im hoping hightower can help me with this. i took my bike to a dyno to get it dialed in. it made nice numbers with 54 hp and 49 ft/lbs of torque. they told me i had a bad lean spot in the low rpms but they were able to adjust it out with the accelator pump. when i looked at the carb tonight the pump screw on the top of the carb is backed out to the point that it does not even touch the plastic peice at any time throught the throttle travel. does this seem right? the screw sticks out the top of the carb close to a 1/4 of an inch. i havent riden it yet but sitting there idleing if i wack the throttle i get a bog and my egt drops to like 500 degrees. if i had to guess i think the piolt is to small and the over compensated for it with the pump. any opinons? my set up is 12.5:1 piston, hpr cams, ported intake, hmf exhaust, vortex ignition, and cmf air box. my tm 45 has a 160 main 37.5 piolt and 97 needle second from the top. pump is activated with 50 jet. any help? by the way on the dyno the hp and toqure cure were nice and stright across as well as the air fuel. in the first runs i could see the lean spot but after they adjusted the pump the a/f looking mint nice and stright at 15.1

 

TTT

 

anyone?

 

look at this picture TM45 pumper parts identification

The squirt start screw should be set to allow squirt immediately off idle, this screw is almost useless really, some people just remove it. but the squirt stop screw - the skinny one on the top of the carb - otta be set to stop the squirt by half throttle. some people have it set to squirt til 3/4 throttle, but I do alot of throttle feathering climbing hills and stuff at this range, and the constant squirting going back and forth with the throttle just gives too much fuel when not needed.

if I had to guess, I'd say the dyno guy has your carb pumper set with too much delay on the squirt, check the squirt start screw and make sure it is backed out to allow squirt immediately off idle, this is normally where stumble occurs. the stop screw, being backed out 1/4" above the carb cap, sounds like way too long a duration to me, i'd tone it back to stop squriting sooner.

your jetting is almost the same as mine, with very similiar mods. I do not think your pilot is lean.

 

THE ONLY THING THAT HAS ME CO0NCERND IS THE LEAN SPOT IN THE FIRSR DYNO RUNS THAT DISAPPERED AFTER THE PUMP SCREW WAS BACKED OUT. I GUESS I NEED TO GO OUT AN RIDE IT AND SEE WHAT HAPPENS. THANKS HIGHTOWER