BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: john sever on 11 Aug, 2021, 03:45

Title: Exhaust uneven
Post by: john sever on 11 Aug, 2021, 03:45
Hi 
I have just started up my 1970 A65L after a full engine rebuild (by someone I know is a very good on BSAs). I'm using after market Dunstall style mufflers (IMO good quality). At idle, when I put my hand just behind the mufflers the l/h one has a lot more "strength" in its output. When I rev the motor the r/h one comes on strong.  Is this normal?
Thanks
John
Title: Re: Exhaust uneven
Post by: DAVE BRADY on 11 Aug, 2021, 07:02
Hi John,

I would say not normal but as you have only just fired up a fresh engine it could be that in one cylinder the rings are sealing a bit better.  It may also be worth thinking about the tappet clearances and if the valves are closing properly.
If you have a compression tester check that both cylinders are the same.  The result could either confirm or dismiss the above.

Dave.
Title: Re: Exhaust uneven
Post by: john sever on 11 Aug, 2021, 08:06
Thanks Dave.  I do have a compression tester so will do that.