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Old 05-06-2012, 02:48 PM   #1
andrewinuk OP
Joined: Aug 2010
Location: London, UK
Oddometer: 16
R100R to RS.... how much do i need to raise the rear end?!?

OK... this is probably not the first question someone usually asks during this transformation but i have made a few modifications that i want to keep..... primarily a sharper steering angle compared to standard.

when i first got my 1992 R100R i didn't really like the way it handled so dropped the triple clamps down the forks so the legs were the same length as my previous RS, a move of 38mm, added some clip ons and now had the bike exactly as i wanted it with it's S style bikini fairing.

but as i now have a 900ss for trackdays the R100 can be focused more on touring..... which could only mean one thing, yes an RS fairing!

trouble was that:

1. the clipons didn't fit in the fairing
2. the RS bars do not allow the forks extended above the triple clamps enough even with an extra set of bar raisers
3. i have an expensive and much loved top spec wilbers rear shock set at R100R length that i am compelled to keep

so what to do?!?

easiest option seems to be to raise the rear by extending the shock mount by ¾ of an inch to get to GS dimensions (and wear out my drive shaft
L ) to set the bike up Boxer Cup style a little further off the ground. there seems to be 2 options (as i didn’t want to shorten the forks and it is cheaper than raising the engine if i do more trackdays on the BM)

1. extend the shock mount with some welded tabs
2. fabricate a bolt on extender

i am in good hands with the engineering but i wanted a more maths focused person to advise on how high the rear needs to go to get RS style angles on the steering as i am rubbish at that sort of thing..... any thoughts? Any other options??

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Old 05-07-2012, 05:13 AM   #2
Beastly Adventurer
AntonLargiader's Avatar
Joined: Aug 2003
Location: Charlottesville, VA
Oddometer: 4,312
You need to go up a LOT. The R100R is very raked out, and I have also seen how there is no room at the upper clamp. BTW even with the forks not raised, you might find that the controls and cables foul the upper clamp once you have the RS bar. Or even the K-RS bar. It's really tight in there.

If you're feeling adventuresome you can go with a smaller front wheel. I'm working on that for my R100R; a 17" rim with a 110/70 tire. I already have a GS shock and dropped clamps, and I want more. :)

The real solution is to cut/weld/fix the head tube angle buy a Hypermotard.
Anton Largiader
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Old 05-07-2012, 03:28 PM   #3
andrewinuk OP
Joined: Aug 2010
Location: London, UK
Oddometer: 16
interesting option with the smaller front wheel.... but i am trying to keep on a budget with this one so if raising the rear doesn't "fix" it, i'll shorten the forks and cut my progressive springs.

and totally agree on the space issues, in the photo above the shiny wilbers, is a photo with RS bars and 2 old style bar raisers from an RS/RT.....and there still ain't much room!!

hypermotard is part of the plan one day, based on converting my RS/R to a GS.... with a short front end of course

i'll post the outcome of the work in a few weeks.

in the interim, if anyone has a handle bar based solution, i'd love to hear it!!
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