katana backfire

[davementia]

Hi all
Have been busy so not much time for the bike.
Have been starting or riding it about 1 or 2 week intervals and every time i start it after this period it turns over fine but it backfires without fail.
After this it runs fine.
Any suggestions

[Pedda]

Backfire through the carbs or out of the exhaust?
A cam timing checkup is always helpful (things wear after all those years) as well as a valve adjustment.

[davementia]

Hi pedda
The backfire is through exhaust .
I think i need to check it all really. I already had found the cam chain tensioner was stuck

Dave

[callyboy]

running lean? I always thought it was fuel igniting in the zorst.

Pete

[Katgeezer]

Air leaks in the exhaust? Probably not but an easy check if nothing else.

Or possibly a weak spark initially which could be cdi or generator or even just a suspect plug/lead. Sadly you'll probably end up checking all that lot