Cheers Batman,thanks for the tips & I have read similar information in your forum before but unfortunately suffer from the human condition of "but maybe I can make it work" so had to build a larger exhaust to find out!..but somehow wasted time in the workshop still seems like a positive thing!..I believe my friend does Know his stuff, He's built raced & won on British machinery at the IOM classic TT & is an amazing old character who I cherish spending time with so when he offered to do the exhaust calcs I figure its another opportunity to maybe learn something..& he may come up with the same figures as you guys have discovered work ...but its all just part of the motorcycling stuff that I love...Thanks for the Forum!

I'm with Ruttly ,I'd like to hear your results. If you've read up ,you know that if your planning to keep the motor stock ,that the stock header,a Dyna muffler ,white spacer mod /rejet and a better air cleaner is the way a lot of us have gone. It gives a remarkable difference in driveability,and a bit more horsepower ,with very low cost,but I would never stop anyone from trying something else. I am on this site as much to learn as to try and help others. good luck!