Excessive wear on 40mm front fork

[rutgery]

The fork tubes from my 1989 Cali 3 where worn through the chrome when I bought it with 65000km. I’ve replaced them last summer and used them about 800km. Also polished the insides of the sliders. The dampers didn’t do it for me so I pulled the front end to replace them, and saw the chrome of the left tube was worn again very much for such a short time.

The first picture is from the old tubes, second from the “new” 800km old ones and the last from the slider

Is this a known problem and/or does anyone have a fix?

[gearman]

Maybe your sliders are bent.You have the correct oil. I always use atf fluid and never had a problem.Good luck

[acguzzi]

I'd suspect alignment, there is an assembly process to make sure the forks move freely. Is there a fork brace on that model? That can aggravate things if the forks and axle aren't quite aligned.

[Chuck in Indiana]

Old Chinese philosopher Som Ting Wong sez: "Look above, grasshopper." 

[rutgery]

Thanks for the quick replies! I should have mensioned the forks were refilled with 150cc Eni 10W fork oil as mentioned in the workshop manual.

I'd suspect alignment, there is an assembly process to make sure the forks move freely. Is there a fork brace on that model? That can aggravate things if the forks and axle aren't quite aligned.

Alignment could definitely be the issue, but the wear is on the front side of the forks, which would be weird for being caused by alignment, no?
I don't believe the sliders are bent as the bike has never been involved in a crash.

[Chuck in Indiana]

Well, the point is, nobody else has this kind of problem..so.. *something* is going on with your bike.

[acguzzi]

loosen the top clamp, remove the fork caps and see if the wheel will slide up and down easily.

[wirespokes]

Did the problem get fixed?

Where'd you get the replacement tube?

[rutgery]

Did the problem get fixed?

Where'd you get the replacement tube?

I’m currently working on the v7 again, mounting Brembo p04 calipers and cast wheels. I’ve also fitted Honda rc36 internals into my 40 mil forks.

When everything’s back together I’ll rotate the lh worn tube (why I started this topic) to the rear as it doesn’t leak yet. I’ll pay close attention to the alignment when assemblying it and will continue checking for wear when riding.

The forks were bought at stein-dinse. I do not know if this is (part of) the cause, it wouldn’t surprise me as some(!) other items they carry are very poor quality.

I’ll update as soon as possible but this might take a while

[wirespokes]

I've heard that before about SD. I've gotten a few things from them - needles and jets, clutch parts - and they were fine.

I was considering getting their fork tubes but was warned against them as being poor quality chrome. The photo of a bad one showed all sorts of pitting, but yours don't appear that way. I've seen the same kind of scuffing on airhead fork tubes when they're misaligned or bent, and they have excellent chrome.