Author Topic: Wheel question  (Read 2247 times)

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Offline WBechiom

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Wheel question
« on: December 17, 2012, 07:04:17 PM »
Hi guys. My name is William. I've just started working on a 1974 CB750 Cafe build, and I have a question:

I have a set of wheels from a '78 Suzuki GS750 that I'm quite fond of. I also have the front forks and calipers, and the rear disk and sprocket.

So my question is obvious: would it be possible to rebuild this fork assembly with new uppers in a CB750 triple tree and use it on this build? My gut says that if the spacing is different on the trees (they look pretty close to my eye-ometer) I should be able to address that with correctly sized spacers on the front axle.

The more important question is the back wheel. I can fabricate a mount for a GS750 rear caliper, and again, would it just be a matter of getting the spacing right to make sure the sprockets line up?

Thanks in advance.
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1974 CB750K4 Cafe Project "Sully"
projectsully.tumblr.com

Offline 70CB750

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Re: Wheel question
« Reply #1 on: December 18, 2012, 05:17:55 AM »
That is a nice wheel, well worth the effort.

You need to measure first, the fork tube on CB750 is 35mm diameter (there was 33, but that's so rare we can skip that one).  If your fork is 35mm, you are home free and all you need to find is a CB750 triple tree.
If the tubes are different, you will new parts machined for it.

As far as the rear wheel, again, you need to measure how much space you have.  If the regular swing arm does not fit your wheel, look for a late CB swingarm - for instance 77 CB750F.  They had rear disc brake and the swing arm is 10mm wider than the older K style. 

Good luck - my current project is to mix and match 73K and 78F2 - that's why I know  a bit about those swingarms.

Prokop
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I love it when parts come together.

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CB750K3F - The Red
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Offline swan

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Re: Wheel question
« Reply #2 on: December 18, 2012, 05:19:09 AM »
Cafe racers have spoked wheels.
1975 CB400 F cafes, 1974 CB750 K4 Cafe, 1966/1976 Triumph/ Norton Triton Cafe and 1962 DBD34 BSA Gold Star Clubman.

CB750 build http://forums.sohc4.net/index.php?topic=52551.0

Offline WBechiom

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Re: Wheel question
« Reply #3 on: December 18, 2012, 06:29:33 AM »
That is a nice wheel, well worth the effort.

You need to measure first, the fork tube on CB750 is 35mm diameter (there was 33, but that's so rare we can skip that one).  If your fork is 35mm, you are home free and all you need to find is a CB750 triple tree.
If the tubes are different, you will new parts machined for it.

As far as the rear wheel, again, you need to measure how much space you have.  If the regular swing arm does not fit your wheel, look for a late CB swingarm - for instance 77 CB750F.  They had rear disc brake and the swing arm is 10mm wider than the older K style. 

Good luck - my current project is to mix and match 73K and 78F2 - that's why I know  a bit about those swingarms.

Thanks a ton for the feedback. I think this is going to work out well. The front looks like it's not going to be a problem, and I am going to replace the stock triple trees with a billet set with a built-in brake manifold anyway. Tubes are 35mm, and the calipers and lowers are in great shape. Plus, I won't have to deal with the dual-disk conversion.

You are dead-on with the swingarm issue. With the wheel and axle assembled, my '74 swingarm is a few millimeters too narrow. I'm going to source a '77 swingarm. I'm stoked to find that this is going to work out. I want disks all the way around, and I'm not a fan of spokes, nor am I a traditionalist.

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1974 CB750K4 Cafe Project "Sully"
projectsully.tumblr.com

Offline WBechiom

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Re: Wheel question
« Reply #4 on: December 18, 2012, 06:31:43 AM »
My Cafe racers have spoked wheels.

I fixed your post.
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1974 CB750K4 Cafe Project "Sully"
projectsully.tumblr.com

Offline mono

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Re: Wheel question
« Reply #5 on: December 18, 2012, 07:49:42 AM »
My Cafe racers have spoked wheels.

I fixed your post.

HAHAHAHAHA!!! :)  well played.

+1.

** I really like those wheels myself.  I hope you can make it work.  I love spokes, but i *hate* cleaning/polishing spoked rims.
« Last Edit: December 18, 2012, 07:52:41 AM by mono »

Offline KRONUS0100

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Re: Wheel question
« Reply #6 on: December 18, 2012, 11:22:00 AM »
can be done.  just about finished with installing kz750 wheels onto my 76 750F.  spacing is important.  im lucky in regards to front brakes fitting the kz rotors nicely and that i already have a DOHC swingarm from a 81 750f installed
MATT
current bikes:  1976 CB750F, 1981 GS1100E
bikes owned:1981 GL1100I, 1990 GS500E, 1981 GS850, 1977 and 1979 GS750, 1974 CB750, 1975 CB750, and a 1982 GS750E

Offline WBechiom

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Re: Wheel question
« Reply #7 on: December 20, 2012, 09:04:26 AM »
I've got a '78 swingarm on the way. The hardest part was finding those stupid little chain adjuster stops. I paid almost as much for them as I did for a swingarm.

I'll have a roller before too long.

:)
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1974 CB750K4 Cafe Project "Sully"
projectsully.tumblr.com

Offline WBechiom

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Re: Wheel question
« Reply #8 on: December 21, 2012, 06:16:26 PM »
Alright. I know when I'm beat. I initially thought the fork tubes were the same size. They are not. I'm going to sell the wheels and just go with CB750 spokes. I don't feel like trying to sort out what I'd need to make it work. Anyone have a good, comprehensive guide to the front dual-disk conversion?
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1974 CB750K4 Cafe Project "Sully"
projectsully.tumblr.com

Offline 70CB750

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Re: Wheel question
« Reply #9 on: December 22, 2012, 04:30:52 AM »
Bummer :( man!  What is the tube diameter?  Do you have the tripple tree that goes with it?
Prokop
_______________
Pure Gas - find ethanol free gas station near you

I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline Geeto67

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Re: Wheel question
« Reply #10 on: December 22, 2012, 05:04:48 AM »
What's the axle diameter? IIRC it should be the same for the cb750 and GS. I know it is the same for a water buffalo and there is a year where Water buffalo and GS parts cross over.

My point is, it may be possible to run the wheel with a cb750 fork setup and all you have to make are spacers and adaptor plates for the brakes.
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Offline Geeto67

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Re: Wheel question
« Reply #11 on: December 22, 2012, 05:06:27 AM »
Also, since the GS rotor is a 6 bolt, try seeing if the 74 cb 750 rotor will bolt to it.



BTW, you give up way too easy.
Maintenance Matters Most

Offline Xnavylfr

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Re: Wheel question
« Reply #12 on: December 22, 2012, 05:10:32 AM »
If you want a single front brake, you can either just remove one rotor and get the lines from a K model (single hose) from master cyl to the caliper or get a set of forks from a K model including  , wheel/rotor/caliper/ proportion valve.

Easy change over!


Xnavylfr(CHUCK)