Spent some time on a rolling road last week and tried out all 3 x length trumpets.
All 3 x lengths did give different figures but the 62mm. trumpets which actually came with the carbs. from new actually performed the best with 158.6 bhp / 6533 rpm and 125.8 lbft / 4753 rpm.
The 75mm. trumpets were 2.2 bhp down and the 30mm. trumpets were 4.6 bhp down.
Not a lot I will admit but every little bit counts.
I am running with 36mm chokes and unless anyone knows otherwise with this setup 165 bhp is probably the best you could get anyway, without going to 48 DCOE's and 42mm. chokes.
The 75mm. trumpets do look good though, but have had to come off for the 62mm. trumpets which still fit O.K. inside my existing Pipercross foam filter setup.
All day Track Day booked at Brands Hatch on the 10th. November to go out and play.
GP