35mm Fork Compatibility

o1marc

Over 1,000 Posts
I want dual discs on the sand cast. I will have the Kimtabs and want something better than the stock CB750 caliper. Since I probably have to custom make bearing carriers and adapt the stock CB speedo drive I figured it would be just as easy to swap another bikes forks into the 35mm trees. What bike had 35mm forks and awesome braking calipers? I would prefer multi pot and fixed caliper would be okay. I guess rotor diameter is important also. I suppose I could machine a dual bolt pattern into the bearing carrier, one set to mount the disc to the wheel and then a set to mount the rotor to the carrier if the rotor were a different diameter than the stockers. All of this is an attempt to use lighter parts up front.
 
82 gl500 interstate had dual piston calipers is a 35mm but you will need to trim the length on the fork tubes
 
Why stick with 35mm forks?
Gl1000 will bolt on.
It's lighter, 37mm and dual disk.

Can't think of much that has racing calipers.
The Honda twin piston calipers from the latter bikes let you run some nice pads.
I have a write up on caferacer.net and sohc4 about the swap. Can talk to you about some other swaps too.

Don't put the early cb750 calipers down though.
Harley used them on the factory race bikes for a while, so they can't be that bad.
 
Early 90's GSXR, ZRX1200, or GSF1200 "Bandit" all have traditional forks with big stanchions and big brakes.
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Surffly, I want to keep the stock trees and gauge cluster. Easiest way is to just stick different forks in them.
I checked the member list at CR.net and don't see your name, so can't check the reference you mention. Do you use a different name there?
 
http://hondachopper.yuku.com/topic/2755#.Viwgdn4zbng

rz350 forks are pretty popular with the flattrackers,ex500 early is 35 only issue is they ran single rotor,you would need 2 left legs but hell you can stop plenty good with a well sorted single disc lashup unless you ride like a maniac
the other thing to look for is its worth it to use some modern enough that they have du bushings ,top and bottom,not just a naked leg in a slider you can even dial in the bushings by shimming them it was a mod that i did to mine and a few other kdx200 forks and it was a vast improvement,in fork action/compliance,set up with minimal clearance vs from new, when they were stiction plauged sloppy sliders even with the stock du bushings
 
XS650's had 35mm forks and both lowers had mounting holes for brake calipers and are reversible (calipers behind legs). I know you said you wanted to stick with stock size, but if you go with 37mm, you open your options up to basically every sport bike from the 80's and early 90's. I'm swapping a CBR600F front end onto my TX500 right now. Granted I have to make a new stem, but conversion bearings are available, I'm going from 34 to 37mm, and can use the CBR 4 piston calipers with my original rotor and gained anti-dive.
 
surffly said:
I am jaguar on CR and sohc.
How did I not know that? ::)
Jewbacca, I did a CBR600F fork/wheel swap on my CB400f along with a a highly modified rear wheel. i can steal it when the time comes if I still own that unfinished project. But then it's gauges and clip ons, headlights, etc to finish it off. trying to stay in my budget which is not a shoestring budget, but just the plastic ends of the shoelace. ;D
 
Pretty sure he means the VTR, since he mentioned the "normal disc". Before 89 the VTR had an inboard disc. However, on the 89 with the external disc, it was only a single, and I am pretty sure the forks that year went up in size.
 
I would say based on what you are trying to achieve, the xs650 forks are a perfect candidate......because the legs both have mounting tabs which are centered in the leg so both can face rear-ward. now, there's also some adapter brackets available for the xs650's now to mount up newer brembo calipers and rotors. I think pandemonium choppers is one of the places offering this. Mikesxs.net sells cartridge emulators and it's easy to source progressive fork springs. I think all of that combined will get you what you're trying to achieve in performance wiithout losing your factory triples'controls, all while bringing modern tech and appearance to the front end. Also, the early honda 6-bolt rotor pattern is the same as the xs650, so the spacer and rotor setup would work with your stock wheel and speedo/axle.

;)

that said, I have two sets of xs650 forks, one is absolutely mint shape perfect for this....I'd sell 'em for $100 plus the ride.

I have two front xs650 rotors too if those are of interest....the kit is $60 from pandemonium, just have to source calipers.

pandemonium kit:

http://www.pandemoniumc2.com/#!parts-store/cmai/!/Pandemonium-Brake-Kit-TM-35mm-&-34MM-for-XS650/p/46227518/category=11951480

the brembo goldline calipers are found on the following models (in case you want to source a pair on ebay)

Ducati models:
ST4 2000 to 2003
ST4S 2002 to 2004
ST3 2004
748 1999
748S 2000 to 2002
748R 2000
996 1999 to2001
996S 1999 to 2001
996SPS 1999 to 2000
998 2002
998 matrix 2004

also, yamaha yzf600 rotors are the same diamater as stock xs650, and same bolt pattern. I forget if offset is the same but I can check tonight when I get to my shop. I have yzf rotors too but they aren't for sale :)
 
Good info Focus. I won't be running the stock wheels, Kimtabs are on it. I need to fab a custom bearing carrier to accept the stock speedo drive. Looked at the Pandemonium kit, could fab up my own. Like the idea of Brembo's.
 
yeah the kit is simple....I'd fab my own as well but never know what level of fabricator I'm responding to so gotta start at square one for a reply ;)

if the kimtabs have the same rotor pattern and distance between mounting faces, it's all the same anyhow.....I haven't run the combo I described yet, I've used each of the parts for different things though so I'm familiar with all of it. I most recently used a stock xs650 19" spoked front wheel with a yzf600 rotor on a suzuki marauder inverted front end. needed to gain 18mm to get the rotor matched to the caliper, and make two small spacers around 8-9mm (memory foggy on this bit) to center the wheel. stock marauder axle is same dia as xs650 so I didn't have to lose speedo, and stem is same as xs650 so didn't have to hunt down conversion bearings either. Ended up grabbing a 10mm rotor spacer from Motolana because at $36 it was cheaper than buying the puck of aluminum to turn my own. made a simple 8mm caliper spacer and bob's-your-uncle.
 
of course if you want period correct that is same as what was used on dick mann's bike at daytona that would be SL350 k1 - on forks XL250/350 are very similar
 
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