KDXRIDER.NET

I need to change the Fork oil in my '91 KDX 250 but I need a little help. I have a manual, but it is for KDX200's. (Yeah, I know I need to get a KDX250 manual) It works for almost everything on the 250, except the forks. The 250 has USD forks, unlike the 200's. I need to know where the drain plug is and the volume of oil that the forks need. Everything else, I can figure out from my manual. Also, I am planing on using ATF in the forks. I have read from many people that it works very well. Anyone else have any input on ATF in forks? Thanks

Where'd the 250 guys go?

Sheesh...this is pretty rotten 'customer service'.

Re: 'Where is the drain plug?'

Most forks don't have a drain plug. The 'A' 'H' OEM KDX forks do. Dump the oil out the top after you have the cap off.

Re: '..volume of oil'

The oil volume isn't the point..and you rarely measure it that way. You set the new oil to a particular level from the top of the fork tube. Depths vary by personal preference..from 100-120mm. That's with the forks fully collapsed, spring out. Fashion something that sucks (a big syringe, fer example) to a piece of tubing of the correct length, overfill, suck out the extra TO the level you cut the tubing to.

Re: 'ATF'

I use Mobil1 ATF. Works fine. Recommended for 'home fills' by MX-Tech at one time. Don't know about Dexron or 'regular' ATF.

Canyncarvr - Thanks for the information. I appreciate the time you took to thoroughly answer my question. I am still fairly new to the KDX world and it is nice to be able to seek advice of knowledgeable veterans.

Actually...I didn't take the time I generally would to beat a subject to death. I just hit the high points.

I don't KNOW there are no drains in the KX250 fork..but I don't SEE one in the microfiche at ronayers.com on a '91.

It might be helpful to take a look at the USD fork info on this site...although it is not a one-size-fits-all disassembly. The online microfiche might be more helpful.

If you don't take 'em completely apart, it's probably a good idea to take the cap off, spring out, drain 'em, then 'cycle' some clean fluid through them to do a half-fast flush job. I've used kerosene for cleaning fork stuff..but when the fork pieces were apart. Not so good an idea if you're working with a fork that just has the spring out.

When you're ready to put the new fluid in, be sure to get all the air out..pump the forks and the rod until you don't hear any bubbles. Maybe tap the forks with a rubber mallet to loosen up stuck bubbles, pump it some more.

Setting the fluid level when there are trapped bubbles is a waste of time.

If you haven't done this before, you will likely have some questions. Hopefully they will be addressed sooner'n this one was.

Another tip: DO NOT try to loosen the cap with the top clamp still tight. Loosen the top clamp bolts, bottom bolts still tight, THEN loosen the cap. That way you won't have to try holding them in a vise where a slip of pad might damage your fork.

On reassembly, 10ft/lbs on the bottom clamp is fine. The specified torque is too much. 12ft/lbs on the top clamp is fine.

I have the same bike, but my manual is at a buddy's house. I run ATF in all my forks. Works great, imo. I dont remember what the fluid level should be though....

It should be 569 +-4 ml of 5W fork oil.. I mixed it to 7,5W and gave few ml more and its pretty hard.