[ManicMechanic]

My newly acquired muscle has exhibited some leaking form the right fork. Not from any of the short rides I've had but both times it's been trailered. At the very least I need to service the forks and check whether there are any other problems lurking.

From what I've read I have to completely disassemble the forks to set the fluid level correctly. If that's the case I'll replace the seals and I'm looking at what upgrades I can accomplish at the same time.

So that's the back story. The bike has just shy of 18k miles so replacing fork seals seems a tad early. Has anyone else run into this or have any thoughts on what to check that might be causing the problem if it isn't the seal?

Any recommendations of fork oil, type, viscosity etc?

And as far as upgrades I don't think a full cartridge system is in the budget any time soon. I've seen several comments about racetech valves and a variety of springs so I'm re-reading those threads but looking for suggestions at the same time.

Any help will be appreciated.

 

[rbabos]

My newly acquired muscle has exhibited some leaking form the right fork. Not from any of the short rides I've had but both times it's been trailered. At the very least I need to service the forks and check whether there are any other problems lurking.

From what I've read I have to completely disassemble the forks to set the fluid level correctly. If that's the case I'll replace the seals and I'm looking at what upgrades I can accomplish at the same time.

So that's the back story. The bike has just shy of 18k miles so replacing fork seals seems a tad early. Has anyone else run into this or have any thoughts on what to check that might be causing the problem if it isn't the seal?

Any recommendations of fork oil, type, viscosity etc?

And as far as upgrades I don't think a full cartridge system is in the budget any time soon. I've seen several comments about racetech valves and a variety of springs so I'm re-reading those threads but looking for suggestions at the same time.

Any help will be appreciated.

Check for any lines or marks in the chrome as well as measuring the tube dia. Compare it to the left one. On mine the right tube was in places -.0015 smaller then the left tube. The seal worked so so but every once in a while it would leak and then not leak for a while. Just not enough seal pressure on the tube to work well. New tube and all is good now. The Muscle and Dx inverted are exactly the same forks, just the color. I'll leave upgrades to others as well as oil flavors. Oh, stay with OEM seals as they are the better ones. The kit also comes with new bushings to completely freshen the assembly(s)
Ron

 

[ManicMechanic]

Check for any lines or marks in the chrome as well as measuring the tube dia. Compare it to the left one. On mine the right tube was in places -.0015 smaller then the left tube. The seal worked so so but every once in a while it would leak and then not leak for a while. Just not enough seal pressure on the tube to work well. New tube and all is good now. The Muscle and Dx inverted are exactly the same forks, just the color. I'll leave upgrades to others as well as oil flavors. Oh, stay with OEM seals as they are the better ones. The kit also comes with new bushings to completely freshen the assembly(s)
Ron

Thanks Ron. I did check for obvious nicks, grooves etc. on the sliders. I didn't find any but i did find a lot of crud built up on the inside of both forks but much worse on the right. It took a little effort but cleaned off easily enough.

I will take some measurements to compare side to side and at different points in the stroke.

 

[rbabos]

Thanks Ron. I did check for obvious nicks, grooves etc. on the sliders. I didn't find any but i did find a lot of crud built up on the inside of both forks but much worse on the right. It took a little effort but cleaned off easily enough.

I will take some measurements to compare side to side and at different points in the stroke.

Crud could be the culprit for sure as it packs up near the lip detracting sealing effect. Go through the normal checks anyway to be sure, so you only do this once. I kitted my right one early on and the damn thing still seeped. Not until I measured it, I found the real cause. Good old HD quality control or too generous mfg tolerances bit me in the ass.
Miking anywhere from the axle block up a to about an inch above where the seal would sit with at full extension is fine. The tubes should measure 1.691" -.0000
+.0005
Above that, the chrome is just there and does nothing anyway.
Less then 1.691" DIA, sealing ability drops off. There is a fair amount of play in the bushings, even new so if the tube is pushed to one side of the bushing the concentricity of the tube to seal is lost, so if the tube is undersize some the lip can just about break contact with the tube. You'll see what I mean once you dive in.
Ron

 

[ManicMechanic]

You'll see what I mean once you dive in.
Ron

Thanks, I'm sure I will...

I remember reading one of your posts about having to replace one side. I'd prefer to only do this once.

I honestly didn't catch the crud until after i made the post. i checked but i guess not far enough down.

 

[Larry37807]

I would also try the Seal Mate device to clean the seals first before you replace them. Most cases are solved easily with a Seal Mate.

 

[ManicMechanic]

I would also try the Seal Mate device to clean the seals first before you replace them. Most cases are solved easily with a Seal Mate.

Honestly I've lost quite a bit of fluid out of that fork and I have no idea what condition it was in fluid-wise before i got it. If I have to take it apart to service it I'll replace the seals at that time and probably throw the whole kit at it and some new springs.

I will pick one up to keep it clean going forward though.

 

[rbabos]

Honestly I've lost quite a bit of fluid out of that fork and I have no idea what condition it was in fluid-wise before i got it. If I have to take it apart to service it I'll replace the seals at that time and probably throw the whole kit at it and some new springs.

I will pick one up to keep it clean going forward though.

Last resort only as they can damage the seal too. Sometimes they work, but usually for the dirt bike crowd where dirt is the norm.
Ron

 

[ManicMechanic]

Any suggestions on fluids or where to get them?

I think I'd like a bit more dampening than the stock HD type E.

I've seen several conflicting accounts of what the viscosities are. In two different (apparently HD) docs its reported as 5wt in one and 20wt in another.

Sent from my ONEPLUS A5010 using Tapatalk

 

[rbabos]

Any suggestions on fluids or where to get them?

I think I'd like a bit more dampening than the stock HD type E.

I've seen several conflicting accounts of what the viscosities are. In two different (apparently HD) docs its reported as 5wt in one and 20wt in another.

Sent from my ONEPLUS A5010 using Tapatalk

Type E is actually a hair over 10 weight regardless of internet claims, then again I'm on the damn internet too. True fork oil viscosity is measured in centi-strokes. TypeE works out to about 11 viscosity. Any way, the issue with these forks is HD managed to fk it up in two aspects. Damping is actually harsh even with TypeE for normal control and the spring rate is too weak to prevent excessive diving on hard braking.
You can go with the heavier SE fork oil which will slow the dive some but at the same time it will be rougher or harsher in normal bumps because of the damper and thicker oil. The only real true fix or upgrade is a better damper valve system and slightly stiffer springs. I just upgraded the rears to 444s and had a chance to ride it recently. While I felt no jolts in the seat like I use to, I can really feel it in the front end now. Before, I just got beat up from both ends. LOL.
Ron