fork oil

[Anonymous]

i am changing my fork oil because my forks are spongy. should i bring the fork weight up? to make them alittle stiffer. becuase even back when they were new they were not the best performing shocks

[Hap Call]

Re: fork oil

i am changing my fork oil because my forks are spongy. should i bring the fork weight up? to make them alittle stiffer. becuase even back when they were new they were not the best performing shocks

I did and it made a world of difference for the better.

hap

[Anonymous]

Fork oil Weight

I did mine on a 80GS850 this spring with straight 10WT fork oil. It is too hard for me so I'm going to try 50/50 ATF and see how I like that. Bob

[Billy Ricks]

Just changing the oil alone will make a big difference. Since you've probably got bushings that have worn 15 weight will slow the spring action down some. I'd see how much sag I've got too. That's the difference between the fork fully extended with the front wheel off the ground, then sitting on the ground with your weight in the seat. Measure how much of the upper tube is showing below the triple clamp. The difference in the two measurements is how much sag you have.

Depending on how you ride you can shoot for 1"-1 1/4" of sag for a firm, sporty ride good for hard backroad riding. Go with about 1 1/2"-1 3/4" of sag for a softer ride. Add pieces of PVC pipe with close to the same outer diameter as the inner diameter of the fork tube. How long will depend on how much sag you had. Use a fender washer on top of the fork spring and your piece of pvc on top of that, under the fork cap. Using the spring preload in the back try to get the rear set up close to the front as far as sag.

You don't want to overdamp. Too heavy of an oil or too much damping will not let the spring react as quickly as it should to soak up the road. What you want is controlled spring action. As long as the suspension settles down quickly and is ready for the next bump and doesn't pogo after the suspension is upset the damping is good. Pogoing means you're underdamped. But you still want to have the spring do its quickly so you don't want to overdamp. Get the sag set up first, then decide what needs to be done damping-wise. Go easy after suspension changes and get used to how the bike behaves.

[Anonymous]

About this sag thing?

I measured the amount of sag I have in my front forks. With the forks extended all the way = front tire off the ground. Then with the bike off the stands. I got a little more than 2" of dif. Did I do it right? If so should I do the pvc thing till I get it right? Or would going with a little more air preasure help. Thanks Chris.

[Billy Ricks]

Air pressure will do fine. You can also run with zero air and adjust with spacers.

[daveo]

I've got a good pair of Progressive springs for a 750 if anyone wants them, $35

[Billy Ricks]

Dave's springs will probably work in quite a few models just by playing with the length of the spacers.

[mdole]

Just changing the oil alone will make a big difference. Since you've probably got bushings that have worn 15 weight will slow the spring action down some. I'd see how much sag I've got too. That's the difference between the fork fully extended with the front wheel off the ground, then sitting on the ground with your weight in the seat. Measure how much of the upper tube is showing below the triple clamp. The difference in the two measurements is how much sag you have.

Depending on how you ride you can shoot for 1"-1 1/4" of sag for a firm, sporty ride good for hard backroad riding. Go with about 1 1/2"-1 3/4" of sag for a softer ride. Add pieces of PVC pipe with close to the same outer diameter as the inner diameter of the fork tube. How long will depend on how much sag you had. Use a fender washer on top of the fork spring and your piece of pvc on top of that, under the fork cap. Using the spring preload in the back try to get the rear set up close to the front as far as sag.

You don't want to overdamp. Too heavy of an oil or to much damping will not let the spring react as quickly as it should to soak up the road. What you want is controlled spring action. As long as the suspension settles down quickly and is ready for the next bump and doesn't pogo after the suspension is upset the damping is good. Pogoing means you're underdamped. But you still want to have the spring do its quickly so you don't want to overdamp. Get the sag set up first, then decide what needs to be done damping-wise. Go easy after suspension changes and get used to how the bike behaves.

I've also used 1/4" thick nylon spaces that I can get a True Value or Ace hardware stores. They work pretty good as you can adjust the initial preload to where you think it should be then try a 1/4" either way to see what the difference is. If you stack several of these in each fork tube you can make them easier to handle by putting them together with a screw down the center and fastening them together. I think I used a 1/4 - 20 screw with an aviation lock nut (nylon locking insert on nut) on mine.

Mike

[Anonymous]

Now at 18 psi.

Now at 18 psi, and I have 1 1/2" of sag while I'm on the bike. I forgot to mention that Im using ATF fluid. I have been thinking of going with 10 or 15 fork oil. I would like to stay at 1 1/2, but I also want to have the propor preasure in the forks. Any tips? Thanks Chris.

[Billy Ricks]

Chris,

You might want to think about using spacers and air. 18 lbs is a lot for the seals to have to deal with when the fork compresses. I'm not sure about you bike but when mine was bone stock Suzuki called for less than 3 lbs of air for solo riding. Try 3/4" or so of spacer then check to see how much air it takes to get the sag right.

[Anonymous]

I've found that the easiest way to check fork sag is:
1. Put the bike on the center stand and get the forks fully extended.
2. Put a tie wrap on the fork right at the dust seal.
3. Take the bike off the stand and sit on it.
4. Put the bike back on the stand, get the forks fully extended, and measure between the tie wrap and the dust boot.

[Anonymous]

Manual calls for 11 or 12 psi.

My factory manual calls for 11 or 12 psi. Is the ATF fluid good for my forks to be responsive. I don't want them to be too slow. I think I will go with the spacers till I get the preasure back down to 12 psi, but 18 shouldn't be too harsh if 12 is normal right?

[Billy Ricks]

Chris,
Get your preload (sag) set up right then start deciding how the damping feels. When you ride feel for things. If you know where there is a road with a washboard effect ride through it. Is the wheel staying planted and stepping over each bump in the series or is it chattering? After you hit a bump is it settling down quickly without bobbing up and down? As long as the ATF does the job don't worry about it.