Topic: CB550 AND CB650 SWINGARMS, IS THERE A DIFFERENCE?

[Muk]

I have a 76 cb550 and i am putting comstars on it, the question is , are the swingarms the same width at the rear wheel opening and are they the same length. i did not know if the wheel would directly bolt in without the need to modify spacers or if i should replace the swingarm. and if no one knows would someone be willing to measure thier cb650 swingarm for me so i could compare. any help would be greatly appreciated

[Soos]

Can do.
I have a '79swingarm I can measure.
these are rough tape measure lengths...

outside of dustcap to dustcap where the pivit is is about 9 1/2 inches across.
from the front of the dustcap for the pivit pin to the very end of the rear wheel axle slot it is 21 1/8 inches
outside to outside at end or swingarm where the tire axle goes 10.800. Ask me why i know that one.....

I do know there are differences between the '79 and other year cb650 swingarms.
the pivot bolt is smaller for the '79. I would measure it for you, but it's on my bike. somewhere over 1/2 inch.
The '80-82 use a (better IMO) larger pivot bolt.
The '79 uses smaller diameter tubing on the pivot area.
The '79's swingarm is shorter than the '80-82 swingarms, as well as the dustcaps being different.


I've modified a '80's swingarm to fit my '79 frame, and had to do quite a bit of work to make it work correctly.
Looks nice with all the seams ground smooth and a little filler rod to fill in the low spots. Not show quality, but at 50/50(MPH/feet) it looks sweet.
The '80 swingarm is, dunno how much offhand, but is narrower than the '79's.
Length is 1+ inches longer than the '79 swingarm. I can check back on how much later.



l8r

[Muk]

Thank you very much

[Muk]

ok why do ya know the 10.8 across?

[Soos]

The '80's swingarm I had modified to work sprung inwards because i had welded most of the seams in.
After I had gone through the effort of cleaning up all the welds visible, I had phosphated and powdercoated it.

Only to try installing it and find the legs had bowed together, making the opening for the tire not wide enough.

So i had to re-sandblast... let me tell you the factory paint was EASY to sandblast compared to blasting off the powdercoat...

Then I had the fun of straightening the arms of the swingarm to keep the width correct to fit a tire.
At 10.800 outside to outside, there is about 0.030 play room to install the rear tire.


THEN I had to re-phosphate, and powdercoat it.
Looks great now... but it was a PITFA having to teardown that swingarm twice!!!!

l8r

[Soos]

I measured the bolt on my '79 is is a 14mm bolt.
The center of the pivot bolt to the center of the shock mount hole is 17 1/2 inches.


I looked around, I thought i had a swingarm off a '80's, and i found it.
It is off a '82 cb650sc
the bolt is a 16mm bolt.
From outside to outside of the dust collars is 9 3/16 inch.
from tip to tip it is 22 1/2 inches long.
center of pivot to center of shock mount is 18 3/4 inches.



I'm sure there are more differences between the cb650 years as the manual I have shows wheelbase for the different cb650's, (US available i believe) and there are 4 different ground clearances given, 4 heights, 3 widths, and 3 length measurements given.
And thats only for the SOHC 650's, they were available in the US for 4 years?


The two i have measured are a bit different.
Now i rember why i modified that '80's swingarm for my '79... drop the d*mn@d seat height.....

hope this helps.....
PM sent back...


l8r

[Muk]

interested in selling any of the extra swingarms? the 79 seems to have the same bolt diameter.