Dirty fork oil syndrome

[Enmerdeur]

So does everyone think that the oil should be pristine after it has been used? Nothing looks out of the ordinary to me. I see the same results from every fork I have ever serviced before. You have surfaces rubbing together in there. There is going to be wear and tear.

[oldman]

I wonder if this can be improved by simply filing smooth the grove and bushing edges (very carefully) making sure the bushing is totally free to move as it normally should.

Just a though.

Filing on the edges of the groove would create a new problem. To much end play of the bushing, causing it to slide back and forth every time the fork tube changes direction of movement.
My question here is: Why is the wear on the inner tube bushing groove occuring in the first place? Soft material? Hardening process problem?
I can see what is showing excessive wear. Fork inner tubes have worn grooves where bushing rides, outside edges of inner tube bushings has coating worn away causing metal to metal contact with outer fork tube. Outside tube bushing has coating worn away on it as well allowing the metal part of the bushing to rub on the inner tube. Fork outer tube worn badly inside especially where the lower triple clamp pinches it and the coating inside the tube is scratched up causing the aluminum to show thru. Can't see well enough inside the cartridge tubes to see if running in the metaled fluid has worn them as well.

[Enmerdeur]

oldman

Do you have some photos of the bushings?

[oldman]

Yes, I have this photo of the bushing that fits on the inner tube that has the stepped edges in the above photo.
It appears to me that the bushing has been unable to rock and move to compensate for flex of the outer tube as it as it slides up and down within it. The shiny outer edges of the bushing is where the coating is worn away allowing metal to metal contact with the outer aluminum tube causing its inner surface to become scratched up and the coating to be worn away exposing the aluminum under the coating in places.

[bryanaverill]

I guess I am worried about this compared to my Honda and KTM experience where the oil was relatively fresh after a hundred hours. If there is a high wear part on my Beta, I'd like to address it.

OK, I see more information coming around the bushing, bushing groove, etc. When I said file smooth, I was thinking of just a smidge not enough to widen the groove. However, oldman, you are suggesting that the inner tube may not be very hard and the roughness is a result of wear rather than machined that way from the start. Therefore, different problem that what I thought. Your other comments and this long thread also suggest the bushing is too tight through the triple clamp area and that the outer tube coating may be soft.

That bushing looks perfectly normal to me. The anti-friction coating usually stops at the chamfer.

[Enmerdeur]

This is a photo of brand new bushings. They look the same as your "worn" bushings. This is normal design. It is a lead in taper on the bushing so as not to scrape the crap out of everything.

[Enmerdeur]

I have about 12 hours on a brand new set of Sachs CC forks. I am going to dump the outer oil and have a look see.

[twowheels]

Evidence of correct wear is seen inside the bushing ... the copper coating should be polished in the center. A corresponding ridge in the land will also show evidence of contact.

[oldman]

Twowheels, what is your thinking about the stepped ridge wear pattern on the lower part of the bushing groove in the photo I posted on page 9? Is this normal? Could this ridge be causing the bushing to snag and not rock or open and close as it slides down thru the inner tube causing stiction and a bind between the bushing and the outer tube?? The shiny surface on the top outer edge of the bushing suggest that to me?

Has anyone here seen a set of Beta inner tubes with a wear pattern like mine on the lower edge of the bushing cut out? Or seen a new set to compare my photo to? Or have a photo you could send?

[Enmerdeur]

To me your tube looks normal. I don't see any abnormal wear. The part on the center is just where the bushing makes contact.