Topic: Engine rattling noise on CB550? Help plz.

[neurotoxin312]

Hey guys

My CB550 is making this rattling noise coming from the top part of the engine. I purchased it from the seller this way and he told me that it is most likely the cam chain that's loose. When I adjusted the cam chain the engine still makes this noise. The rattling kind of increases as I rev the engine. It definitely sounds like a chain of some sort that's loose or something. Any suggestions of what I should do without having to tear apart the engine? Is it safe to operate the engine minimally in this condition? I haven't really taken the bike on more than a 10 mile journey thus far.

[arncruz]

how many miles on your bike?  I had a similar rattling in my CB550.  I took it down to the cylinders and found out that my camchain tensioner was not functioning.  This made the cam chain loose and gave the rattling noise on the top end.  There was signs of rubbing on the camchain tensioner.  You could have a similar problem.

[Bootsey]

After a while the cam chain will stretch beyond a point of being adjusted, then it's time for a new chain.

[neurotoxin312]

Bike has 60 000 miles. I figured that its either the cam chain tensioner is bad or the chain itself. Which would be the easier to change and can it be done with having the engine mounted on the bike?

[Bootsey]

Yeah, at 60,000 theres a fair chance the chain is done, depending when it was last replaced. Have you done any other maintenance on the bike? How does it run otherwise? If no other regular or recent maintenance has been done, might be time to check a few things.

I haven't done so, but I'm pretty sure you can pull down the 550 top end with the motor in the frame.
Some cam chains are endless, which means the crank has to be pulled out to replace the chain, others have master links, and can be done with the valve cover off.

As for the tensioner, if the adjuster rotates, and springs back to centre, it's probably OK. But there is 2 cam chain guides, which I'd suggest inspecting. This will require removing the head as a minimum. 

[TwoTired]

Sometimes, I'm, disappointed about the advice I read here in the forum.

I check the valve adjustment.  In fact, do the entire 3000k tune up routine.

Does the tensioner lock nut tighten?  Is it stripped.  Did you verify the stud post can turn and is free.  It only need to move about 1/8 to 1/4 turn.

The cam chain lasts over 100K miles, unless you run without oil.

The tensioner shoe can wear out/or and fall off.  Particularly, if the standard adjustment wasn't followed and a PO made it too tight in an effort for it to be totally quiet.  Hard to believe it is worn out out without some sort of abuse.

It matters what year your bike is.  Prior to 76, the cam cover rocker shaft pivot holes can elongate, which allows the rockers to hit the inspection covers and make noise.  Use a stethoscope or a screwdriver handle nested in your ear to probe where the noise is loudest.  Remove the tappet inspection covers and look for signs of contact.

You can also remove the right and left cylinder cover end caps/plugs and see if the shafts are still centered in the bore.

There is a lot you can check before tearing it apart looking for troubles.

All top end work can be done with the engine in frame.  However, if you insist on changing an endless loop cam chain, the crank has to come out, cases split, which requires removing the engine from the frame.

[Bootsey]

Sometimes, I'm, disappointed about the advice I read here in the forum.

I check the valve adjustment.  In fact, do the entire 3000k tune up routine.

Does the tensioner lock nut tighten?  Is it stripped.  Did you verify the stud post can turn and is free.  It only need to move about 1/8 to 1/4 turn.

The cam chain lasts over 100K miles, unless you run without oil.

The tensioner shoe can wear out/or and fall off.  Particularly, if the standard adjustment wasn't followed and a PO made it too tight in an effort for it to be totally quiet.  Hard to believe it is worn out out without some sort of abuse.

It matters what year your bike is.  Prior to 76, the cam cover rocker shaft pivot holes can elongate, which allows the rockers to hit the inspection covers and make noise.  Use a stethoscope or a screwdriver handle nested in your ear to probe where the noise is loudest.  Remove the tappet inspection covers and look for signs of contact.

You can also remove the right and left cylinder cover end caps/plugs and see if the shafts are still centered in the bore.

There is a lot you can check before tearing it apart looking for troubles.

All top end work can be done with the engine in frame.  However, if you insist on changing an endless loop cam chain, the crank has to come out, cases split, which requires removing the engine from the frame.

Apologies if my post wasn't accurate. Definitely wouldn't have thought a cam chain would ever have that life span, learn something every day.