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Rear End Noise

SuperRat

CB750 Member
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Location
Muskego, WI
I just replaced the chain and sprockets on my '80 750F. Now I'm getting metallic swooshing sound when the bike is under load. No noise when I'm costing, only when accelerating on steady state throttle. All the spacers are in the correct postion and the rear wheel is straight.

Any help or suggestions would be great.

Thanks,

John
 
Too tight comes to mind...............

They switched from 630 to 530 chain that year, are you sure all the parts match? Thinking they shouldn't even work at all but................

Is the rear sprocket made of aluminum? I've seen copycat parts to not be centered say inside bolt center to outside OD or the sprocket teeth.
 
I have a feeling its the sprocket. When I spinthe wheel, it feels like the ring thats riveted to the sprocket isn't true. Not sure if just the ring edge is bent or if the whole assembly is bad. I'll have to pull it off this weekend and do a more thorough check.
 
You'll see bent in the runout instantly. The steel ring is not supposed to touch anything if mounted correctly, it only contacts if chain tries to jump. If touching then bent. Easily fixed in 60 seconds unless the whole OD is butchered. I myself tend chains regularly and commonly remove the steel guard ring.
 
No, the ring isn't touching anything. if I brace my finger between the ring and the shock and spin the wheel, I can feel a gap come and go. Not the most scientific method, I need to get a run-out gauge. Is there a brand of sprocket you recommend if I do have to swap it out?
 
Man I just buy them, never had any trouble other than with one like I commented on, back when bike was so new none were out in the marketplace yet. The bike shop had a guy who custom cut them, his work was not as good as he cracked it up to be.

Steel ones can commonly be better than aluminum.

The ring if not touching shouldn't be making any noise, BUT, if cut off center then bolt pattern may be as well, since both are indicated in commonly at the same time.

Tighten chain up to almost too tight and then roll wheel around, if it is tighter in one spot and looser in other then sprocket is out of whack. The bolt pattern and teeth are not concentric to each other.

It can be corrected if one has access to like a mill, to set up on the OD of teeth then go back and slightly repunch holes out and redress the center bore if needed. What I did to pull mine out of the trash many years ago.
 
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