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Three things work in conjunction - the torque characteristic ,the gearing and the shape of the needles in the carburettor. If you have high overall gearing, you tend to use more throttle, so you are more onto the taper of the needles. A slightly over-rich mixture gives less power. I use 6D Mikuni needles which are the leanest for my 34mm Amals. With close ratio gears and very high overall gearing - that gives the fastest acceleration. Commando motors are different because of the heavy crank. When you open the throttle, you compete with the crank inertia. If you open the throttle quickly, you often use more of the needle taper than you need, so even with more throttle, the bike does not accelerate as fast as it can. It is very deceptive. The only way to findout what works is to try all options, but the only way to find out you have improved torque is to raise the overall gearing. If you don't do that, the bike gives the impression that it is accelerating as fast as it can. If you lower the gearing with the heavy crank, the bike does not usually accelerate faster.

<blockquote data-quote="acotrel" data-source="post: 660094" data-attributes="member: 4295"><p>Three things work in conjunction - the torque characteristic ,the gearing and the shape of the needles in the carburettor. If you have high overall gearing, you tend to use more throttle, so you are more onto the taper of the needles.&nbsp; A slightly over-rich mixture gives less power.&nbsp; I use 6D Mikuni needles which are the leanest for my 34mm Amals.&nbsp; With close ratio gears and very high overall gearing - that gives the fastest acceleration. Commando motors are different because of the heavy crank.&nbsp; When you open the throttle, you compete with the crank inertia.&nbsp; If you open the throttle quickly, you often use more of the needle taper than you need, so even with more throttle, the bike does not accelerate as fast as it can.&nbsp; It is very deceptive. The only way to findout what works is to try all options, but the only way to find out you have improved torque is to raise the overall gearing.&nbsp; If you don&#039;t do that, the bike gives the impression that it is accelerating as fast as it can.&nbsp; If you lower the gearing with the heavy crank, the bike does not usually accelerate faster.</p></blockquote><p></p>

[QUOTE="acotrel, post: 660094, member: 4295"] Three things work in conjunction - the torque characteristic ,the gearing and the shape of the needles in the carburettor. If you have high overall gearing, you tend to use more throttle, so you are more onto the taper of the needles. A slightly over-rich mixture gives less power. I use 6D Mikuni needles which are the leanest for my 34mm Amals. With close ratio gears and very high overall gearing - that gives the fastest acceleration. Commando motors are different because of the heavy crank. When you open the throttle, you compete with the crank inertia. If you open the throttle quickly, you often use more of the needle taper than you need, so even with more throttle, the bike does not accelerate as fast as it can. It is very deceptive. The only way to findout what works is to try all options, but the only way to find out you have improved torque is to raise the overall gearing. If you don't do that, the bike gives the impression that it is accelerating as fast as it can. If you lower the gearing with the heavy crank, the bike does not usually accelerate faster. [/QUOTE]

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