bobh
Member
Rule of thumb - 3rd in 30's, 4th in 40's, 5th in 50's. Works fine for all the (modern, 6-speed) bikes of around this capacity that I've ridden. Even works for the Fazer8 now that I've dropped a tooth on the front sprocket. Thousands tend to be a gear lower.
Running the engine at very low revs does give it an easy time mechanically. But because of the relatively high state of tune of bike engines (mostly over 100 bhp/litre) economy suffers because the valve overlap time is long, so some of the fresh charge goes straight out of the exhaust. A friend with a Suzuki V-Strom 650 was using high gears, and I suggested he try letting it rev more freely. He noticed an immediate improvement in economy on his daily commute.
As a general rule, twins have a useful rev range of about 3:1, i.e. if the redline's at 10K rev/min, as on the MT-07, it will start to make usable, smooth power at around 3.3K. That pretty much corresponds with my experience - I tend to stay in the 4-6K range most of the time on the road.
For comparison, the usable rev range of fours is 4:1 (typically 3.5K-14K for a 600 cc bike, or 1.5K-6K for an average petrol car).
Running the engine at very low revs does give it an easy time mechanically. But because of the relatively high state of tune of bike engines (mostly over 100 bhp/litre) economy suffers because the valve overlap time is long, so some of the fresh charge goes straight out of the exhaust. A friend with a Suzuki V-Strom 650 was using high gears, and I suggested he try letting it rev more freely. He noticed an immediate improvement in economy on his daily commute.
As a general rule, twins have a useful rev range of about 3:1, i.e. if the redline's at 10K rev/min, as on the MT-07, it will start to make usable, smooth power at around 3.3K. That pretty much corresponds with my experience - I tend to stay in the 4-6K range most of the time on the road.
For comparison, the usable rev range of fours is 4:1 (typically 3.5K-14K for a 600 cc bike, or 1.5K-6K for an average petrol car).