Well, had the six speed gearbox installed and working on the road since last October. I have probably only covered around 4000 miles
The new gearbox runs brilliantly.
I live in an area with lots of hills and winding roads that gives any gearbox a run for its money. The new gear has performed faultlessly and I am very pleased with the end result. Please remember the extra gear fits between fourth and fifth so it does not change your overall gearing just gives you another one to play with. When you are pulling out of a corner hitting 8000rpm in fourth then fifth and powering up in sixth, its just brilliant and has me rapidly chasing down other twins in front of me.
I have had the overall gearing almost stock for the last few months, 19/44 with 160/60 tyre 135mph@8000rpm in sixth. With the many hills and draconian fines for speeding, I have just reduced the overall gearing to 18/44 129mph@8000 in sixth. This has produced a fantastic snap to acceleration with the front wheel skimming across the ripples in tarmac, I just have to be conscious of the occasional wheelie here and there but life’s good. Lol
I generally do not rev my bike over 7500rpm but yes I have hit 8000rpm in sixth gear. (on private roads officer)
Was the extra gear worth it, difficult to answer, if it could have changed the overall gearing, then yes, but with the gear slipping in between two others, for the road then probably not. But If you’re a Thruxton Cup racer, it would give you a massive advantage.
Was it with the expense, hell yes! Would I sell the gearbox – only if offered the right money, so I could finance other mods
Hava already done a few things to the engine
4mm Oversize inlet valves
2mm Oversize exhaust valves
Ported & flowed head 320cfm
Billet barrels ‐ http://www.stabbarps‐auto.com/welcome.html
1089cc Wiseco kit 10.5‐1 CR pistons‐ http://www.bonnevilleperformance.com/
101mm x 68mm bore & stroke
Barnet racing Clutch
Heavy duty clutch springs
Shot preened gears and shafts