Lowering fork oil

maxamillion 125
Edited Date/Time 4/24/2015 8:01am
Hey guys, I have a 14' yz250f and weigh 160lbs with gear, 30B class. I"m a little light for the 4.7 N/mm springs. Can dropping the fork oil by 20cc help? Also I've noticed I get head shake on one part of the track pretty often. Could that be because the forks are to high in the stroke? Thanks
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mxtech1
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mxtech1 4/17/2015 8:07am
4/17/2015 8:07am
during what conditions does the bike feel stiff?

first thing I would try to reduce headshake is to tighten the steering stem nut
maxamillion 125 4/17/2015 10:03am
4/17/2015 10:03am
mxtech1 wrote:
during what conditions does the bike feel stiff?

first thing I would try to reduce headshake is to tighten the steering stem nut
It feels kinda harsh in the chop and breaking bumps.
maxamillion 125 4/17/2015 10:04am
4/17/2015 10:04am
On my tracks biggest jump I still have about 1-1.5" of travel left. I've never bottomed it out.
mxtech1
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mxtech1 4/17/2015 1:04pm
4/17/2015 1:04pm
Can you tell us how many clicks in or out you are on the comp and rebound settings?

What's your shock sag set at?

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maxamillion 125 4/17/2015 2:41pm
4/17/2015 2:41pm
Sag is 103mm. 12 clicks out on compression, 10 on rebound.
Kartwheel
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Kartwheel 4/20/2015 1:57pm
4/20/2015 1:57pm Edited Date/Time 4/20/2015 1:59pm
Make sure your forks are not bound up on the axle, if they are they will be sticky and not absorb bumps when the front is light under acceleration and wiggle side to side. Bleed the air out between motos as well
The springs are a bit stiff front and back as well
CarlinoJoeVideo
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CarlinoJoeVideo 4/20/2015 3:21pm
4/20/2015 3:21pm
Maybe try a little more sag 105-106mm to help with the headshake.

Also where are your forks sitting in the triple clamps?

Removing oil will make the first part of your forks stroke feel softer.
maxamillion 125 4/20/2015 6:52pm
4/20/2015 6:52pm
I bleed the forks every time I ride and the forks are in the stock position in the triple clamps. How much oil should I remove?
mxtech1
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mxtech1 4/21/2015 7:20am
4/21/2015 7:20am
Removing oil won't fix the stiff feeling in chop or breaking bumps. The forks are probably only using less than 1/2 their stroke over these obstacles.

I think you need to go softer on the compression. Start with 2 clicks at a time, I wouldn't be surprised if you end up near 18 clicks out. You may need to adjust the rebound, but work on compression first.

slipdog
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slipdog 4/21/2015 7:47am
4/21/2015 7:47am
You spelled KTM 250f wrong.

4cs forks are horrible and the only fix is to replace them. KYB "SSS" are the pinnacle of performance and you could race at the national level with them bone stock... /end sarcasm

Lowering the oil level will help, but only a small amount. You need softer springs for that bike. You said 160 in gear so, 140ish without gear? .44/ 5.2kg
maxamillion 125 4/24/2015 6:33am
4/24/2015 6:33am
mxtech1 wrote:
Removing oil won't fix the stiff feeling in chop or breaking bumps. The forks are probably only using less than 1/2 their stroke over these obstacles...
Removing oil won't fix the stiff feeling in chop or breaking bumps. The forks are probably only using less than 1/2 their stroke over these obstacles.

I think you need to go softer on the compression. Start with 2 clicks at a time, I wouldn't be surprised if you end up near 18 clicks out. You may need to adjust the rebound, but work on compression first.

Alright, I'm going out more clicks on compression and see if that helps. If not I'm dropping the oil 20cc. Is head shake caused by to far out on compression?
mxtech1
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mxtech1 4/24/2015 8:01am
4/24/2015 8:01am
20cc of oil removal is drastic. I would not exceed 5cc at a time.

For the head shake, need to know if it happens while you are on the gas or on the brakes?

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