I have a lower end of a shock from a motorcycle that has a slight imperfection on the inside - looking for help to bore/hone it until the shock has full travel. Willing to pay a little money to anyone that would know how to do this procedure.
Thanks,
Brian Kleinfall
Is the imperfection a nick or a dent/rise?
Sanding it(nick) down sometimes can be enough as long as it is no longer capable of damaging the seal.
If honed, it may require an over-sized piston seal are parts available?
It seems like there was an outside impact or possibly a slight bend - we think it’s just a dimple or two that need to be sanded down and polished. We tried honing - got slightly better but with the tool we had it would take hours - not enough outward pressure. I have the upper shock insert with the seal ring on it for testing. Luckily the imperfection is towards the bottom end of the travel - keeps it from traveling the last 3-4 inches out of 11 inches of full travel. So as long as the upper portion remains untouched the seals should all still be fine.
You may be better off replacing it.
3-4" on an 11" travel damper is a lot.
The 11" includes the compression and extension movements.
On street cars, the unloaded length is reduced by at least 25%, (usually more but not 50%) in travel once the car’s weight is on the suspension; with the last 1/4-1/3 of the remaining travel being helped by the bump stop.
Good luck on the honing. If you’re able to fix it, share your experience please.
Is it Ohlins or something?
Is it an inverted shock?
This is a picture of similar shocks. https://www.ebay.com/i/391899395700?chn=ps
I bought some used replacements I need to get this bike operational. I will continue to try to fix this shock. Let you know how it turns out.
That does look like an inverted shock.
Is the dent on the painted silver part? Is the a bump stop inside?
The dent is on the lower portion (painted silver) the insert (polished part) has a metal seal ring with Teflon on it that creates the seal. I am not an expert on these shocks by any means. Don’t recall a bump stop at the bottom of the insert. Here is a schematic…
https://www.yamahapartshouse.com/oemparts/a/yam/50044565f8700209bc78f6c3/front-fork
I may have missed it but can you fully compress the shock?
If you can without unusual resistance I wouldn’t worry about it.
It is an inverted shock with the shock body(chrome part) being the visually moving part. The metal ring on top of the silver part is just a spacer/grease seal to center the shock body(chrome part) within the housing(painted part).
The part between 12,37 & 10,35 is the actual piston which does the damping.
15.40 seems to be the bump stop but I can’t say with certainty.
If you’re going to DMS in the evenings, I can help take a peek at it.
I will let you know next time I am heading up there. Right now the piston moves down to that “dent” inside and then stops. Before we did the little bit of honing we did it would hit the spot and stop. After some honing - it hits a tight spot but gets past then hits another spot of stoppage. Attached crude pic of what I think has happened.
