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Discussion Starter #1
I want to put a dual disc conversion on my 750 and convert the rear to disc if possible. I have a 1980 HONDA CB750 F I can get my hands on, its just in MO(have to pick it up). I would figure swing arm would be different.
If so what all interchanges between the later f models and the K's.

My question is what would I need to do to make it work?

If at the least I would like to be able to put the comstar wheels on mine with a drum in the back. And dual disk in the front. But I would rather a disc in the back.

Would there be problems like
chain alignment?
Wheel spacing?
Fork dia. ?

Scooters are like fat chicks, a whole lota fun till ur friends find out.
 

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Just peeking in for a minute..will have a more full answer tomorrow.

What year 750 do you have?

The general rule is that you cannot interchange DOHC and SOHC parts (although there are exceptions).

There are other ways to get a dual disc for a SOHC cb750

75-77 wire wheel GL1000 front end conversion is one of them.
 

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Ok,

So here are the options for a SOHC 69-76 K or F bike:

1) Convert your existing setup. The hard part here is figuring out the speedo drive. The old way was to get K0 parts but since they are hard to come by these days you will have to modify your existing setup or test fit cb550 parts till they fit (I know there is at least one year that works but I don't know what year - perhaps 74?).

some links:
http://www.sohc4.us/forums/index.php?topic=2582.msg171561#msg171561

www.sohc4.us

2) Get a 1975-1977 GL1000 Goldwing front end. You will need everything from the triple trees to the brakes. This is a bolt on but you are on your own as to how to mount the gauges.

AS for DOHC parts on SOHC bikes. You can use the DOHC F swingarm, but you will need to cut down the pivot point to fit (not hard, just take careful measurements). The front end I do not think is a bolt on but the later 77-78 SOHC F's used a similar front end that is a bolt on (provided you get the trees). I am not sure about the chain line, but I think if you use a 1979 wheel it may not be a problem.

All the F bikes are rear disc. YOu can get a comstar with drum for the rear but it will have to come from a K or C and it will likely be 16".

The easiest way I can think of for putting a rear Disc on an early K bike is to get a 1975-76 F rear end (the whole thing, swingarm to rim). It will be a spoked rim and it will bolt into your frame. The only mod you will have to do is make a mount for the master cylinder for the rear brake.

Personally, if I were you I would look for a 1975-77 GL1000 (with spoked rims the comstar won't work) do get you dual disc up front and keep your drum in the rear. Honda discs from this era were succeptible to decreased braking in the rain and the drum doesn't have those problems. If you must have a rear disc then look for the 75-76 F to snatch a setup from.

IF you really really want comstars I would look for a 1977-78 F rolling chassis in your area and just strip the front and rear to work on your bike. Be warned the 1977-78 front end pieces are not interchangible with the earlier pieces you will need the trees to convert. The same goes in the rear. The general rule is that if it has comstars then it won't work with spokes. Once you have the comstars if you want better brakes you can upgrade to the 1982 2 piston calipers on the cb750F and 900F
 

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quote:
this is another board i belong to http://www.salocal.com/sohc/tech/dual_disks/dual_disks.htm

some people are like slinkies, basically useless but they still make me smile when i push them down the stairs
If it is like he says then the speedo drive from a 1971-to 1973 cb500 four or 1974 cb550 should work. You could also svae weight by making a spacer and using one of those fancy digital bike speedometers which are tons more accurate than honda ever was.
 

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Beware that the 77 GL front end is not a bolt-in. The 75-76 are. I got a 77 Gl frontend form a guy and had to press in my 75 CB steering stem. Otherwise it went right on. Jimmy
 

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Discussion Starter #10
Thank all of you very much. You are very helpful. I think i will go with the goldwing conv. Not worried bout the gauges cause, those are going in the air tech fairing that came in today. I will post picture when i am all done.

Another thing i am bout to order th ecletronic ignition from Dyna anybody heard anythig good or bad bout it?

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I think the GL conversion is better for lots of reasons, including the snazzy aluminum rim, and the better calipers. Those floating calipers with the arm used on early CBs suck.
 

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dyna S ingition is really good. Works similar to your points but maintenance free. If you can afford it though the Dyna 2000 is the best setup, multiple ignition maps and doesn't depend on the cb parts that will wear out.

77 GL1000s with comstar rims are not compatible. Some of the early 77 GL1000s were carry overs from 76 and had spoke wheels.

Edited by - Geeto67 on Jan 07 2007 2:26:10 PM
 

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Discussion Starter #15
I also have a 1983 CB 1100F. Would that front end work on my cb 750?
( Cb 1100 Motors messed up with no seat, tank , or body work.)

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hey rider.............where are you at? i'd buy the carcass of that 1100f if you were nearby me (columbia sc)

some people are like slinkies, basically useless but they still make me smile when i push them down the stairs
 

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quote:
I also have a 1983 CB 1100F. Would that front end work on my cb 750?
( Cb 1100 Motors messed up with no seat, tank , or body work.)

Scooters are like fat chicks, a whole lota fun till ur friends find out.
Short answer is no, the long answer is probably not but if you get a SOHC 77-78 SS front end you should be able to use the brakes and front wheel with some minor mods.

1100F forks are 37mm. the 75-76 GL1000 forks are also 37mm, I wonder if there is any way you can use the GL1000 trees to mate the cb1100f forks to the SOHC cb750. If you send me measurements of the cb1100f fork spacing I can measure my GL front end and see if they are close.
 

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Discussion Starter #18
I am in the dfw area. But if you are looking 4 parts i am gonna sell everything I don't use 4 the conversion.
If you would mesure that Gl1000 front end the spec off that Cb1100f front end are. 6" inside tube to inside tube. And 7 9/16" center to center. Any advise would help.

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Discussion Starter #19
Hey Geeto can you measure your Gl1000 front in for me. It would be a big help. As i can't currently find a set of clamps to test fit the forks with. Thanks

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quote:
Hey Geeto can you measure your Gl1000 front in for me. It would be a big help. As i can't currently find a set of clamps to test fit the forks with. Thanks

Scooters are like fat chicks, a whole lota fun till ur friends find out.
sorry...things got a little busy with the CW motorcycle show in town and I spaced. I'll measure it today.
 
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