Many thanks to John_B for providing an excellent drawing I was able to make a collar on the lathe and have it installed now. Very good fit. I've just dropped the front fork tubes to match but it will be a couple of weeks before I can try the bike as I've left on a business trip. A few things I learned maybe worth sharing for anyone installing a collar, whether purchased or home made.
The rear shock spring was easy to compress to remove the stock retaining plates but inserting the collar requires more compression. I made a compression tool with 1/2" threaded rod but it wasn't really strong enough and eventually took it to a friend with a 20 tonne press. That worked.
No matter what way we looked at this we always came back to the same conclusion that (roughly) 1mm change at the shock equated to about 6mm change in height at the rear wheel, all considered. So using the apparent 35mm drop advertised by Metisse I dimensioned the collar to release 6mm more of preload. Roughly 6 to one. If I'd had the wherewithal to measure the seat height before doing the modifications i could confirm that this but using the published stock seat height (a hair over 35") I was successful as it is now at 33.75 inches without me on the bike. I can scratch both toes on the ground or flat foot one side without sliding much over, I’m quite pleased compared to the first 15000km without ever touching terra firma without sliding half way off the bike….
I also not the threads that state that there is a little free play in the spring after installing the collar drop but I still had a wee bit of preload, I don’t know how springs are made but I can only assume there is some variation in the length. Before I dimensioned the collar to 6mm release of preload I took some careful measurements and estimated that this would be the case, although it doesn’t match what others have experienced.
The front fork tube drop was baffling. To achieve a 35mm vertical drop as advertised by Metisse one would logically have to slide fork tubes up by over 40mm given the rake angle. Yet the Metisse instructions show 28mm from the top of the triple tree for the 1090r??? In stock configuration I measured the fork tubes to already 7mm above the triple tree so only 21mm drop to match Metisse instructions which would only lower the front by 16mm, not 35mm. Anyway, I dropped by only 24mm for a total of 31mm from the triple tree as I’m increasingly worried about clearance between fender and frame. I’ll try that and see how it feels.
I made the collar out of aluminum, not sure what grade because as usual I used whatever scrap was lying around the shop. Hope it stands up to the pounding...
A forum community dedicated to KTM 1090 adventure motorcycle owners and enthusiasts. Come join the discussion about performance, trail riding, modifications, classifieds, troubleshooting, maintenance, and more!