Motorcycle Repair: 73 xlch wont take throtle, air fuel mixture, intermediate jet

Question
QUESTION: hi, hope you can help .  First i have a 73 xlch that i rebuilt this year.  the flywheels were professionally redone, new weisco .020 over pistons, machined jugs, redone valve seats and new kibble white valves, everything went smoothly on rebuild and fired up on third kick.  idles great starts great and goes down the road great until i try to give it any more throttle than a little, and once i hit 45mph it doesn't want to go any more.  When i try to give it moderate to hard throttle or go past 45mph it backfire in exhaust and pops like crazy.  i have taken apart my s&s super e carb and i have a 028 intermediate and a 066 main jet  all passageways are clearand i have tried every combo of turns on excel pump screw and adjustment screw to no avail.  the plugs look a little sooty but the grounded electrode looks tan  timing seems ok even though it is hard to see through my plastic plug.  any help would be great.  i was thinking the inter jet was too small but am not sure  thanks in advance

ANSWER: It sounds like you have carb problem. Lets start at the begining. Start the bike and let it warm up. The air/fuel mixture should be slowly turned inward, just until the bike starts to stumble. then back out about 1/4 of a turn. Now its set. Adjust the pumper, so its turned off. Take the bike for a ride. Dont go over 2500 RPM. If the bike bogs down, then the intermediate jet is to big. If it spits through the carb its to small. Every time you make a jet change, readjust the air/fuel mixture screw, like above. Next, check the main jet. Take the bike for a ride, but go over 3000-3500 RPM. Look for the same as you were looking for int he intermediate jet. Once the jets are done, now set the pumper. Open it about 1 1/2 turn and go for a ride. ride like you normally would. If the bike bogs, like not enough gas, then open the pumper about 1/4 of a turn. Keep doing this until you have it set. what youa re looking for is the bike not bogging between gears, but have it closed as far as possible so you dont waste gas
Good luck and happy riding
Mike

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QUESTION: hi thanks for the help the only thing is that i don't have a tach so i don't know the rpm  it doesn't spit through carb but it stumbles and pops out exhaust on moderate to hard acceleration or if i go over 45mph i tried a 032 itermediate and 066 main with little change  sorry to bug you but i am getting frustrated  thanks again

ANSWER: On the RPMs, just estimate. If your going about 30 MPH you will be under the 2500 RPM. The 32 intermediate jet is a little big for your bike.
One question, are you running points or electronic ignition? Also, after your ride, pull the plugs and let me know what color they are
Mike

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QUESTION: yes the 32 is big but thought i would try something bigger than the 028 to see what happened  and got no change  so, with the 28 jet the plugs are a tan color on tip with a little black around lip of plug so am going back to that, sound right?  i am running points  to me it just doesn't seem to be advancing corectly but the advance mechanisum is new and seems fine  but when i put the timing light on the bike the advance mark won't stay in the hole 100% of the time now and again it jumps out of hole   especially at higher rpm no matter if i try to adjust points backing plate to try and keep it there.   thanks again for your help

Answer
Your plugs are fine with the 28 jet. Couple of things to check. Check the points to make sure they are gapped right. I would change the condenser. If you have a weak condenser, it will not fire hot. Check your pushrods to make sure they are not to tight. If they are, one of the valves will not close all the way. Also, check to see if you have a intake leak.
Good luck and happy riding
Mike