Topic: Cb550 engine noise (video link)

[gregripko]

Cb550 vibration noise

Get a random chain vibrating sorta noise when I idle around 1,000. Seems to go away when I'm 1,100 +......any ideas?

[scottly]

Sync your carbs.

[gregripko]

Whats the noise then? Sounds like a rattling

[scottly]

The noise is caused by an uneven idle, in my opinion. Nothing to worry about.

[Tews19]

This the bike you made a thread on about the shop replacing the head gasket and rebuilding the carbs?


First thought was cam tensioner.

It could be that the carbs need to be sync'd as Scottly stated.. But I would be worried due to the fact you had it in the shop...

Maybe share the issues you had when you got it back and what work was done when at the shop..

I take it the shop never fixed it?

[gregripko]

Same bike yes.... It probably does need a carb sync.... Looking online I see rattling is often associated with out of sync bike

[Tews19]

Didn't the shop sync them when cleaning them?

[gregripko]

Doubt it

[Tews19]

Didn't they tell you what services were done for what you paid for?

[gregripko]

Head gasket replace

[DustyRags]

The chain sound (background hiss) is your cam chain. Hard to tell how loud it actually is, since the video likes to distort that. Run your cam chain tensioning procedure as per the manual. The intermittent rattle is the bottom end from a rough idle. Check your timing and adjust it as per manual, and if that doesn't fix it, sync your carbs. It's a bit fiddly, but not all that hard really.

[Fritz]

Syncing your carbs - after a full 3000-mile tuneup - will improve the rattle. But it will never go away completely at idle revs (1000RPM).
It's caused by gear lash and the momentum of the clutch basket together with a stretched primary chain. On the 550 the primary does not have a tensioner, so all the lash will be transmitted to the gear box. The longer you let the bike idle with carbs out of sync, the faster the primary will stretch. At some point the stretched chain will rub on the engine case, but it takes a long time for real damage to occur.
If the noise does not go away above 1500rpm in neutral with synced carbs, it might be time to open the motor...

[gregripko]

Thanks for the responses....going to sync carbs this weekend and see the results....seems like the rattle goes away above 1,100 rpm