Hey folks,

Hope everyone had a good weekend. Got around to changing out my fork oil, I figured after 5 years and many miles it was time.

I couldn't believe how black the old fluid was. Used some ATF type F to clean them out, then topped them up with 18 oz each of a 50/50 mix of Lucas 20 wt and 15 wt synthetic fork oil. Curious to see how my "17.5" weight fork oil will do under heavy load (I also have progressive springs and a washer for preload in the forks).

So...now to my question...upon re-assembly I was careful to line up the forks with the old alignment marks on the lower pinch bolts. Got everything bolted up and my left fork cap is just a hair higher than the right in the upper tree. It's tiny but perceptible.

Do I need to strip her down and realign or should I be good to go?

I'm a little frustrated if I have to pull it again because I measured from the bottom of the fork to the same point on the lower pinch bolt assembly and they were exact prior to putting the bars back on.

Thoughts?

Thanks!

George

I don't think there are any alignment marks. I put mine the same at the top triple tree. There can be a slight difference in spring length.

George, I don't know about the height being off. My left one is a hair higher.
I think that oil is a bit thick for forks. IMHO.

It is not the end of the world, and will probably work fine, but for future reference, measure from the top face of the lower clamp to the top of the tube clamp and duplicate that dimension on re-assembly. It is not unusual to have a couple mm variance in the full extended length, but your geometric base is above the lower clamp, not below.

Shores wrote:
I don't think there are any alignment marks. I put mine the same at the top triple tree. There can be a slight difference in spring length.

Hey Shores, thanks - by "alignment marks" I meant the faint lines on the fork from where they were attached before - kind of a reference (since they were perfectly aligned previously).

Spring length - good point. If I'm a touch off is that a safety issue? probably no more than 1 mm

JEastonjr wrote:
George, I don't know about the height being off. My left one is a hair higher.
I think that oil is a bit thick for forks. IMHO.

We shall see! I like a stiff ride and I'm pushing 250 lbs - and usually riding with my wife who's 125, plus loaded trunk and saddlebags.

Thanks for the feedback on your forks!

Once I get it out for a ride I'll give a report - hopefully it isn't too thick, if it is I'll be changing it again soon

jd750ace wrote:
It is not the end of the world, and will probably work fine, but for future reference, measure from the top face of the lower clamp to the top of the tube clamp and duplicate that dimension on re-assembly. It is not unusual to have a couple mm variance in the full extended length, but your geometric base is above the lower clamp, not below.

Thanks JD, I'll remember that for next time (hopefully not in the next week or two if I got carried away with the heavy fork oil LOL)

1 or 2mm is nothing to be concerned about. As far as your fluid expiriment, I'd be more inclined to make sure your rebound is not too slow. Compression wise, it'll probably be OK, if not a little stiff on smaller bumps. People HAVE used 20W in the past with the stock tubes. Have not ridden it myself, but just based on the dynamics of the stock fork, rebound would be where I would focus. Indications of excessive rebound damping would be the front packing down on bumpy curves, wbicb will have the charateristic of having to correct wider as you hit the bumps. Deeper compression of the tube tightens the turn radius. The other place is braking over ripples. Excessive rebound damping will have the characteristic of wheel hop, where the fork is not extending the fork back out fast enough on the down slope of a bump. It can be felt as a chattering effect, both in the bars and in the lever, as the pressure required to stop the front wheel will spike up and down as the tire goes in and out of contact with the road. If you check for this, do it solo, in an area where the stop is not mandatory, and you can let go of the brake to recover if you experience a lockup chirp or something. I don't expect you to have a big issue, but I would do the experimemtation up front. Better at a controlled time than in the moment to assess the performance.

Yep that stock oil is NASTY, and that's all I know about forks. Mine are in Dr. JD's ICU.

So I have about the same weight on the bike. 10 wt good or should I go higher?