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probly wreck it
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49 Posts
Discussion Starter · #1 ·
Hey all, been a fan of the site for a few years. It's time to give back in the form of defilement on a 2007 KTM Supermoto. I got this bike more or less stock, rode it to both coasts, alternatively abusing and neglecting it for the last few years.

As an intro, here is it's maiden voyage to NYC and part of the way back. Ultimately pavement was met in Ohio or Indiana, but at least we denied state governments of their toll fees a few times along the way. This is shortly before my buddy gets picked up for some BS that results in possession of MJ, I bail him out, and we ride 2up with all gear on a T309 about 90 miles to the airport so I can get back for work in 2 days. Hint: I'm standing on it



As it sits, with no pipes, plastics or tank



Cut off the tail


Quick mock-up of stock tank, seat, and a small tail just to break up the blunt, cut-off look



That's as far as I got tonight. The headlights are Warn spot beams which I hooked up just to have something rideable. I like the dual circle headlight look, but these have a very narrow beam pattern which sucks at night. Have a few ideas about how the tail light and exhaust will look, and would like to shorten the wheelbase as well as lower it an inch or two. Probly also replacing the top triple clamp with something without risers cast in, and maybe trying to powdercoat the clamps, subframe and swingarm. Also probly not going all flat black, some color is nice.

Feel free to criticize

Dan
 

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probly wreck it
Joined
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49 Posts
Discussion Starter · #3 ·
Basically got an D- in motorbikes today...pinched a tube putting a dirt bike tire on, AND scratched the new rim in 3 spots. Tried to patch a different tube, which did not hold air. Also got staples which are too long for recovering the seat on same dirt bike, so that didnt get done either.

Only real (small) progress made was the good ol' Nicky mod on the 950 :). The stock cover has an awkward circular center section molded in that had to be worked around, so the shape isn't as sleek as I would have liked. Maybe will do something out of aluminum at a later date, but at least something productive happened today.
 

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probly wreck it
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49 Posts
Discussion Starter · #5 ·
Oh man. I would bastardize and abuse that thing so hard
This is the plan exactly.

Downdraft FCR39s were test fitted. Apparently the people at Motion Pro never actually installed their cables on the intended carbs, because they dont exactly fit the brackets. Not that I can complain too much, at least a kit of sorts exists. Also had to eBay a throttle housing from a 950 Adventure, since the SM is apparently a stepchild.


Instead of removing and resoldering the cable barrels after threading the cable housings further, I took the easy way out and just cut down the bracket on the rear carb. Front cables fit fine. Probably not the right way to do it, but if the shortened brackets bend, that's what will need to be done.


Seems to fit fine with room for adjustment now.



Next, will be shortening the swingarm. This thing needs a wheelbase shorter than a Super Duke, and a steeper head angle via shorter front suspension stroke will also help. Strictly because it should be a fight to keep the front end down.
 

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probly wreck it
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49 Posts
Discussion Starter · #6 ·
Stock upper triple clamp:


The stock clamp has cast-in risers, which seems wrong on two levels. Being stock isnt one of them. Throw money at it:

The stock switchgear is bulky and super ergonomic, going to steal the switches from my old 900RR.



950s use a linkless rear suspension:


The lower shock mount needs to move forward so the rear wheel can come ~2 inches forward. I'd like to use the stock shock if possible with a new spring. So...lets use a linkage. Here's the linkage from a '94 900RR, which is what I'm going to emulate:


Here's another look at the KTM swinger and lower frame crossmember (black piece):
 

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probly wreck it
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Discussion Starter · #7 ·
Looking at the other aluminum-framed linkage setups in the garage (CR125, CRF450, 900RR), the lower frame crossmember is a beefy, solid-looking piece with large welds to the frame spars. The crossmember from the VF500F is steel (like the KTM), and is similar in cross-sectional diameter, so that's encouraging. Also the KTM and the 500 are similar in weight (410 vs 430 lbs, respectively).
 

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probly wreck it
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Discussion Starter · #8 ·
Turns out suspension linkages are a little more complicated than I can sort out in a few days, not having done anything like this before, so here's what I've found out so far.

Heres another look at the lower frame crossmember. I think the tube's cross-section is thick enough to support the dogbone for the 900RR-style suspension linkage, but I'm not real sure about the ends. Not a lot of weld length there compared to the VF500F, which is the closest thing I've got to compare to. So this will probably get a big gusset to the frame spar on either side, and then two tabs to hook the dogbone to. Near as I can tell, the frame is 4130 chromoly, so that just needs ER70S or ER80S filler to weld it, and shouldnt require any post-heat or special treatment, which is nice. If that doesnt sound right, please let me know.



Random details:

'08 990 SuperDuke rear spring rate: 17 kg/mm
'94 900RR rear spring rate: 15 kg/mm
950 Adventure rear spring rate: 13-16 kg/mm
I would have thought they would be more different, considering the linkage differences. Can probly find used springs in a close rate. Lots of spring rates (4-26 kg/mm) are available aftermarket in this size from RaceTech and probably others, too.


Totally disassembled the 900RR also, so heres my take on the swingarm pivot tool just for fun. Galvy fence post smells like shit when you grind it, which I know now. Sorry, brain



Stuck at work for the next few weeks now. If anyone has any good links to a linkage calculator or similar build, please post up. I'm not going to touch the metal til the dimensions are mostly worked out.
 

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probly wreck it
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Discussion Starter · #10 ·
I want to retain the stock wheel and brake, for one. For two, I figured cutting out the swingarm's center-boxed section would allow alot of flexibility for exhaust routing, an underbrace, and shock/linkage mounts. Also, the shock is offset to the left side of the bike (and I really dont want to relocate the upper shock mount on the frame, its a strange design), so I'd likely be cutting up the replacement swinger to some extent anyway.

But probly most of all I just dont have much experience and tend to do things the hard way through ignorance. What do you see as advantages by changing to a shorter arm?
 
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