Speedster & Dave,

Yep, that is kind of what I am looking for, but I was hoping not to buy anymore parts :-) f I had to summarise, the question would be:
Can I take a straight-through pipe, drill a hole in it, tap the nipple in, and just have the pipe exit the cowl without any muffler?
The main concern of mine is the tank pressurisation.

There is little space in the cowl for the part mentioned on your site Dave, but it does look cool. It also means I would have to mount the engine inverted, and I was hoping to keep it at 90 Deg.

Thanks for all the help

Regards, Andy