exhaust pipework
 

Im just trying to make some exhaust pipework for my 620 DD bike to get down to a singel can. How important is diamiter of the pipe. Will 10-15% difference either way matter much or could it all be sorted on the Dino? :frog:

If you read Moto-One Performance notebook it would seem quite important - I've been looking into this myself with a view to making a better set of downpipes and collector for my 800 race bike.
I think the 620 has a 40mm diameter pipe like my 800ss', dropping below this seems to affect power adversely if Moto-One's experiences are anything to go by when they were playing with the 750ssie. If you do make pipes then it's important that you ensure they do not restrict the flow of gases exiting the exhaust ports.

Do you think a bit bigger will muck about with the back pressure or anythig. Its all a bit new to me and wont really know what the power is like untill it goes on the dino after Cadwell. :puzzled:

I haven't got a clue about the back pressure bit. If I were you I would go to someone who is happy to make proper customer exhausts...like Jorge at Renegade or MHP. It'll cost but, it'll probably be the best way cos they will develop it on a dyno.

I was guessing that would be the case just wanted to have a stab at the cheap option first.

It might not be so cheap when you've factored in your time that might be better spent elsewhere. If you do fabricate your own pipes I've be interested to see the results.

I'm lucky - I get free dyno time so I can fiddle to my heart's content so, I have the opportunity to test things like different pipes.

Interesting article over at Moto-one implies that the std crossover is more than adequate because the same design is used across a range of bikes so, as far as I can see, if the downpipes match the exhaust port size and they are of 40mm diameter then you needn't worry too much about getting an alternative design built.

Moto-One article

try this guy, very well priced

Wayne, 0115 9635556



Chris.:burn: