"leak" from top of fork tube?

[CoconutPete]

Since I have 2 bikes in the stable now I decided to go back to a more traditional "tracker" look for Miesha (79' Special) since Smurfette will be the "low" bike.

This involved some front end surgery and a swapping of the top triple clamp.

When I yanked the rubber covers off the top of the fork legs, one was moist with fluid on the inside. One was bone dry.

Funny thing is - one is a little "oval" from I think someone overtorquing it at some point. That was the dry one. The "wet" one was un-mangled.

Condition of the o-rings on the 2 are identical. Fluid level in the fork tubes was identical when I filled them. The tops of the fork tubes were torqued identially.

Has anyone else experienced this? I suppose the nature of the preload spring and screw doesn't necessarily make for an air tight seal and I could have just gotten "unlucky" with a bump? Maybe?

 

[5twins]

I think there may be an internal o-ring seal on those adjuster caps, on the adjuster pin where it passes through the cap body. But I'm not sure how to get them apart. I never attempted it before.

 

[CoconutPete]

Hm... maybe a game of "swap-a-cap" is in order here...

 

[gggGary]

I've rust buster and beaten some REALLY rusted adjusters back to life. I think you could drive out the pin to get them apart but it's just a vague memory. work some stiff grease (Spray chain wax?) in there would be my first inclination.

 

[xjwmx]

If you mean the very top, the thing you remove to add fluid, it's hard to see how oil could get up that high? Maybe you laid that one on its side at some point and not the other? At any rate as a mechanic said to me once about a leaking fork..."well, it isn't going to all come out".

 

[5twins]

The fork oil is forced under pressure through the damper rod as the forks pump up and down. Oil sprays all over the place inside the forks. Granted, the fork caps aren't sitting under the oil level, but I'm sure they get their fair share of oil sprayed against them.

 

[kshansen]

The fork oil is forced under pressure through the damper rod as the forks pump up and down. Oil sprays all over the place inside the forks. Granted, the fork caps aren't sitting under the oil level, but I'm sure they get their fair share of oil sprayed against them.

You mean all your roads are not smooth as glass, like here in the north east USA?

 

[5twins]

That's where I am, and this winter took a toll on those roads. We didn't have a severe winter as far as the amount of snow goes, but there were lots of temp fluctuations and that played havoc with the road surfaces. Happens every year but this year just seems worse than others.

 

[kshansen]

I think you could drive out the pin to get them apart but it's just a vague memory. work some stiff grease (Spray chain wax?) in there would be my first inclination.

Well I just pulled the adjuster cap off one of my "spare" forks to have a look. The pin is pressed into a blind hole so no easy way to drive it out. I did give a tr with a pair for "Vice Grips" but it did not budge and I stopped before I did any real damage. Moving plunger/adjusting screww up and down it does feel like it has a seal like an oring dragging on it.

I suppose if someone did not have an option to replace the cap assembly one could carefully drill a hole opposite the pin and use a pin punch to drive it out.

 

[5twins]

Some of these caps do get trashed and go bad. The pin rusts inside the cap. I think that happens because water is allowed to get down in there, and that happens because the top rubber protection cap is missing. Unfortunately, you can't get the rubber caps from Yamaha anymore. MikesXS has repops but like most of their rubber stuff, they don't last but a few years. I watch for originals on eBay, mostly looking at misc. parts lots. The originals on my '78 are still in fine shape, as are most of the other originals I've run across over the years. The MikesXS repops on my buddy's bike are falling apart, lol.