Engine rattle, '87 CBX750?

[kiwi cowboy]

me old cbx 750 with 64000 kms on it has a slight rattle.

Only when cold and between 2 and 3 k rpm.

No noise below or above that and goes away when hot.

sounds like the cam chain but dont know why only when warming up and only between those revs.

Anybody have any experiance with this cheers.

[F5 Dave]

first off get the carbs balanced if it worries you, when they are out that can make chains rattle.

CBXs of smaller size had primary chain & think 750 might have & also drive to alternator which was piggybacked from memory 20 yrs on.
My 550 camchain did it at 4-5k.

but if its quiet when warm then don't lose any sleep.

[spanner spinner]

as per other reply could be either of the chains and yes they are rpm dependent as the load comes on and off the chain, the k's are right for a worn out cam chain if the noise gets worse time to get a new one fitted.

[kiwi cowboy]

first off get the carbs balanced if it worries you, when they are out that can make chains rattle.

CBXs of smaller size had primary chain & think 750 might have & also drive to alternator which was piggybacked from memory 20 yrs on.
My 550 camchain did it at 4-5k.

but if its quiet when warm then don't lose any sleep.

Yes i could ballence the carbs at some stage but it runs good and even.

Yes these have a chain that drives the starter and alternater but when it rattles its sounds like it is coming from the top of the motor so may be cam chain time.

I have been told theres a guy in the north island some were that does a modification to the chain tensioner to make them better as there just a spring tensioner factory so any body know who he is would be good.

Wont be doin much untill spring so may look into it in the colder months.

[kiwi cowboy]

as per other reply could be either of the chains and yes they are rpm dependent as the load comes on and off the chain, the k's are right for a worn out cam chain if the noise gets worse time to get a new one fitted.

yer might look into a new one shortly cheers.

[geoffc]

Check out Team RC17 website. A wealth of information & helpful guys that know heaps about the CBX 750. There is detailed information on your particular issue on that forum. Cheers