently depending on your ability and what type of ride you are looking for, you never said what you did not like about the MV set up.

thomasw · Jan 6, 2003

I drive only mx,and iam not so fast.
Standard mid valve have to much float, lift 1.5 mm, have heard that schims will be bend.

Standardfork seems to be hard in brakingbumps and stutters, i think it rides to far down in travel. I weight 181 ibs and have standard spring in fork and shock

gbs1 · Jan 6, 2003

Try this remove the 16x.10 off the piston face leave the .50 plate removing the 16x.1 will elimate the bleed and help hold up the bike. Then try
27x1x(3),25x1,22x1,20x.1,16x1,14x.30(2),15x.40, 20x.40.

this should provide a decent baseline for you to test from. Are you changing the base valve too?

thomasw · Jan 6, 2003

Originally posted by gbs1
Try this remove the 16x.10 off the piston face leave the .50 plate removing the 16x.1 will elimate the bleed and help hold up the bike. Then try
27x1x(3),25x1,22x1,20x.1,16x1,14x.30(2),15x.40, 20x.40.

this should provide a decent baseline for you to test from. Are you changing the base valve too?

What do you think of 0.7 lift,can that make the forks to harsch.

Standard basevalve:
24 15
24 15
24 15
24 15
22 15
20 15
18 15
16 15
13 15
11 25

I think that is to stiff for me

My basevalve:
24 15
24 15
24 15
22 15
20 15
18 15
16 15
14 15
12 15
11 25

What do you think of it?

Sorry if my english is not so good.I am from sweden and whery bad in language

gbs1 · Jan 6, 2003

your first shim stack will be to stiff for what you are look for. I don't like running all those .15's in the base valve I gennerally change a large portion of them to .10's depending on what the rider needs, weight and skill level. But your stack will be plusher than stock. You will notice some difference thorogh out.

thomasw · Jan 6, 2003

Originally posted by gbs1
your first shim stack will be to stiff for what you are look for. I don't like running all those .15's in the base valve I gennerally change a large portion of them to .10's depending on what the rider needs, weight and skill level. But your stack will be plusher than stock. You will notice some difference thorogh out.

Exactly what i have thinking about, this is the first bike i have with only 0.15 schims.

I have an other basevalve stack:

1 24 10
2 24 10
3 24 10
4 24 10
5 24 10
6 24 10
7 24 10
8 24 10
9 24 10
10 23 10
11 22 10
12 20 10
13 18 10
14 16 10
15 13 10
16 11 25

Maybe this have to littel hsc, i think i no when i test it.

What do you think of 0.7 lift or float i dont no the name you use??

KTM-Lew · Jan 6, 2003

Does your bike have progressive springs?

If so you probably need to change springs.....the progressive's are tough to get the bike to stay up in the stroke.

The bikes imported to the US have straight-rate springs, so you need to take this in account. You are on the heavy side for the stock set-up regardless of which springs you have. I would start with the correct springs first. :think:

Jeremy Wilkey · Jan 6, 2003

Originally posted by gbs1
Try this remove the 16x.10 off the piston face leave the .50 plate removing the 16x.1 will elimate the bleed and help hold up the bike.

Gary can you exsplain to me how this is gonna hold the bike up? Anyway I just had to know where you where coming up with this one.
BR,
Jer

thomasw · Jan 7, 2003

Originally posted by KTM-Lew
Does your bike have progressive springs?

If so you probably need to change springs.....the progressive's are tough to get the bike to stay up in the stroke.

The bikes imported to the US have straight-rate springs, so you need to take this in account. You are on the heavy side for the stock set-up regardless of which springs you have. I would start with the correct springs first. :think:

What springs do you think i need?? Is it progressive springs in europe??

marcusgunby · Jan 7, 2003

yes as far as i know the euro bikes have pregressives.

thomasw · Jan 7, 2003

Originally posted by marcusgunby
yes as far as i know the euro bikes have pregressives.

What do you think should i mess with the midvalve or change springs.

marcusgunby · Jan 7, 2003

I dont like progressives-like KTM lew said you need to start with the correct springs for your weight-then go on from there if it doesnt work well.

thomasw · Jan 7, 2003

Originally posted by marcusgunby
I dont like progressives-like KTM lew said you need to start with the correct springs for your weight-then go on from there if it doesnt work well.

how hard springs for my weight front and shock???

marcusgunby · Jan 7, 2003

try www.mx-tech.com and www.racetech.com and goto spring rate generator-put in your weight and it will give you the spring rates required.

thomasw · Jan 8, 2003

Originally posted by marcusgunby
try www.mx-tech.com and www.racetech.com and goto spring rate generator-put in your weight and it will give you the spring rates required.

Stock springs is front 0.43 schock 4.9, mx-techs site says i shoud have front 0.43 and shock 4.8.

Thanks for all replys

//Thomas

marcusgunby · Jan 8, 2003

thomas you need to compare with the rates in your manual as those rates on the sites are the US ones-the generator has produces the correct springs for your weight but not the right std springs.

DEANSFASTWAY · Jan 9, 2003

You know, I have a real fastrider who is real light but hes a real jumper, He likes the bike 03 250f but thinks its a bit harsh ,maybe I should lookinto some euro springs for him . wonder what the rates are and or what the progression rate looks like . Anybody know ??

marcusgunby · Jan 9, 2003

The yZ progressives are better than the old KX ones-the YZs are only slightly progressive-something like 0.42 -0.44 but dont quote me on it.

Midvalve on yzf 250

thomasw

thomasw

gbs1

thomasw

gbs1

thomasw

gbs1

thomasw

KTM-Lew

Jeremy Wilkey

Owner, MX-Tech

thomasw

marcusgunby

thomasw

marcusgunby

thomasw

marcusgunby

thomasw

marcusgunby

DEANSFASTWAY

marcusgunby

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Midvalve on yzf 250

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