Optimum exhaust diameter ?

[scorcher]

Now got a rattly exhaust ( grounded x 3 times and a rock encounter )after a week of hooning on the rough Zummerset roads.Its already been sleeved but now rattles ( and is annoying )so maybe is the best time to have a new stainless system made up. Is there a min/max exhaust diameter to adhere to ( noise not a problem )but don't want to over do it back pressure wise. Any Ideas?

[Phil Tudhope]

Aren't the original, standard, Griff exhausts stainless? Mine certainly look stainless steel from the connection alongside the gearbox area back to the tailpipes.

Phil.

[scorcher]

Will JP make want you want or do they just have a single/std style.Fancy a change from the two singles.Perhaps a pair of twins?

[scorcher]

Thanks.Will make more enquiries.