Ignition advance key and carb adjusting
 

I've been having a look at the dyno readout on JHS Racing's site after they fitted the new Woodruff key, and I was wondering if shimming the carb needle might fatten up the mixture in the middle to produce a smoother torque curve.

I can see the new key boosts the torque between 2.5k - 4k, where I spend most of my time riding, but it flattens out again until about 6000. Is it fairly straightforward.....?





No, thought not :cry:

Shimming the needles is only really applicable to US bikes, as they don't have grooved needles the same as we do. The idea being that the US bikes will be harder to fool about with as their emissions laws are stricter and include regulations as to what can be adjusted as well as what the adjustments end up giving.

If you want to try alternate needle positions, you may well find that lifting by one groove helps a little, it's hard to be prescriptive as different bikes and different pipe/filter combinations respond differently.

No point altering the fuelling if you have the stock can and air filter. If you chop them in for more free-flowing jobs you really need to upjet as shimming only richens the midrange but leaves the top end lean (not good). Proper set-up is done on a dyno though.

Surely with the slide all the way up the fuel mixture wouldn't alter?