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XL Cush hub on an XR600R, Heres how

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Sorry disc brake guys, this ones not for you.

My 87 Xr600r was in dire need of rear brakes and wheel bearings, add that to the fact that its going supermoto soon and the obvious next step is swapping in a cush drive rear hub. I'm not afraid to spend money when necessary but the $600 for a Rad cush hub was just more than i could see myself spending on a part that honda used to include for free on an xl600r.

I happened to have a complete rear wheel off of an 83 xl600r laying in the parts pile complete with new brakes and bearings. So out came the measuring tape and a lot of pabst blue ribbon.

The obvious issue is that the cush hub is about 13/16 of an inch too wide to fit in the xr's aluminum swingarm. But the aluminum swinger is lighter and about a 1.5 inches longer that the steel xl swinger, both are qualities i'm in favor of on this bike. So, rather than swap the whole swingarm and wheel together, I was determined to make it work or destroy the wheel trying.

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For the left side of the wheel, a custom spacer is necessary. I have a friend that owns a shop that restores vintage brits and has a lathe so he used the stock "top hat" style spacer as a template and made one 0.720 inches long and it worked great.

This side is extremely tight. Your hub will end up about a hair width from the swingarm.

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Edited by Backwoods Bomber

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On the right side the "nose" on the brake plate needs to be trimmed 3/8 of an inch. This could be done with a saw or grinder but i had my buddy throw it on the mill for a perfect cut.

You will reuse the stock little washer with the three tabs that bend in to retain it.

The pic shows the trimmed brake plate without the washer to show the cut made.

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Now the whole works will fit in the swing arm (kind of) and you will start to see the next issue, chain alignment.

I simply put a set of factory honda sprocket washers between the sprocket and hub to space the sprocket over to the left a little and the chain ended up very straight.

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Now that your sprockets line up you will notice that the wheel will not slide forward into the swingarm. The xl hub is much larger and the brakes are also. The stock xl brake arm on the hub will not clear the swing arm.

This is a two part fix, step one is to swap the steel xl arm for the lower profile aluminum one off the xr wheel. The xl one uses a nut and bolt and the nut protrudes forward and would limit chain adjustibility. The xr arm is internally threaded and doesent use a nut so it leaves more room on the front.

The second step is to trim off the steel tang on the back of the swing arm that is used to rest the axle on during wheel installation. I used a cut off wheel on an angle grinder.

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So, i thought i was done...... but the wheel wouldnt turn after i tightened the axle nut! F$#k what now? Then i realized that due to the narrower swingarm, the little post on the swingarm that the brake plate slides on during chain adjustment was just slightly pressing on the brake plate and twisting the whole thing inward. After removing about 1/8 of an inch from the post, all was golden!

All said and done, i think most guys could pull this mod off really cheap if they find a donor wheel, maybe $100 worth of simple machining tops. And all of the other parts come off the stock bikes.

So far, I love it! It rides much smoother and the larger diameter brakes make a huge difference. If anyone decides to go for it, throw any questions up here and im happy to help if i can.

Scott

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Just an FYI next time you need a rear sprocket, there are offset sprockets available. You may be able to find one that fits the XL hub with the correct offset.

 

I'd be a little concerned with spacing the sprocket out because it's not got the same support from the hub lip and is relying on the bolts more. The original method has the bolts tightening the sprocket flush against the hub (sprocket carrier in the XL's case).

 

Thanks for the information. I could even use that to swap an aluminum swingarm onto my XL.

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Just an FYI next time you need a rear sprocket, there are offset sprockets available. You may be able to find one that fits the XL hub with the correct offset.

 

I'd be a little concerned with spacing the sprocket out because it's not got the same support from the hub lip and is relying on the bolts more. The original method has the bolts tightening the sprocket flush against the hub (sprocket carrier in the XL's case).

 

Thanks for the information. I could even use that to swap an aluminum swingarm onto my XL.

That's good news, I didn't know those were available. What company makes them? I'm planning on changing gearing soon anyway. I will be watching the bolts/sprocket carrier very close in the mean time. I actually used the xr sprocket, it is the same bolt pattern and hub diameter as the Xl.

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Good job Bomber..I'll just add this..That part that the wheel sits on that you chopped the end off can actually be removed from each

side of the swingarm. If you look inside the swinger where the wheel sits you'll see that those 2 metal plates are screwed onto

the inside of the swingarm with a couple of little countersunk/recessed screws..If you remove the screws the plates drop off and you gain a couple

more mm each side for the wheel..I've been running my cush wheel in the XR swingarm with them removed for months..No issues to

report on that part..

Edited by Horri

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I'm glad to hear those plates arent necessary, i was concerned that the aluminum swingarm would be too soft and get boogered up without the protection of the steel plates. Its good to know that the swingarm is tougher than i thought.

Im just looking forward to getting this bike road legal so i can put more miles on it, its always been a really fun bike but i ride my others more now a days because i can just ride them to the trails.

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I dont know exactly what wheel I used, (probably twinshock XR250?)except I was able to use the XR600 brakeplate in the new wheels hub, which meant it didn't need any cutting on the brake side.

  The sprocket lined up perfectly, but the collar on the chain side is only about 8mm long. 

Most of the old honda wheel hubs seem to have similar dimensions, overall width/sprok/brake/axle size etc, so by mixing and matching bits they seem to fit.

    Cush hub makes a big improvement on the road with less chain chatter, compression lock ups etc. Well worth the effort.

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