Removing small amount of fork oil

7008 Views 24 Replies 8 Participants Last post by Tearaway, Aug 22, 2017

Tearaway

Discussion Starter · May 13, 2017

Is it possible to remove a small amount of fork oil with the forks in place? My rebound is too slow even with it all dialed out. I believe if I take a little oil out that it will help a little which is really all I need

I don't want to go through the hassle of stripping the forks down and doing an oil change which is probably what I should do.

Is there a handy way of doing it by popping the caps and any idea how much I should take out?

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skidooboy

· #2 · May 13, 2017

if your rebound is too slow, the amount of change you are trying to get, is not enough to get, by removing oil. the forks need servicing, and more rebound shims added in the shim stack. read: re-valve. you want your adjusters to have room to move, on either side, so you can make adjustments. having them maxed out, then trying a Band-Aid, is not a solution to the problem.

it doesn't take that much to remove the forks for service. just bite the bullet and do it right so, you don't cause more or different issues, later. Ski

Reactions: 2

Tearaway

Discussion Starter · #3 · May 13, 2017

Thanks Ski,

I know you're right... but I don't have the time nor finances to stick into this bike at the moment ( if my misses sees me heading for the garage one more time it'll be divorce :2bitchslap: )so I want to try a quick fix first and then if that doesn't work I'll bite the bullet. The improvement I'm looking for is minor!

rcannon

· #4 · May 13, 2017

I dont see how you will accomplish a rebound change with oil level. Heres a good article talking about oil height, and what it does.

Keep in mind, hes talking dirt bike forks with 12 inches of travel..but the idea is the same.

Motocross Action Magazine HOW TO FIX YOUR FORKS WITH FORK OIL HEIGHT TRICKS | Motocross Action Magazine

Tearaway

Discussion Starter · #5 · May 13, 2017

rcannon said:
I dont see how you will accomplish a rebound change with oil level. Heres a good article talking about oil height, and what it does.

Keep in mind, hes talking dirt bike forks with 12 inches of travel..but the idea is the same.

Motocross Action Magazine HOW TO FIX YOUR FORKS WITH FORK OIL HEIGHT TRICKS | Motocross Action Magazine

You could very well be right. According to the article it will just let the oil move more.

Would an oil change to a lighter oil do the job? I'm only after a small improvement!

chiffeee

· #6 · May 13, 2017

the way to do it on the bike is, to open the cap on top and using a measuring tool and a tool that looks like a syringe to add/deduct oil.

but these guys are right .by taking oil away not going to make any difference and could make the forks not functioning correctly . adding oil makes the difference from stock level. making the compression and rebound slower . but if you go lower then standard level for that fork (usually 122mm) then can make the fork create air bobble and not functioning correct.

By changing the oil weight can make what you need to achieve, but keep in mind the stock oil usually is low on its weight and you may not find lower weight , usually what i have seen people go to a higher weight and lower air gap to make the forks stiffer/ slower on rebound and compression.

only way to do it correctly is to re valve the forks.

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Bottoms-Up

· #7 · May 13, 2017

Tearaway said:
if my misses sees me heading for the garage one more time it'll be divorce

This sounds like a bigger issue then slow rebound. :surprise:

Reactions: 2

skidooboy

· #8 · May 13, 2017

thicker oil would help, less oil will hurt. you need to get the mrs interested in riding herself, then you dont have "those issues"... but, then everything you do with bikes, toys costs double. don't ask me how I know.

Ski

rcannon

· #9 · May 13, 2017

If you have rebound that is "too slow", a lighter oil is what you are looking for.

A thicker oil will have a more difficult time traveling through the valving, and slow rebound.

Im not sure what specific fork oil we are supposed to have. If its showa ss7, and it may be, that looks like its a 5w.

This chart works really well as it lists so many of the fluids we have access to. You can see, also , that someones 5w may be different than others 5w. They break the fluids down and measure in cSt centiStokes. Suspension Fluid - Pvdwiki

Just a fancy name for soemthing more accurate than 5w, 10w, etc. The lower the number, the thinner the fluid is.

From the list, the redline (like water, clear) fluid is probably the easiest to get. My local shop sells it.

Lets say you dumped out the stock oil, then switched to this redline, it should lighten the rebound. I say SHOULD because as chiffeee said, the stock oil is like water, anyway.

The bad part about messing with oil weight is it also messes with compression damping. It will make that lighter, as well.

As a compromise, I think I might try this.

Wanting to decrease rebound makes me think the fork is harsh. Hits a bump and does not ready itsle , fast enough, for the next bump.The stock Kawasaki forks get pretty harsh, halfway through their travel.

How about increasing preload, a few turns. Bring the fork back up to a position where its not running into the middle of its travel so easily.

At that point, the bike may be too tall. Bring the fork up through the top triple clamp 5mm so the front end stays about where it was.

The cartridge forks are a pita to deal with, in regards to oil. Unless you get 100% of the oil oil out, you'll end up with some odd mixture of stock and aftermarket fluid. Even if it were amazing, you would never be able to duplicate it again if you blew a seal, or needed fork service.

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skidooboy

· #10 · May 14, 2017

my bad, I read the original post wrong, I thought he did not have enough rebound dampening, and was looking to slow the rebound down more. (the gen4 rear shock is like that, not enough rebound dampening in the shock adjustment).

thinner oil would help but, still be a band aid. Ski

Reactions: 1

rcannon

· #11 · May 14, 2017

skidooboy said:
my bad, I read the original post wrong, I thought he did not have enough rebound dampening, and was looking to slow the rebound down more. (the gen4 rear shock is like that, not enough rebound dampening in the shock adjustment).

thinner oil would help but, still be a band aid. Ski

If you thought your mistake was bad, you should have seen my post helping him set the bike up for his wife. No idea why, but i thought thats what he was doing.

The stock fork settings, and shock settings are tough to deal with. Its not kawasakis fault. How do you set up a fork , or shock, for a rider between 145lbs and 250 lbs who may or may not go to the track.

Same rider may also carry a 165lb passenger, or not....the answer is, you really cant.

Notice one thing on the 10rr, sp2, and bikes in this class with up-rated suspension. Step 1 is to eliminate the passenger seat.

Thsi helps , somewhat, and that passenger weight is no longer accounted for.

Tearaway

Discussion Starter · #12 · May 14, 2017

Thanks for all the input... i suspect it's a revalve ultimately.

Reactions: 1

rcannon

· #13 · May 16, 2017

A revalve, with correct spring will spoil you. You'll never ride a stock fork again and enjoy it.

Highly recommended, but it gets expensive.

evallarta1

· #14 · May 16, 2017

Tearaway said:
Is it possible to remove a small amount of fork oil with the forks in place? My rebound is too slow even with it all dialed out. I believe if I take a little oil out that it will help a little which is really all I need

I don't want to go through the hassle of stripping the forks down and doing an oil change which is probably what I should do.

Is there a handy way of doing it by popping the caps and any idea how much I should take out?

Everyone has hit the nail on the head, airgap affects spring, not damping.

But the bigger question is WHY do you think you have too much rebound? What year bike? There are other variables that you could be missing. What other modifications have you done to the fork, if any?

rcannon

· #15 · May 17, 2017

I would be curious as to his answer, as well.

If you are trying to fix someones suspension, its a dream come true when they are able to nail down such a specific complaint.

You usually get, "Well, i'm not sure..its soft, in a hard sort of way..." and that is a nightmare.

evallarta1

· #16 · May 17, 2017

rcannon said:
I would be curious as to his answer, as well.

If you are trying to fix someones suspension, its a dream come true when they are able to nail down such a specific complaint.

You usually get, "Well, i'm not sure..its soft, in a hard sort of way..." and that is a nightmare.

This is true. That's why asking the right questions gets you the answers you need. But if you think club/trackday riders are bad, try workin with pro riders. They're worse! It's always the bike's fault.

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Tearaway

Discussion Starter · #17 · May 18, 2017

Thanks for all the input.... to answer your questions... I'm trying to set up the bike to my liking. I upgraded the rear spring for my weight 12.5 stone and I'm in the process of correcting the suspension setting for the shock - At present I have don't have enough rebound on the rear but I've made a few adjustments and I'm back on track at the weekend so I'll know then. Tyre wear is pretty obvious it's too fast on the rebound on the rear.

The front is too stiff for my weight and tyre wear on the front has all the hall marks of a rebound issue- with debris on leading edge and wear on rear of the sipe which indicates too slow rebound. Logic tells me to sort out the back first which I am so at the moment I'm just gather info on what to do with the front.

I don't have spare cash to throw into this bike a the moment!

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evallarta1

· #18 · May 18, 2017

Tearaway said:
Thanks for all the input.... to answer your questions... I'm trying to set up the bike to my liking. I upgraded the rear spring for my weight 12.5 stone and I'm in the process of correcting the suspension setting for the shock - At present I have don't have enough rebound on the rear but I've made a few adjustments and I'm back on track at the weekend so I'll know then. Tyre wear is pretty obvious it's too fast on the rebound on the rear.

The front is too stiff for my weight and tyre wear on the front has all the hall marks of a rebound issue- with debris on leading edge and wear on rear of the sipe which indicates too slow rebound. Logic tells me to sort out the back first which I am so at the moment I'm just gather info on what to do with the front.

I don't have spare cash to throw into this bike a the moment!

Be careful with "tire reading". I know it's all the fad right now but you can spend a lifetime chasing your tail trying to get the "perfect" tire wear. A bigger question is what do you FEEL. What are you feeling on track that would suggest that the front springs are too stiff? Also what kind of preload are you running and what gen 10 are you on?

Reactions: 1

Tearaway

Discussion Starter · #19 · May 18, 2017

It's a gen 3 bike. I've dialed all the rebound and compression out. The bike needs a bit of force to turn.

I replaced the rear spring. It was slightly shorter than the standard one but I have good sag of 31mm. Front sag is 36mm.

The other option I'm looking at is dropping the fork tubes in case the slightly shorter spring has altered the ride height.

LDH

· #20 · May 18, 2017

evallarta1 said:
Be careful with "tire reading". I know it's all the fad right now but you can spend a lifetime chasing your tail trying to get the "perfect" tire wear. A bigger question is what do you FEEL. What are you feeling on track that would suggest that the front springs are too stiff? Also what kind of preload are you running and what gen 10 are you on?

100% AGREE & the real truth is most trackday riders suffer from incorrect tire pressure issues long before the actual suspension damping comes into play or even aggregate in the track surface. They don't know their tire gauge is out of calibration or haven't bothered to test different pressures on their own and just rely on what pressure some tire guy or racer once told them to run and those numbers change all the time with DOT race tires based on a myriad of variables and track conditions.

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