Topic: '82 650sc warning buzzer?

[Jegs]

I'm getting a really annoying warning buzzer type sound from somewhere when I reach roughly 60km/h. It sounds similar to when you leave your car keys in the ignition and open the car door. Any ideas what it could be, or where to start looking? It stops when I get back down to about 10km/h, so its a little bit hard to assess since it only happens at speed.

[Deltarider]

Is it a P(olice) model? A model for the Asian market?

[Jegs]

No its difinitely a north american model, and Ive never hear of a CB650SC used for a police cruiser... but Im also pretty positive thats not the case either.

[Deltarider]

I remember in some countries in SE Asia you had all sort of devices to prevent people from speeding. In Malaysia, if I remember well, all commercial vehicles had an orange lamp on top. If they we're going about the maximum speed the lamp would start to blink and if they were going too fast for too long the lamp would light up constantly drawing the attention of the cops alongside the road.
Although I've never witnessed it myself, I've heard of another country (could be Japan) where horns would sound automatically and I was told they could only be switched of by a policeman (with a special key) who ofcourse would write out a ticket at the occasion. Could it be your bike was ment for those markets?

[Jegs]

I highly doubt it. As far as I know, this particular bike has never left Canada. The PO lives in the same city as me, as does the original owner. Also, it does die off when I get back down to approximately 10km/h without having to touch anything. It sounds like it just slowly loses power and dies. Any other suggestions?

[trueblue]

Are you getting oil to the top end of the engine?  The sound of the cam seizing into the head has been best described as 2 cats fornicating under the tank.  I've never heard it myself, touch wood.  The best way to find out is remove the cam covers (the ones you remove to adjust the valves) while the engine is running and see if there is oil splashing around.  Be warned it will probably make a mess.

[Bodi]

If it doesn't buzz with just revving the engine, something that only moves when the bike is moving is your problem.
Put the bike on the centre stand (on a piece of plywood helps to get the wheel higher) and run the bike in gear to see if it is the chain or rear wheel somewhere.
Check for clearance between the rear tire and frame etc. with you on the seat (off the stand of course!), look for off wear on the tire or what it could hit. Same with front tire.
The front wheel is tougher to turn at speed while on a stand, obviously. You can disconnect the speedo drive at the speedo and go for a ride to see if the speedo was buzzing.
I've had strange buzzes that were traced to wires inside the headlight shell vibrating on it or the headlight reflector. But generally anything like that will buzz with just revving the motor to where it would be at the speed you hear the noise. Same with engine problems, riding load won't make much difference and the noise should be there with it not moving.

[Jegs]

Thanks for the suggestion trueblue, but as bodi suggested, it only happens at speed, so it's definitely a moving problem.
It's funny you mentioned the gauges and headlight, because that was my initial thought. It sounds like its coming from my gauges but I couldnt get them apart to see what exactly was causing it. It sounds a lot louder than just a wire vibrating though. The guages are off a 70s CJ360T. I'm going to try disconnecting my speedo and then tach to see if I can narrow it down I guess.

[ShermanPain]

This might be a long shot, but i had a similar noise on mine and it turned out to be the keyring i had resting on the fusebox cover between the bars. at speed the vibration of the bike would make the keyring buzz. thought it was something in the headlight at first then i put my hand on the key and it stopped. dunno if that is the case for you but check it out if you've got  a keyring on your key

[Fritz]

I've had a speedo that started screaming whenever the temperature fell below 50°F above 4000RPM.
It took a while to identify the source of the noise...