KDXRIDER.NET

I'm going to tear down my KX forks and replace the seals and put fresh oil in the tubes this weekend. Is 5w the appropriate weight oil?

If the spring rate is right and valved right ....then yeah...

Only one way to find out then I suppose

I used 7wt. Oil. The spring rate on the KX125 is slightly less than I was hoping for.

Those seals did not go in easy either, glad I have a seal driver.

Oil is easy to change after the fact so i'll start with 5w and see how I like it with the (hopefully) stock valving and springs. The stock springs are .38's so they should be the same or softer spring rate then i've got in my forks currently. No seal driver here i'm going to try the PVC coupler cut in half method to drive them in.

That should hopefully work. I don't know if my seals were out of tolerance or something but they took a considerable amount of force to get them in. Much more force than I was comfortable with, and the dust seals were even worse. They do not stick or leak, so I figure they are ok. Time will tell.

My preference is to get the correct weight springs so the forks are at the correct ride height and not chewing up travel with sag. Oil weight won't help with that. As far as oil volume; start at no more than 100 mm. I ended up at 120mm 5wt. I thought I saw an ebay auction for Racetech fork springs for KX. You may want to check that out. Race Tech seals are also heavy duty but they do take a bit of time to break in. New, they have quite a bit of stiction, so don't panic over that with new seals. About 100 miles to seat them proper.

I'm going to start with the .38's that are in there and go up in spring rate if necessary.