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1976 CB750F Swingarm Swap

ChrisH

CB750 Member
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Hey guys,

New to the cafe seen. I have a 1976 CB750f.

I recently bought a swing arm off a 1979 CB750f (so I thought) on eBay because I had read they were interchangeable....It just came in today, and it looks like its off an 80's+ bike. So it's too wide to fit in my frame.

After reading some old forums, It looks like I'll need to machine off a 1/4" (1/2" total) of material on each side of the swing arm. I will also need to drill a 5/8 hole through the mounting points on the bike.

Is this correct? After examining the two swing arms, it looks like the 1979 is offset more to one side in comparison to the 1976. My concern is - if I machine off a 1/4" of material on each side of the swing arm, it will not be centered correctly on the bike. Does anyone have experience with this? I'll attach some photos so you guys can hopefully see what I'm talking about.
 

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You definitely don't want to change the offset. If you do you'll have to mess with spacers in the rear to keep your wheel and chain aligned, and that might cause clearance issues and may not even work. I would think it would be better to match the orginal swingarm. Time to take some detailed measurements.
 
I just did this with a straight edge, a square, a laser and markings on my floor. Removing 1/4" on each side is correct. However that is not a '79 swing arm. It is an '80+. The '79 has the same internal diameter for the mounting bolt and no frame modifications are needed. As a matter of fact I am using the same needle bearing kit and swing bolt from my stock set up. Don't go down the rabbit hole with that '80+ swing arm. It is not worth your time.
Now going with the '79 you will need to lengthen your shocks unless you want to have the rear lowered.
 
Hey guys, I really appreciate the replies. I would like to swap the swing arms just because I prefer the round tubing vs the square tubing. @Snider1970 thanks for the insight. I agree with you on going with a 79. However, the ones I’ve come across on eBay are mislabeled as a 79, and are actually off a 80+ bike.
 
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