SuzukiSavage.com - Fork oil change

piedmontbuckeye

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Fork oil change
06/12/17 at 08:05:23

Over the weekend, I did my fork oil change. Mine had 9,000 miles on it, and one never knows how the previous owner really kept up. I typically try to replace all liquids and lubricants when purchasing a used anything!

I am glad I did. I removed one fork at a time, and drained out old oil. Wow, was it dirty - had the look of grayishness from normal wear. I rinsed each out with kerosene and did so at least three times before kero ran clean. Then I used Marvel Mystery oil to re-lube and did so 2x on each fork then completely drained out for some time. Then I added the prescribed amount of 15w BelRay fork oil - up to 2.95" from top of fork when compressed with no spring inserted.

My one question is. What weight oil do most of you use? I used 15w (from previous experience on other road bikes, and that is what someone on here recommended). However the forks seem a little too stiff now. Does any of you run 10w instead?

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Gary_in_NJ

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Re: Fork oil change
Reply #1 - 06/12/17 at 08:57:09

Sounds like you did it perfectly. 15w is correct. A few things to consider:

- You don't know what weight was in there previously
- You don't know if they were filled correctly previously
- There are no standards with fork oil. 15w from one manufacturer is not the same as 15w from another.

Before declaring the forks as too stiff, ride it for a while and determine if you like the total/complete motion; ride comfort, compression and rebound. You may gain more from adding/removing some oil then a full fluid change.

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28886 L.A. California Gender:	Re: Fork oil change Reply #2 - 06/12/17 at 09:27:29 mmm kerosene... wish I thought of that. 15w is what I used, seems pretty soft for my 250# bulk.
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Fork oil change Reply #3 - 06/12/17 at 23:01:12 My 160ish pounds can bottom the forks all too easily.
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Dave

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Re: Fork oil change
Reply #4 - 06/13/17 at 04:25:00

justin_o_guy2 wrote on 06/12/17 at 23:01:12:

My 160ish pounds can bottom the forks all too easily.

There is no reason to keep riding that way - it is easy to fix. Add a small amount of fork oil to each tube.....keep doing that until the bottoming out issue is resolved. If you reduce the amount of air at the top of each fork leg, it stiffens the resistance as the fork gets in the lower 1/3rd of the fork travel. It is best to measure the level of the oil with each fork tube compressed and the spring removed.

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Gary_in_NJ

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Re: Fork oil change
Reply #5 - 06/13/17 at 04:57:01

Adding oil solves one problem, but creates another. We need an air chamber in the forks so the moving oil has space, otherwise the forks become hydrolocked. With an air gap of 75mm, the oil height is already VERY high in Savage to overcompensate for the poor damping and the long rake.

If you want to experiment with an oil height change I suggest doing it in increments of 10mm, and then once you get "in the zone" add/remove as required for fine tuning. Each 8.55ml (0.289oz) of oil added or removed equates to a 10mm change in oil height.

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piedmontbuckeye

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Re: Fork oil change
Reply #6 - 06/13/17 at 05:51:17

Dave wrote on 06/13/17 at 04:25:00:

justin_o_guy2 wrote on 06/12/17 at 23:01:12:

My 160ish pounds can bottom the forks all too easily.

There is no reason to keep riding that way - it is easy to fix. Add a small amount of fork oil to each tube.....keep doing that until the bottoming out issue is resolved. If you reduce the amount of air at the top of each fork leg, it stiffens the resistance as the fork gets in the lower 1/3rd of the fork travel. It is best to measure the level of the oil with each fork tube compressed and the spring removed.

I would think that the way would be to go to either thicker/thinner oil to achieve the right dampening?

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piedmontbuckeye

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Re: Fork oil change
Reply #7 - 06/13/17 at 05:57:08

verslagen1 wrote on 06/12/17 at 09:27:29:

mmm kerosene... wish I thought of that.

15w is what I used, seems pretty soft for my 250# bulk.

"mmm kerosene... wish I thought of that." - are you mocking me or do you really mean this? For me, I have used white (clear) kerosene to wash lots of things, and it did work (for me anyway) well for these forks. I was also very careful to be sure to thoroughly drain them before I moved on to the Marvel Mystery oil part.

I used to weigh more, but am now down to about 185# - so by my losing weight, the rides seem more "stiff" to me. I am sticking with the 15w because I don't want to spend more $$ on 10w and then take the time to change it.

On my dirt bikes, I used a combination of 10w and 5w to achieve about 7.5w. On street bikes I have used 15w pretty regularly.

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Dave

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Re: Fork oil change
Reply #8 - 06/13/17 at 06:15:57

piedmontbuckeye wrote on 06/13/17 at 05:51:17:

I would think that the way would be to go to either thicker/thinner oil to achieve the right dampening?

The weight of the oil is chosen so that the forks can follow the bumps and irregularities in the pavement and provide a smooth ride...a ride that is not choppy if the oil is too thick or bouncy if the oil is too thin. - the weight of the fork oil should not be altered to fork travel. The stiffness of the bottom 1/3rd of the fork travel can be adjusted and limited by the amount of air space in the forks. Start by confirming your forks have the proper weight and amount of oil in them...then add a measured amount of oil in each fork if you need a bit more stiffness in the forks as the suspension approaches the bottom of the travel. As Gary said you don't want to get too little air - but a 160 lb JOG should not be bottoming the forks.

Read the comments about the Oil Level in this article:

http://www.strappe.com/suspension.html

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Gary_in_NJ

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Re: Fork oil change
Reply #9 - 06/13/17 at 06:24:32

justin_o_guy2 wrote on 06/12/17 at 23:01:12:
My 160ish pounds can bottom the forks all too easily.

Bottoming forks is a dangerous condition. You could easily lose control. It's also an indication of a potential problem within the forks themselves such as:

- Broken spring
- Cracked damping rod
- Blown fork seals resulting in loss of oil

Get this resolved before you crash-test your leathers.

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piedmontbuckeye Senior Member Offline Go Bucks! Posts: 496 Easley, SC Gender:	Re: Fork oil change Reply #10 - 06/13/17 at 06:33:23 I have noticed that these forks do not have a lot of travel compared to others!
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justin_o_guy2

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Re: Fork oil change
Reply #11 - 06/13/17 at 08:21:19

Gary_in_NJ wrote on 06/13/17 at 06:24:32:

justin_o_guy2 wrote on 06/12/17 at 23:01:12:
My 160ish pounds can bottom the forks all too easily.

Bottoming forks is a dangerous condition. You could easily lose control. It's also an indication of a potential problem within the forks themselves such as:

- Broken spring
- Cracked damping rod
- Blown fork seals resulting in loss of oil

Get this resolved before you crash-test your leathers.

I just accepted it as a penalty for going too fast on crappy roads. I have been hit in the butt hard enough to pop my back a few times.. The rear bottoms too..
I'm learning the roads though, and the whoopings are decreasing. The bike has eight thousand miles on it and I'm sure she didn't hit anything to damage the thing.. I really don't want to go digging in forks. It's running through turns at almost fifty that a car would be starting to squeal tires at around 45. And rock solid doing it. When the suspension gets bottomed, I'm not just sitting there. I'm taking a beating. I totally don't like it, but bad spots exist and the roads are too inviting to Not play. I'm getting better at seeing them coming.

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Gary_in_NJ

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Re: Fork oil change
Reply #12 - 06/13/17 at 08:40:03

If the roads are that crappy, I bet you blew your fork seals a long time ago and you are riding on the springs. It might be worth removing the forks (one at a time), get the fork vertical, remove the spring (slowly so the oil stays in the fork), compress the slider and then measure the air gap. If it's more than 3" you've lost oil and have blown seals.

A well functioning suspension sure would be welcome on crappy roads.

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piedmontbuckeye

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Re: Fork oil change
Reply #13 - 06/13/17 at 13:29:48

Gary_in_NJ wrote on 06/13/17 at 08:40:03:

If the roads are that crappy, I bet you blew your fork seals a long time ago and you are riding on the springs. It might be worth removing the forks (one at a time), get the fork vertical, remove the spring (slowly so the oil stays in the fork), compress the slider and then measure the air gap. If it's more than 3" you've lost oil and have blown seals.

A well functioning suspension sure would be welcome on crappy roads.

**************

It would seem to me that what you are suggesting (blown seals, no oil left) would result in "boing boing boing" rather than forks bottoming out (which could happen also). Riding on just springs wouldn't bottom out unless the hydraulic process also works on the compression side of the action (which some do).

It sounds to me like his step should be to either get springs with more tension or put more preload on springs.

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gizzo

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Re: Fork oil change
Reply #14 - 06/13/17 at 16:20:33

that's what I was thinking, too. would be better to respring the fork to suit rider weight than fudge about trying to fix the problem with oil. the stock springs would have to be a compromise Suzuki chose to have a fork that worked ok for everyone. Sometimes it's worth tuning the fork so it works brilliantly for yourself. it's not really cheap, but worth it if you like handling. or your bike bottoms out all the time. that's no fun.

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