43mm Fork Oil weight - any effect on rebound?

[Chuck Marler]

I put stiffer fork springs in my 95 KDX-200 - (43mm cartridge front forks) Had some REALLY, Really, really, scary moments riding my new pogo sticks through the whoops, so I have three questions if anyone knows.....

Now I know that's a compression damping adjustment on the bottom, and I was running 5W fork oil. I know, I know, I read all the archived posts and found "no rebound damping adjustment" but theres' gotta be a rule of thumb, and I didnt' see a firm agreement from the KDX tech-heads posting in other threads.

1. Will a heavier fork oil, say 10 or 20 weight, give greater rebound damping? I reckon it will add compression damping also, and I can live with that until I send them out.

2. Will oil level have any effect on rebound damping?

2. Should I just throw away these riding pants?

-Chuck

 

[dirt bike dave]

1. Heavier oil weight will make a big difference slowing down rebound. Type F ATF is approx. 7.5 weight and cheap if you want to experiment with that. I don't think you would ever need or want to go more than 10w.

2). Oil level primarily effects bottoming resistance and fork stiffness in the latter part of the travel. Use oil weight to control rebound on old style forks w/out rebound adjusters.

3. If you want your pants to last longer, get your forks revalved and buy a steering damper!

 

[Chuck Marler]

Thanks Dave,

Thank you sir <tipping hat>... Eventually, I'll get them revalved by Race Tech... until then, I'll adjust rebound damping with different oil weights. Thanks again.

*Amusing Anecdote Alert*

I have a WER steering damper, which I'm sure saved me several times on those new stiff springs. Naturally, at Pine Hill I steered the conversation towards suspension after the event, just trying to figure out this rebound thing. So I am listening to Greg "money is no object" Lippoziski. I forget who did his suspension but I was all ears right up until he described the "plushness" adjustment. After I laughed at "non technical" jargon, he dragged out the tuners adjustment spec and showed me there is also a "suppleness" adjustment.

 

[canyncarvr]

Re: New springs and pogo sticks

You're saying there is a lack of rebound control? They rebound too fast? I don't know for sure what 'pogo stick' means 'cept it sounds bouncy.

What for springs? What oil level?

A (bad) example: You follow RaceTech's rate charts (stiff!) AND put it back together with the 90mm oem spacer and a 100mm oil level.

THAT'S going to be pretty stiff! Forget rebound 'cuz there won't be diddle for compression to rebound from.

Keep in mind that the clickers are going to change lo-speed action while the valving/piston setup is going to work on the hi-speed part of things.

Yeah...some tuners love to magick their trade. From the difference of hi speed to hi-speed (the '-') differences, plush/supple/etc. While there is no doubt there is a good lot to learn and understand they (most tuners) do their share of making it more difficult.

BTW, RaceTech uses GoldValve technology while others tend toward the Pro-Action setup. Some use proprietary valves, some refashion (grind on) the existing valve. Not all systems are created equally. Do the research needed to satisfy yourself with your decision. Don't just 'send 'em off' somewheres.