Fork seals leaking - Only when stored?

[295566]

This one is strange to me. Hoping that someone who's more enlightened than I can explain why this might be happening.

The fork seals on my GPZ will seep fluid, sometimes enough to accumulate a small puddle (1-2 inches on the ground), but ONLY when the bike sits for a period of a few days or more. If I wipe all the fluid off, next time I ride, they're still dry. Then, if the bike sits again, it will leak.

I've replaced the seals twice before, the first time did just a fluid/seal change. The second time I said fuck it, and replaced the seals, bushings, dust caps, everything! Thought that fixed it, but nope, it's still leaking, but like stated, ONLY when the bike sits.

It seems obvious to me something funky is going on, but in my mind, if the seals were truly blown, the repeated up/down motion of riding would cause them to leak. But that's why I'm posting! Anyone seen anything like this? Things to look for? no obvious damage to the fork tubes, either time I pulled them apart... no pitting, scratches, etc. Used OEM Kawasaki seals, as well. Though I ordered a third set of seals, this time from All Balls (used their bearings and have been very happy with their quality), for roughly 1/3 the cost of OEM. So we'll see...

 

[2strokeYardSale]

When they are used they get warm and expand, thus sealing better? When they sit they get cold and contract, thus not sealing?

 

[kuksul08]

Are you sure the oil is leaking from the seals and not the drain bolt or damper rod bolt?

All Balls fork seals have a very bad reputation... but I guess if it's already leaking then why the hell not?

 

[295566]

Are you sure the oil is leaking from the seals and not the drain bolt or damper rod bolt?

All Balls fork seals have a very bad reputation... but I guess if it's already leaking then why the hell not?

Yup it's definitely coming from the seals, as the it drips down the leg, caliper, and hits the ground.

Didn't know about all balls fork seals... Hope they will fix it though.

 

[stangmx13]

fork tubes can be out of round, contributing to leaks. tightening triple clamps too much can make it worse. any bend in the tubes can cause a leak too.

SKF seals are the best of the best. they seal well, last a long time, and have very low friction. but thats prob overkill for a street bike.

 

[Busy Little Shop]

Run your fingers over chrome slider and note any nicks that will cut and
prematurely end good sealing... gingerly use a fine flat file not a coarse file over the
high points to blend...

 

[Starpower]

Guessing a nick on the tube on the lower end. When on the bike the forks compress and this nick that is likely right at the seal line at rest is now below the seal leaving the seal on clean tube and not leaking. Have someone lift the bars a bit to unload the forks and feel around for the flaw and treat as mentioned above. Good luck!

 

[Biga]

Before you go to the trouble again, try this... worked for me...
https://www.youtube.com/watch?v=-D9ygYuSDiM

 

[295566]

Thanks for the suggestions all. I think I may pull the forks off the bike to do a thorough once over, once again. Hopefully no nicks, but you never know.

Worst case scenario, anyone have a good source for new fork tubes for older bikes?

 

[Junkie]

Racetech lsits tubes http://www.racetech.com/ProductSearch/12/Kawasaki/GPz900/1984-86

Chrome Fork Tube (each) FTNK 0050138 $183.25

no clue how good they are

 

[295566]

I should mention, my GPZ doesn't have a stock front end. It's a swapped front end from a 95+ ZX11D. Unfortunately don't see those listed on Racetech's website, but I'll do a bit more digging.

 

[Maddevill]

Use OEM seals , especially on Kawasakis. They seem to work best.

Mad

 

[kxmike]

I've actually had good luck with All Balls seals on a number of different bikes.

 

[bikewanker]

Used these folks around the GPZ era.
http://franksforks.com

 

[295566]

I've actually had good luck with All Balls seals on a number of different bikes.

Good to know. An interesting thing to note is that the design is different than OEM; there's a double lip seal on the oil side, similar to an X ring almost? And then there's another seal on the top end. So there's in total 3 seals, whereas the OEM unit only has a single seal on the oil side.

Used these folks around the GPZ era.
http://franksforks.com

I've heard of them before... interesting that it's all custom made. In my mind that means $$$ but will keep that in mind!