Fitting A 28mm Keihin To An 07 Rev3

[dan williams]

Think about it. A larger carb is only going to make a difference at wide throttle openings. The difference between a properly tuned Mikuni and a properly tuned Keihin isn't as big as the other changes in the engine. There are a lot of differences in my '08 270 compared to my '05. Stock throttle tube on the '08 is a fast throttle white tube, the intermediate muffler is different on the '08. The '08 270 has no primary side flywheel weight and the crankcase volume is reduced. I believe the '08 also has a different head with slightly higher compression.

So if you want more snap off the bottom end you should be focussed on the things that have been done for the factory bikes for years. A high compression head, advancing the timing, shorter head pipe, matching transfer ports and basically anything that makes the engine a more efficient air pump. Just remember that even though these mods will make a bike hit harder most will also make it run less predictable at low RPM.

Jordi, Dougie and Albert won a lot of world championships with that same Mikuni. Despite some of the earlier posts on here the Mikuni is not the root of all evil. To be blunt it's a lot more tolerant of conditions then the Keihin and easier to tune as well.