35mm Film Trick - Front Fork Seal

[Liamfm]

Hi,
I just picked up a 96 KDX200. It has a few issues I'm dealing with, the biggest of which is that the boots on the front forks were torn and there is a VERY small amount of oil inside the boots. I'm not sure if the seal is leaking or if this is normal.

I'm going to order replacement boots, but wanted to know if I should replace the seals too (left side seemed worse then right), or if I should try to 35 mm film trick I've read about on here.

If I should try the film trick is there anything I should know? Do you slide the film down with the shocks still on the bike, or do I have to remove the dust caps, etc? I'd like to just unbolt the forks enough to get the new boots on, but want to make sure the job is done right.

Any help is appreciated - it's been a long time (15 years) since I've ridden a KDX!

Thanks

 

[SS109]

The film will work great but so will an .002" feeler gauge. That is what I use.

Get the dust boots out of your way and then use a rag to wipe any loose dirt away from the seals. For good measure I used some compressed air after using the rag. Then slide the film/feeler gauge between the seal and the fork leg. Be careful and do not force it as it should slip between them with a little pressure. Work it around the seal slowly and lift while doing it to bring any dirt up. After going all the way around remove the film/feeler gauge. Wipe with rag and then install the dust boots. Done!

Good luck and welcome back to the KDX!

 

[Liamfm]

Thanks - so to get the dust seals out it looks like (from the service manual), there is a snap ring of sorts. Then do the dust seals come right out (lift out), Should I plan on replacing the dust seals at the least, or can I reuse them?

Thanks - sorry lots of questions.

 

[julien_d]

No snap ring holding the dust boots. The snap ring holds the actual seals in there, you do not need/want to remove that unless you are replacing seals.

 

[Liamfm]

So I already have the dust "boots" off, but the expanded diagram shows a 92033 Snap Ring, then 92093 Dust seal, then finally the 92049 Seal Oil. So I guess my question is, should I be removing anything other then the fork boot (accordion plastic boot) before I try the .002 feeler gauge?

Thanks for the help! Bike, Car, Trucks are so much easier to do the DIY stuff with the internet! Didn't have these resources last time I had a KDX.


Liam

 

[ellandoh]

dust seal should pull down with a little careful prying. return to post #2 . note, this trick is a 50/50 shot at curing the problem.

 

[Liamfm]

Okay, so I'll try to pull the dust seal out, then use the feeler gauge to clean around the seal?

Ellandoh, you say pull "down", but I would be pulling up to get the dust seal out. My forks are not inverted.

If the problem isn't cured by this I'm assuming I'm looking at a full rebuild of the front springs/forks.

Should I look to change the fluid or top it off while I'm in there trying to clean the seal? The service manual shows a special tool to measure the amount of oil. What's the DIY way?

Thanks (again!)

 

[ellandoh]

oops sorry, how about pull out...LOL
only thing you will need for sure if this doesnt cure, is seals and oil and some tools and youtube....hopefully


youtube has instructional videos for seal replacements including oil change and measurement that are great for twin chambers, they also showed home made "seal driver" made of pvc pipe. i would expect you could find some for yours also

 

[reepicheep]

And aside from fabricating that special tool or two, a complete teardown of the forks isn't that bad on this bike, and new seals are cheap. If it were me and I knew there was damage, I would just replace them.

 

[Liamfm]

Thanks guys - I'll try to clean it and save the $30. If that doesn't work I feel like I can probably tackle the repair.

I appreciate the help!

 

[Liamfm]

Can anyone tell me what a fork leak is like? When the seal goes is it a gusher of a leak (compression sends oil everywhere) or is it more like an oily film. The reason I ask is because there were no dust seals (wipers) on my forks and I wonder if those alone will cure my "problem". I am not loosing any significant amount of oil, but the PO had managed to not clean the boots and there was some oil/dirt/water that was running down one of the forks. Again, not any huge amount of oil.

I've got new wipers on the way - perhaps the seals are just fine???

Thanks,
Liam

 

[2strokerfun]

Wipers just keep the seals from getting crud in them. They won't fix an already leaking seal and it sounds like you already have a leaking seal. They usually are slow leaks and the first sign is often just a ring with dirt on it where the wipers bottom. If you have oil on your fork, you have a leaking seal. I've never tried the film trick, but if you just have small crud in your seals, I've read many times that it works.
Personally, I just change the seals, and sometimes replace the wipers. These days I also run a set of seal savers over the wipers.

 

[domino dave]

Liam - I agree with 2strokerfun ... If that bike has been run with bad boots and you are seeing any amount of fork oil , you have fork seal problems that will continue or get worse. IMO using film or a feeler gauge is like the magic potion on TV. I say this from my personal experience. I am no more than a decent backyard mechanic, and trust me, a fork seal job is easy. If you need any help just come here and ask .... Dave

 

[julien_d]

If dirt gets trapped in the seal, it will leak. The film trick, sandpaper, or masking tape will remove the material from between the seal and fork tube, and the leak will stop. It's pretty simple really.

If the seal is damaged or worn out, this obviously will not help.

 

[Liamfm]

Based on the comments here, and the lack of routine maintence by the PO I've decided to have the fork seals changed, oil changed, cleaned, new dust seals, and new boots. The 35MM trick might have worked, but the reality is that they probably needed an oil change and cleaning and might need a new seal. I'm going for the "do it right and don't do it again for a while"...

Thanks all! Hopefully the shop can get to them this week.

 

[sr5bidder]

the SHOP? :yikes:

 

[Liamfm]

Yeah, I'm a DIY'er most of the time, but every once in a while I get something that I don't want to tackle. If I had someone who could walk me through the first one in person I would have done it... Head gasket? Sure. Fork seals... maybe not. :-)

 

[reepicheep]

Mechanics have to eat too I suppose. :)

The fork job wasn't bad on the KDX, at least not once you weld up the special tool with the nut on the end of a tube. On the other hand, if you take the fork tubes off the bike and put them on the dealers bench, I would think the labor should be less then two hours (and maybe only an hour). And then you aren't running hither and yon trying to find the seals, crush washers, oil, o-rings, and guessing at the right measurements.

 

[Liamfm]

Yeah, I was quoted 1hr to do both forks. Maybe a bit more if they run into problems. To me, the $60 to have it done right (plus parts) is better then me buying or fab'in up the tools to possibly mess it up myself :-)