Yamaha XS650 16" to 19" rear wheel conversion

johnnyc14

Active User
H-M Supporter Gold Member
Joined
Feb 17, 2013
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336
I am starting a new winter project and picked up a very tired 78 XS650 special as the base for it. I'm going the 19" rear wheel route so I bought a 19" front wheel from another Yamaha. I measured the dimensions of the original 16" wheel and used them for dimensions to machine some spacers so the sprocket and brake rotor would be in the stock location in the swingarm when the wheel is centered. I bought a sprocket blank and machined the center hole and bolt hole locations to match the original brake rotor mounting surface on one side of the wheel. I bought a 4.5" chunk of aluminum from the chop bin at the local metal supplier and turned a portion of it to 4.100 which will be the finished OD of the spacers.

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Then I cut those slabs off in my band saw and trued them up on the lathe.

This is the brake rotor side.

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I used 12mm dowel pins inserted in the teeth of the sprocket so I could mount it on center in the lathe and super spacer chucks. That worked very well.

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Here's the sprocket I made next to the factory one. I used gunsmith's cold blue to cover the exposed steel area after machining.

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Here is the sprockert side spacer. I machined a pocket for an extra wheel bearing in the sprocket holder to help deal with the extra load on that side of the wheel.

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I machined a spacer to go between the two wheel bearings and another to go between the sprocket holder bearing and the left wheel bearing. I heated the sprocket holder up to 175 degrees with my heat gun and the bearing dropped right in

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Here's the assembled wheel ready to be mocked up in the swing arm.

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I clamped a lenght of 1/2" square aluminum shaft to the front sprocket to align the rear sprocket and measured and machined the outer bearing spacers from stainless.

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I mounted the front wheel on the forks and shecked the wheel alignment with 2 lengths of straight lumber and it turned out spot on.

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Now that this part is done I will strip the entire bike down for re-build.

John

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Hey, Johnnyc14!
This is TwoManyXS1Bs from the 'other' forum.
Joined-up here not long ago. There's several others of us on here, too.
Your project is really lookin' good!
 
Hey, Johnnyc14!
This is TwoManyXS1Bs from the 'other' forum.
Joined-up here not long ago. There's several others of us on here, too.
Your project is really lookin' good!

Fantastic job! Love it! Please keep us updated. I love a good bike build!
 
Thanks guys, old motorcycles and machine work go together like peas and carrots. It's cool to be able to make your own parts for this old stuff we work on. Steve, I like your clutch pushrods idea, I'll be making one of those at some point.
 
Very cool, I love watching builds like these, please do post more as you go along. Aluminum is so fun to machine.
 
The used 19 inch wheel I bought came with 2 slotted 300mm front brake rotors. The original single front 300mm rotor and the rear 270mm rotor are not slotted. I plan to use dual front brake rotors and they will be the slotted ones so I decided to match the slot pattern from the front rotors on the rear one. I mocked up the first slot and spot drilled the center and both ends of the slot to get locations on the DRO. With the rotor mounted in an extra hub I made and in my Vertex super spacer I copied the location at 60 degree spacing around the rotor and drilled all the holes to 8mm the slotted them with a 1/4" end mill. The stainless rotors are pretty hard so it was slow going but turned out well. After the slotting I mounted it in the lathe and use 320 grit sand paper to polish it up a bit.

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John

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Very interesting reading,I have an XS650 I plan to convert to 19 inch rear wheel was going to do the machining at place of work but I no longer work and am without a lathe at moment.I was going to buy the conversion kit from Omars but will see if situation changes for me soon
 
Very nicely done Johnny. Sorry I missed this thread earlier.

The true level of workmanship in my opinion is to make it look like it rolled off the assembly line like that and not look like an afterthought. I think you nailed it.

Great job.
 
Thanks Mike. The Yamaha project has been put on hold for a while so I can get some other things done. I will get back to it soon.

John
 
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