Topic: Forks topping out after rebuild

[evanphi]

I set up my progressive springs with the recommended amount of fork oil from the factory manual (rebuilding from dry), as well as the 1" PVC spacers. My forks are now topping out (hearing a ka-thunk after going over a longer bump with some speed). Is it just too much preload for my weight (170lbs)? I just find the ride is overall more harsh than before.

Should I just try running without the spacers to reduce preload?

[flybox1]

what weight fork oil, and how much was added to each fork?

[evanphi]

10W fork oil, 225mL per leg.

[przjohn]

I have had the same problem with too light a fork oil.

[Jerry Rxman Griffin aka MuthaF'er]

I added 155ml 15W fork oil to my 75 F with the Progressive spring kit after complete rebuild and it's banging too.

[NobleHops]

Did you measure sag after your spring and spacer work?

[Stev-o]

I didnt use the spacers on my K4.

[evanphi]

I took the spacers out last night and I can now actually bounce the forks with my body weight.

Looking at some specs... Progressive gives all the same springs for early to late model bikes. The later Fs had 1" longer fork tubes. I think the 1" spacer should be left out for earlier bikes, then.

[Steve_K]

I had to use 20 weight fork oil in my 750 to stop the clunk or topping out.  The progressive springs were hard for me to install with the right preload, but it was worth the effort.

BTW, did you pump the fork a few times to for the air to be flushed out of damper and recheck the fork oil height?

Another clunk can come from the brake caliper arm.  It can move up and down.  The small pivot can be adjusted tighter if needed.   It is just a possible point on the clunk and not related to the fork action.
Steve

[NobleHops]

The suspension should be resting about 1/3 of the way through its total travel with you on the bike, dressed to ride. Unweight the front end, lightly install a ziptie around the fork tube right against the dust seal, then gently put the bike back on the ground and mount it. Unweight it again and then measure the distance the ziptie traveled on compression. That's your sag. What is it now?

There's a short top-out spring that is sandwiched between the top of the damper rod and the bottom of the fork tube. Was that reinstalled in the proper location?

[evanphi]

The suspension should be resting about 1/3 of the way through its total travel with you on the bike, dressed to ride. Unweight the front end, lightly install a ziptie around the fork tube right against the dust seal, then gently put the bike back on the ground and mount it. Unweight it again and then measure the distance the ziptie traveled on compression. That's your sag. What is it now?

There's a short top-out spring that is sandwiched between the top of the damper rod and the bottom of the fork tube. Was that reinstalled in the proper location?

Yep everything is installed correctly.

With the spacer I had ZERO sag. None. Too much preload. I could barely compress them with my body weight.

Without the spacer it feels more like the stock springs, just a little bit of sag. The springs sit at the top of the fork tube without the cap on, so the cap adds all the preload I need.

[NobleHops]

How much sag?

[evanphi]

I'll check it specifically tonight, but it wasn't too much.