CB 450 First start up (what is this noise?) - VIDEO

[p71sohc]

OK...Today was very productive.......But.....Does anyone know what the high pitch noise is when the bike is running? It sounds like a loud bird chirp. There is plenty of oil and we checked the front valve cover....looks like oil is getting up top. I cant really pin point were the noise is coming from either so any ides would be very helpful. Hopefully with all those 450's out there someone has experienced this before.

Thanks, Joe

Cb 450 first start

 

[teazer]

Lots of blue smoke, inability to idle but reasonable looking compression - I'd guess a broken piston ring. It could be an air leak of some sort. Have you tried a stethoscope on the motor to see if you can locate the noise?

Or grab a long screwdriver and put the tip on the motor and your ear against the handle and move it from spot to spot to see where it's loudest. It's an inexact science but sometimes it's useful.

 

[p71sohc]

ill have to try listening again. I'm a little afraid to keep running it though because if there is damage I don't want to make anymore then necessary. my friend Andrew poured some oil (tiny bit) down the spark plug holes for lubrication so I wonder if that's the blue smoke from it being burned off?

 

[rockcitycafe]

did you rebuild this motor?

 

[p71sohc]

Yes it was rebuilt. has Nos intake exhaust valves, Nos pistons. Everything else is original with roughly 5k on original parts

 

[p71sohc]

found the noise today. It was a vacuum leak at the carb and head. Old gasket material was still on there so it didn't seat well. lesson learned . Thanks for the help