93-94 USD's

[julien_d]

While I have my engine torn down I thought it would be a good time to rework the front forks. It looks like with my weight I can keep the stock springs, but I'm needing advice on what weight oil and how much. I am considering using ATF after reading some threads on that. I do not have the additional pages in my service manual that go over the USD forks used in 93/94. Does anyone have this information?

Thanks,

J.

 

[Matt90GT]

Is this on the 200 or 250 forks?

ATF while it works, I have called mobile and talked to a few people there that actually engineer the stuff. He said there is no CONSISTANT weight for ATF and it has a LOT of harsh cleaning additives to it. What does this mean? well not having a consistant weight is a problem. Sometimes might be like a 12.5w (which he said is probably closest if he had to give it a weight like suspension fluid) and sometimes might be a 7 or 15 weight. Not something I would want to deal with. Plus forks are designed for lighter weight fluids. Also with the harsh cleaners, it will make the seals leak faster and more wear on the bushings.

Ok, so that is what I know about the ATF. People use it and like it, but there is much better stuff out there. I always use the Torco RFF 5wt in the forks with great results. Only exception is the smaller mini bikes like my son's kx65 that calls for 10w20 oil in the forks. We use a variety of different fluids for indoor vs outdoor for him there.

For the level, with the springs out and forks collapsed, 3-4" from the top. Lower towards the 4 if you want plush and are lighter, more to the 3 if you are heavier and bottom them. Good rule of thumb on the single chamber forks.

 

[mudpack]

For the level, with the springs out and forks collapsed, 3-4" from the top. Lower towards the 3 if you want plush and are lighter, more to the 4 if you are heavier and bottom them. Good rule of thumb on the single chamber forks.

Isn't that backward?

 

[julien_d]

yeah, I figured that was probably backwards. I will assume that more oil will make them stiffer (ie: 3 inches from top), and less oil will keep them softer (ie: 4 inches from top).

Thanks for the tips. These are the KDX200 forks from a 1994. I've read that ATF is equal to about 7.5w oil.

 

[longshore58]

12 pages

Hey Julian......I have the supplement in my service manual for the USD's.....twelve pages worth........need a PM or email and I can scan'em and shoot them to you.

 

[longshore58]

PM recieved

They are on the way dude....... :nod:

 

[glad2ride]

Keeping the stock .30 Kg / mm rate springs? What do you weigh, five pounds? :-)

You may want to reconsider the spring rate.

Go with 5 weight oil.

 

[julien_d]

I'd say I'm 145 - 150 loaded up and on the bike. I've been reading what little I can dig up about 93-94 kdx200 USD's for months. Most of what I've seen recommends upgrading the springs if the rider is over about 150lbs. I am definitely not opposed to replacing the springs If it's going to be worth it. We ride tight trails, single track, a few decent sized jumps, no track time at all. Plenty of rock, mud, roots, and hill climbs. While the forks do feel a bit too squishy for me right now, I have rarely bottomed them out, and I'd hate to lose the ability to soak up the slow rough stuff. I guess I kinda thought I'd do clean oil, new seals, adjust the clickers, and see how they feel. Do you think I could go stiffer on the springs and retain the cushy ride through the woods?


Oh yes, thanks Longshore! Those scans are great! That's going to be an immense help, for sure.

J.

 

[longshore58]

good deal

glad to help .... :cool:

 

[julien_d]

No further advice on the springs? I've been reading the .40's from an xr400 will work. FRP has .38's and .36's.... What's good for a small rider like me in the tight woods?

 

[Matt90GT]

Best bet is to call or go online and look up the bike and run the spring generator

www.racetech.com has one. See if they list one for that model. But you need to get the correct spring rate for your weight. That is the easiest and best thing you can do for your suspension - run the correct rate springs

 

[glad2ride]

Honda XR400R springs will not work, if for no other reason than they are too long. With the 1995+ forks, they will, but they have more open space and spacers to adjust for the added length.

You may want to try some .38 springs with 5 weight oil. Save the ATF for your car transmission.

FRP Offroad and Race Tech springs will work in the 1993 and 1994 KDX200 USD forks. They are narrow enough to fit in the 41mm tubes.

 

[Tom68]

We ride tight trails, single track, a few decent sized jumps, no track time at all. Plenty of rock, mud, roots, and hill climbs. While the forks do feel a bit too squishy for me right now, I have rarely bottomed them out, and I'd hate to lose the ability to soak up the slow rough stuff. I guess I kinda thought I'd do clean oil, new seals, adjust the clickers, and see how they feel. Do you think I could go stiffer on the springs and retain the cushy ride through the woods?
J.[/QUOTE]

If your not bottoming out the're not decent size jumps you're hitting. Seriously though don't worry about soaking up the small stuff until you try some decent springs and valving and see how much better it is overall.

 

[QJA]

Hey guy's, I've got a 93 KDX200 with the blue USD forks so are finding this thread very interesting. I was wondering if longshore58 was able to send me the information please about the USD forks as you did for another member? I would really appreciate it if possible. Thanks.