Topic: 82' CB900F to 78'CB750K?

[zeus87]

Found a nice 1982 CB900f parts bike cheap.  I'm wondering if anyone has done the front end conversion (fitted to a 78' CB750K)?  I already have single disk comstars, but would like to convert to dual.  Is this just a matter of swapping parts or is fabrication a must?  Also the rear shocks look to be in great condition, will they replace my existing factory shocks and if so what will they do to the ride height.  Thanks alot everyone

[Geeto67]

1982 900F forks are 37mm and won;t work in stock cb750 triple trees. The good news is that the brakes are really great. I think the DOHC F neck stem is longer and that is why the trees won't fit on the SOHC frame (i can't verify it because my 900F is currently together). You really don't want the cb900f triple anyway because it has the fuse box in the top of the clamp held closed with screws.

However, if you had a 1977-78 Dual disc front set of forks, you could use the brakes and the wheel on that with minimal fuss. Someone else has said you need to make an adapter but from what I can see on my 1978F, it looks like the 1982 brakes will bolt on if you have the mounting brackets from the 82 as well.

the rear shocks will bolt on to your cb750 and will raise the ride height about 1 inch maybe 1/2 compressed. They were a back in the day mod for SOHC cb750s. However, I will say that factory shocks in general are not the greatest things in the world, if you are replacing stock cb750 SOHC shocks then it will definatly be an upgrade but if you have newer shocks in the back (bought in the last 5 years) then you really won't be doing yourself any favors. They certainly look cool though.

BTW, where are you located? I might want some cb900f parts for my own bike and can help defray the cost of purchasing a parts bike.

[zeus87]

Sarasota, Florida

So i should look for  77'-78' F3 front forks, slide them in and then pull the calipers from the cb900f and put them on the F3 forks?

[eurban]

Is distance between the fork tubes the same as the 750 or the 550/550s?  Is the 650s steering stem the same size as the 500/550s or the 750, or neither?  I am familar with the 650 custom and it had dual discs up front with single piston calipers and a drum rear.  Reverse comstars (not pretty IMHO)  Perhaps the 82 650 Nighthawk had dual piston calipers?

[Geeto67]

Sarasota, Florida

So i should look for  77'-78' F3 front forks, slide them in and then pull the calipers from the cb900f and put them on the F3 forks?

That is about the size of it. If you are dead set on having DOHC forks 1979 CB750F use 35mm forks, standard (non reverse) comstar, and better fender mounts for the DOHC front fender (which hugs the tire and looks awsome) and the dual pot calipers are definatly a bolt on for them.

If you want to use the rear dual piston caliper on your bike as well (with the comstar) you will need the axle mounting bracket as well.