racerdave
^ Gone not forgotten ^
The Kawasaki KZ750 twin of the later 70's had a disc/wire rear hub. Lot's of Harley's. All will require custom fabbing.
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timmyc
XS650 Member
Thx for your input. I did find a hub, swing arm etc from a 77 Suzuki GS750 at a salvage yard here in Michigan. As you said it will require some mods but I think it will work well.
brady
XS650 Addict
looking to do a hydraulic clutch, do you think the slave off a 99-03 rsv will work?
usfs68
XS650 Enthusiast
osteoderm
out of the box
That's a mad mad project to be sure... and I fully endorse it!
usfs68
XS650 Enthusiast
You are a bad man Osterderm
osteoderm
out of the box
Since I finally have the Honda running reliably, I've been able to take a little time to get back to work on some misc. XS projects... First up is the rear wheel. Just to re-cap, here is the (thus far) current set-up:
The hub is a stock XS650 front, with Omar's conversion adapter on the the drive-side and my own Aprillia/Brembo brake adapter dealie on the brake side.
Here is the new hub assembly hanging on the axle:
To make the new assembly fit, I need to make up new outboard bearing spacers on both sides, and modify the brake hanger. The new hub is 5/8" wider between the flanges; this makes for a better spoke angle (theoretically stiffer wheel) and puts the bearings further outboard. Also, with the Omar's kit, the stock front bearings are poorly-spec'd... The front hub uses a smaller bearing on the left side to make room for the speedo drive; the Omar's kit flips the hub so the small bearing is on the right/brake side, then stacks an additional large(r) bearing on the drive side. In my new assembly, I've bored out both sides for larger rear bearings. I kept the left side of the hub on the left, because now the cush-drive sprocket-carrier sits into the recess where the speedo drive used to sit. Clear as mud, right?
I made the entire cush-drive assembly 5/16" narrower than the Omar's spacer, so the chainline relative to the hub center would be consistent. The new drive-side outboard spacer is just a simple spool. I hung the hub on the centerline, checked the chain for parallel to the the centerline, and measured the spacer length in place... cut the spool a touch long, then fit, file, sand. fit, file, etc. until the chainline is perfect.
I'd like to replace the straight spool with a a tapered/stepped one that presents more surface area to swingarm and leaves less of a gap where it enters the sprocket carrier, but it'll do.
The brake side is trickier. Unlike the drive side, I couldn't simply make the brake assembly 5/16" narrower to accommodate the 5/8" widening of the hub center; the rotor needs to stay a minimum distance away from the spoke flange to maintain spoke-to-caliper clearance. Also, the outboard spacer I made to fit the Aprillia brake is a beast; stepped with three different outside diameters to center the caliper hanger, clamp the inner bearing race, and clamp the whole assembly. Ultimately, the whole brake assembly needed to move over, with the caliper bracket being clearance to fit the swingarm better. Since the wheel bearing has also moved outboard relative to the brake, spacer material needs to be removed from both sides of the caliper bracket...
In the end, I removed 5/16" outboard and 3/8" inboard... the bearing is now 15/16" further outboard, the rotor-to-hanger clearance is unchanged, and the caliper is 5/16" further outboard.
The trick is to keep the rotor centered in the caliper, 'cause there's really no wiggle-room...
Ideally, I'd like to shave .030" off the inside face of the caliper mounting tabs to get the caliper a smidge inboard... The Brembo caliper supports the pad very well, but leaves just enough slot for the rotor to ride in!
The hub is a stock XS650 front, with Omar's conversion adapter on the the drive-side and my own Aprillia/Brembo brake adapter dealie on the brake side.
Here is the new hub assembly hanging on the axle:
To make the new assembly fit, I need to make up new outboard bearing spacers on both sides, and modify the brake hanger. The new hub is 5/8" wider between the flanges; this makes for a better spoke angle (theoretically stiffer wheel) and puts the bearings further outboard. Also, with the Omar's kit, the stock front bearings are poorly-spec'd... The front hub uses a smaller bearing on the left side to make room for the speedo drive; the Omar's kit flips the hub so the small bearing is on the right/brake side, then stacks an additional large(r) bearing on the drive side. In my new assembly, I've bored out both sides for larger rear bearings. I kept the left side of the hub on the left, because now the cush-drive sprocket-carrier sits into the recess where the speedo drive used to sit. Clear as mud, right?
I made the entire cush-drive assembly 5/16" narrower than the Omar's spacer, so the chainline relative to the hub center would be consistent. The new drive-side outboard spacer is just a simple spool. I hung the hub on the centerline, checked the chain for parallel to the the centerline, and measured the spacer length in place... cut the spool a touch long, then fit, file, sand. fit, file, etc. until the chainline is perfect.
I'd like to replace the straight spool with a a tapered/stepped one that presents more surface area to swingarm and leaves less of a gap where it enters the sprocket carrier, but it'll do.
The brake side is trickier. Unlike the drive side, I couldn't simply make the brake assembly 5/16" narrower to accommodate the 5/8" widening of the hub center; the rotor needs to stay a minimum distance away from the spoke flange to maintain spoke-to-caliper clearance. Also, the outboard spacer I made to fit the Aprillia brake is a beast; stepped with three different outside diameters to center the caliper hanger, clamp the inner bearing race, and clamp the whole assembly. Ultimately, the whole brake assembly needed to move over, with the caliper bracket being clearance to fit the swingarm better. Since the wheel bearing has also moved outboard relative to the brake, spacer material needs to be removed from both sides of the caliper bracket...
In the end, I removed 5/16" outboard and 3/8" inboard... the bearing is now 15/16" further outboard, the rotor-to-hanger clearance is unchanged, and the caliper is 5/16" further outboard.
The trick is to keep the rotor centered in the caliper, 'cause there's really no wiggle-room...
Ideally, I'd like to shave .030" off the inside face of the caliper mounting tabs to get the caliper a smidge inboard... The Brembo caliper supports the pad very well, but leaves just enough slot for the rotor to ride in!
Last edited:
Ivan DeSlayer
XS650 Enthusiast
I actually came here looking for a price on what to sell my XS for and this thread convinced me to keep it and have at it when I get time. Thanks guys.
racerdave
^ Gone not forgotten ^
Derm's work has always been good to watch.
Hi osteoderm,
While this is an old thread now, I've been going through your clutch conversion and am going to go down the same route. I wondered how you found the Aprilia Brembo master cylinder and whether it was a good match to the slave cylinder in so far as getting a good pressure plate travel. I've gone through all 32 pages of your thread, with great interest in your build, but haven't found anything to say if the MC was a good choice. At £130 GBP on Ebay I would like to get it right first time if possible. Can you let me know how you got on? Or if anyone else has done the same conversion with the Aprilia slave, what MC worked for them?
I'm wanting to convert my XS650 custom street scrambler (with 270 rephased crank and Mikes XS 750 big bore kit) with standard clutch arrangement, but using the early R1 kevlar race clutch plates to overcome the clutch slip (which work great).
While this is an old thread now, I've been going through your clutch conversion and am going to go down the same route. I wondered how you found the Aprilia Brembo master cylinder and whether it was a good match to the slave cylinder in so far as getting a good pressure plate travel. I've gone through all 32 pages of your thread, with great interest in your build, but haven't found anything to say if the MC was a good choice. At £130 GBP on Ebay I would like to get it right first time if possible. Can you let me know how you got on? Or if anyone else has done the same conversion with the Aprilia slave, what MC worked for them?
I'm wanting to convert my XS650 custom street scrambler (with 270 rephased crank and Mikes XS 750 big bore kit) with standard clutch arrangement, but using the early R1 kevlar race clutch plates to overcome the clutch slip (which work great).
