Author Topic: 1978 cb750f swingarm on 1978 cb750k frame  (Read 171 times)

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Online Dime

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1978 cb750f swingarm on 1978 cb750k frame
« on: October 30, 2024, 05:51:12 pm »
I am wondering if the 1978 cb750f swingarm is a direct bolt up to my 1978 cb750k frame?

The reason I am wondering is because I will be running disc brake on the rear and the f swingarm is already setup for the disc.

Otherwise I have to cut the bracket off of mine and weld it to the top like the disc setup whereas the bracket for the support in on the bottom of mine for the drum setup.

Thanks in advance.

Offline Alan F.

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Re: 1978 cb750f swingarm on 1978 cb750k frame
« Reply #1 on: October 30, 2024, 06:19:00 pm »

Online Dime

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Re: 1978 cb750f swingarm on 1978 cb750k frame
« Reply #2 on: October 30, 2024, 06:29:12 pm »
Right here in reply#5

http://forums.sohc4.net/index.php?topic=139745.0#lastPost

Ok so it seems like the f swingarm and the k swingarm is the same for 78 except the f is setup for disc brake.

Thank you

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 1978 cb750f swingarm on 1978 cb750k frame
« Reply #3 on: October 30, 2024, 08:40:39 pm »
On the left side, the 77 and 78 F and K both had the double row output shaft bearings which both created the 10mm offset all the way back. Front sprocket cover, swingarm, chain guard, shock mount, rear sprocket flange. That is all equal.

The one piece I do not know is the difference in the lengths if so of the 2 swingarms. 
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Online Dime

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Re: 1978 cb750f swingarm on 1978 cb750k frame
« Reply #4 on: October 30, 2024, 10:54:26 pm »
On the left side, the 77 and 78 F and K both had the double row output shaft bearings which both created the 10mm offset all the way back. Front sprocket cover, swingarm, chain guard, shock mount, rear sprocket flange. That is all equal.

The one piece I do not know is the difference in the lengths if so of the 2 swingarms.

I went ahead and ordered the f swingarm.  Will report back I'd there is a difference in length

Offline 70CB750

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Re: 1978 cb750f swingarm on 1978 cb750k frame
« Reply #5 on: Today at 02:05:44 am »
i have done the same combination for Red - and she is a K3 frame with 78f swingarm, disc brake in the rear and 914rr rear master cylinder. 

Online Dime

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Re: 1978 cb750f swingarm on 1978 cb750k frame
« Reply #6 on: Today at 02:53:16 am »
i have done the same combination for Red - and she is a K3 frame with 78f swingarm, disc brake in the rear and 914rr rear master cylinder.

I think a master cylinder came with the parts stash in the kz1000 ltd stuff. Will have to double check. Definitely have the caliper and floating mount. Didn't have the mount support but that is coming with the 78f swingarm. I think I did pretty well on the 78f swingarm. $92 Canadian to the door.

Online newday777

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Re: 1978 cb750f swingarm on 1978 cb750k frame
« Reply #7 on: Today at 03:56:21 am »
i have done the same combination for Red - and she is a K3 frame with 78f swingarm, disc brake in the rear and 914rr rear master cylinder.

What is this 914rr rear master cylinder?
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A