1982 Seca 750 clapping sound

Clapping sound for like 4 seconds and goes away....only does it I thing going slow in first while turning...I notice it when I pull the bike into my fenced in back lot area sometimes pulling into gas pump....never happens at any other time

Does not last near long enough to pin point it

 

Any guess on whether it is an engine noise?

 

Loose exhaust pipe headers?

 

the noise will be echoing off the close surroundings , listen closely without helmet on, see if you can pinpoint it

 

IDK

If it was wouldn't it do it all the time?

 

When I got my 900f there was a knocking sound from the engine and I was concerned at first until I found out it was normal all the shaft drive bikes do it. It was the damper cams on the middle third gear re-engaging parts 4 and 5 on the drawing.

https://www.cmsnl.com/yamaha-xj900f-1991-4bb1-france-214bb-351f1_model38005/partslist/0018.html

Put your bike on the centre stand and start the engine and blip the throttle to see if you can hear it. It is more of a clunking sound to me, just so you know the shaft drive bikes do this.

 

Yes sounds like its coming the middle of the bike

 

I bet it is the middle drive gear. Rev the engine and get a mechanics stethoscope or a long screwdriver and put your ear to it. You will be able to identify the noise inside the crankcase. Post a video on here or Imgur and post the link here . You might be able to record the noise on your phone. It happens when the revs are decreasing.