Bill,
It shouldn't require choke for too long. If it's still on after around 30 seconds, the plugs are getting rich. (The only thing in this build that is
) An idle stop for ~1200/1300 rpm should be as low as you set it. You need enough rpm at idle for it to want to creep forward. It will happily idle lower but you'll need the creep to stage the bike. A lower idle may rock the bike backwards as you come off of the gas and apply the brake. You want this motor to always want to go forward. It will prevent rookie mistakes in staging the bike. The increased advance from the points plate replacement adjustment for this larger displacement motor will also increase the idle. Intake manifold leaks can be easily found with something under pressure that increases or decreases combustion. If you seat the tubes evenly, they never will leak. Even if a clamp is a little loose, the tubes usually stay sealed. Make sure that nothing near the intake side can be sucked in. (tape, twine, wire ties, wires, etc.) Don't forget the return spring from the linkage to some point on the motor to overcome the tendency to high idle without it. Are you using a quarter turn throttle? For racing this bike, the throttle is mostly run as an on/off switch. The only time that you use part throttle is on the return road. It will be kept under ~1,800 rpm on the return road to avoid attention returning to the pits. A quick throttle may spook a road racer a little, but it works best for quickly opening the carbs as the tree starts counting down. Loading the converter for over 1.5 seconds just heats the oil and slows down the bike. Even if you don't get the maximum rpm under load that the bike is capable of, you will have far better consistency. Test and tune will open your eyes on what you've created. Clamps on fuel line ends are also usually required at tech inspection. You have to use a little overlength gas line to feed the carbs. They can vibrate around some and even pull off a tightly clamped feed line at the worst possible time. ( Yes, I've lost a final when the feed line came off in the burnout box. The clamp was still on so tight that I couldn't reattach the line until I increased the diameter of that clamp back in the pits.!) That's where the fuel shutoff valve came in handy. The down side of that is that you can start, run, stage, and make it halfway down the track with the fuel valve shut off. The fuel bowls will use up almost every drop before you get the warning that somebody forgot to turn the fuel on. (Another reason that I'm not trying to be a crew chief. That person will be blamed for almost all those fun lessons on how to lose - even without an opponent!
) It's getting time to hear that motor! A short video clip with sound will cause international spring fever!
JW