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I am replacing the seals and painting my forks on my 73' CB750. And there is some funny business going on. Previous owner changed a bunch of stuff up and i think the forks on the bike are not stock.

Here are the forks that came off the bike:

They look to me to maybe be setup for dual disc. As compared to an extra set of forks that PO gave me when i got it, these are both right side legs:

I purchased seals online for 73' CB750 and they look like this and have a metal spring/ring inside:


Similar to the ones in the extra set of forks i have:

The seals that came out of the forks on the bike (the black ones) look like this, w/ no metal ring inside:


Also the black forks DO NOT have a rod attached to the top bolt inside the springs like the extra forks do:

So anybody know what is going on here. If so what model and year CB did the black forks come from, so i can buy appropriate seals, or will the new seals i got work w/ them, maybe?

Any help greatly appreciated.

Edited by - kawiracer on Sep 28 2007 10:04:08 PM

Edited by - kawiracer on Sep 28 2007 10:07:16 PM
 

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it looks like all the stuff that i have for my cb350g from 1973.
seals should be 32mm and the rod style guts go up to 73 or 74.so
forks by frank said when i got new ones from them.

Eric750
 

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You have cb750 forks off a '73 or '74. All cb750 fork legs come setup for dual disc although the only one to come from the factory with it was the CR750.If you have a set of forks without the dual disc lugs they are not 750 forks, (they could be cb500 forks or early 74 550 forks).

The seal on your 750 had been changed for a leak proof seal a while back. The seals you have are more of a stock type setup.

Other than that it's all good.
 

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Discussion Starter #4
awesome, i didnt know all the 750s came setup for dual disc.

should i get different or better seals?
 

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The one piece that the cb750s did not come setup for with dual disc is the K0 flat speedo drive which is something you need if you are going to run Dual discs and a cable speedo. It is not an overly hard part to fabricate but to get a factory piece is bordering on unobtanium.

Other than that it is just a matter of reversing the caliper and getting another disc caliper mount. Oh and longer disc bolts too (grade 8 or better).
 

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I've heard that a cb500/550 speedo drive will work. Don't know if it's true.
 

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quote:
I've heard that a cb500/550 speedo drive will work. Don't know if it's true.
I heard that too, and probably have helped spread that rumor also, but I fear it may not be true. There was someone on the SOHC board who said he used a 71 cb500 speedo drive an that it was identical to the K0 drive. What it turned out to be is that he bought a k0 drive off ebay that had been mislabeled as a cb500 drive and was able to set up his bike as dual disc.

To tell you the truth, those bike speedos with the magnetic trigger are much lighter and more accurate than the original 30+ year old honda junk. plus they make your bike more racy.
 

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Ok, so if all cb750s have "dal disc" forks, why bother with the entire gl1000 front end swap? Wouldn't it be easier to just stick the front wheel onto your cb750 forks?
 

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quote:
Ok, so if all cb750s have "dal disc" forks, why bother with the entire gl1000 front end swap? Wouldn't it be easier to just stick the front wheel onto your cb750 forks?
Ok:

1) the GL forks are 38mm not 35mm like the stock cb forks. They are also almost an inch longer. This allows cafe guy to run their clipons on top of the tree and chopper guys to get longer forks cheap. Also the trees for the GL1000 are beefier, their stance is wider, and have a little bit more handlebar raise which makes it easier to run...ick...clubmans.

2) The GL wheel is alloy. Not many people realize this and while cb750A rims have gone up in price the GL1000s can still be had semi-cheaply which leads me to #3...

3) the brakes are better. The 75-76 gl1000 calipers are huge single pots, and work much better than stock cb750 single pots. The braking systems between the two bikes are completely different and you cannot mix GL1000 discs with cb750 calipers and vice versa. The wheels however are pretty similar and if you use your cb750 discs on cb750 calipers on a gl1000 wheel you can have an alloy wheel, but you must also use the cb750 speedo drive as the gl1000 speedo drive will not work with the cb750 discs. However if you absolutley have to have a cable speedo this is the way to get dual discs and keep your stocker speedo.

as a final note because of the geometry of the GL1000 front end, the little wiggle cb750s get at speed and when decelerating is pretty much eliminated.
 

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for what its worth...

that is the right fork from my '72 cb750

that is the right fork from my '76 cb750

'72 left fork

'76 left fork

i've heard people say that you would need to use a cb550 fork for a dual brake setup on some cb750's. is there any merit to this? obviously, i'm not the original owner of either bike so i can't say they are for sure original forks.

'72 cb750
'76 cb550
'76 cb750
 

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There are "early" and "late" forks on cb750s.

Early forks run from 1969 to 1972, the late forks run from 1973-1978 on the K bikes and 1975-76 for the F bikes.

You can't mix early forks and late fork brake pieces and vice versa. Really all you are doing is is setting up the same brake system on the other side of the wheel and reversing the caliper on the mount. I don't think the calipers are any different just the mounts that attach them to the fork.

I have heard about the 550 fork thing too, and frankly I don't think it is necessary (but I could be wrong). I just never have done it.
 

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quote:
quote:
Ok, so if all cb750s have "dal disc" forks, why bother with the entire gl1000 front end swap? Wouldn't it be easier to just stick the front wheel onto your cb750 forks?
Ok:

1) the GL forks are 38mm not 35mm like the stock cb forks.
Ahem:), the GL forks are 37mm. I like the GL forks for the CB 750.

I've heard the CB 500 calipers on the CB 750 for dual discs. I think its really not needed as you would need to get 2 X CB 500 Calipers and 2 discs and it would probably be easier to just get 1 X CB 750 Caliper and disc. The 500/550 discs are smaller in diameter and I think the larger 750 discs look more "appropriate". The stock speedo drive plate can be modified to work with the dual discs.
DG
 

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I am putting them on an H1 Kawasaki, but I do have a set of cbr f2 forks that I setup for a CB750. Missing the cbr front wheel and brakes which is why I haven't done it yet.
 
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