Rattle in left fork after new seals?

pago cruiser

Joined
Jun 2, 2011
Messages
80
Location
Tucson
2002 ABS.
Just rebuilt the forks; have not done it for awhile. New seals, bush guide, bush slider, new bottom bolt with washer. Did progressive springs last time.
Left side has the damper rod.
Put it all together, added oil to 6.9", got the rod/cap connection done and screwed in the cap. Almost no problems.
Until I picked it up and set it aside. Has a distinct rattle. Sounds like the spring rattling; but it is obviously in some compression - the normal amount as exhibited by trying to thread the cap on. WTH?
Do not remember this from when I took it apart a couple weeks ago. All the parts in the pic are installed, in the correct order.
Other than the left side using a bit less oil than the right side (I assume due to the displacement of oil by the damper rod) , no problems going together.

Left Fork.jpg

Any ideas?
 
The left side suspension has the "Anti-Dive" parts down at bottom. Did you pull any of those for cleaning? (Your posted Illustration does not show the AntiDive parts. I will try to post my manual's Illustration, tomorrow.)
 
The anti-dive unit is on the right fork of later years ABS models.

The reassembled fork should not rattle. I’d have to disassemble and check everything again if it was mine, for peace of mind.

John
 
Hey Dave,
Thanks for the reply.
As John indicated, the anti dive on mine is on the right.
I unscrewed the cap off again, and if I hold it tight to one side of the fork tube, and shake (move rapidly maybe 3" back and forth while the fork is vertical) the entire assembly... no rattle.

Did some googling, and found some other people have experienced this as well - mostly after changing springs.
I dialed in pre-load a few fork oil changes ago, using straight-rate springs and PVC spacers. I'm positive the spacers are not mixed up, as one is about 5" and one about 7.75"

May have to go that route John - but I can't see what could be different. The cap is still under compression when putting it on; always a bit of a pain to re-install.
 
Last edited:
Well, finally figured it out... I think.
More than a few others have noticed this:
Fork Noise.jpg


The problem, is that the Race Tech constant rate springs were considerably shorter than stock; so you (or anyone who used these) has to make custom spacers. For my 200# weight, I ended up with 5.25" and 7.75". When assembled, the 5.25" spacer rides on top of the spring with the damper rod. Which has a little bit of slop in the horizontal. As in, if your oil level is set at 170mm, the oil level is below the joint. So when the fork is ...shaken... the spring impacts the fork tube ever so slightly.
Not seeing anything else amiss, I went to verify the oil level that I used - 170mm for a 2002 ABS w TC. Then I saw some other sites talking about a 130 mm level (5.1") per the Race Tech instructions. Upped the oil to 5.1" - and now the spring/spacer joint it below the oil level. Shake the fork again, and the spring/tube noise is ...almost...completely silent. Just barely perceptible. So I guess the oil viscosity dampens the motion sufficiently to eliminate the noise; and it is now always in an oil bath.
Dang. Only took me two weekends to figure it out.
 
Interesting. How does it ride with 2 more inches of suspension fluid in the fork tube than normal/spec’d? My Progressive Suspension fork springs instructions gave a generic/boilerplate fluid level (seemingly oriented toward dirt bike suspension) but specifically stated to use the brand and model’s spec if given/published (which the ST1100 has).

This issue was identified many years ago when Warchild first posted his article on ST1100.com about PS springs install and used the erroneous (5.5” vs Honda’s 7.5” spec) generic fluid level figure. Talk about a STIFF ride! Not to mention possible blown seals...

FWIW YMMV Yada Yada

John
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom