Mikuni pilot jetting

Mwood7800 said:

What if when running a 35 pilot jet the screw has to be 4 turns out. With the 30 only 2 screws out but it is hard to start. Same jets in both carbs. My red bike has a 35 and everything else is the same and it the screw turned out only 2 turns and starts fine. Not sure why carbs are different

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Your observation is correct; going to a larger larger idle jet should require more idle air. I have 3 thoughts about this: 1) your choke plunger may not be seating allowing unwanted additional fuel to have an effect on all stages of carburation, but hitting the hardest at idle RPMs. If so this can be caused by a plunger that may be sticking in it's bore, an eroded seat in the carb body or a tired/torn rubber pad on the plungers bottom. 2) your float level may be too high. The correct float arm setting is when the arms are both equal and parallel to the float bowel seating surface. 3) the idle jet may not be seating in its bore, or you may have the wrong jet; there are 3 different idle jets that will fit the VM. The correct idle jet is 14mm long, has a 4mm thread and has 4 holes, in 2 pairs, 180 degrees apart; not a strong possibility, but worth checking.

Best.

New Mikuni. Everything checks out. Will check the float height.

A few observations of mine which may or may not be welcome. A couple of years ago, I sourced and had fitted an O2 sensor and a fuel/air ratio gauge. I am a self described tuning dunce. However, once I had this fitted, I started to learn something about carburetion. I discovered that a Commando will run very well across a wide range of jetting. With the gauge I was able to dial it in to perfection, where a weak kneed stab on the kickstart would crank it up every time, make it run beautifully and give me better than 60 Imperial mpg. It has become an absolute delight. Try it, you'll like it and it gives you a new insight.