I need a little advice. I had have the stock BME exhaust 1 1/8" tube straightened and welded but when I got it back from a (friend of a friend) welder he thought it would be better to replace the tubes but all he had was 1". What do you guys think, will this extra restriction cause the engine to over heat or cause any other problems?

In my opinion it should not cause any problems at all...

Bob

It should be quieter.
I have flown my plane without mufflers and I find that the engine runs more consistant with mufflers.