Hi and thanks for reading. I have a 2000 ultra classic big sucker air cleaner with cobra speedsters. 2014 I rode to myrtle beach for the spring rally 3 1/2 hours bike ran flawlessly on the way home 2 hours in I pulled in clutch at stop light and bike died, fired back up but acted as if it were running on 1 cylinder unless I feathered throttle, it accelerated close to normal not quite as snappy as normal. I stopped got gas, fired up and seemed ok. rode about 15 miles and at stop light it died again. I made it home by feathering throttle any time I had to stop. I tried trouble shooting in drive way but after I got home and unloaded it ran fine. next day went for a ride about a mile in it died at stop I checked for spark at both cylinders all looked good.Charged battery on tender and problem didn't show up again for a couple of weeks. 1o mile ride it acted up again. I cleaned the small hole on the face plate of the throttle body, idle went up and seemed ok again. I don't see any holes in any of the fuel lines, bike is not as crisp as it should be and will stall at stop. stopping for short time seems to fix it for a few miles then it happens again. almost like there is a vacuum not letting it breath. any questions or suggestions? thanks again.I have fuel tank off now a few spec of trash in bottom of tank all else looks fine. bike does seem to be running hotter than normal

 

just behind the air filter bracket, at the front of the throttle body, there may be a vent tube about 1" tall that would have a rubber vent plug cap on it. (I don't know about 2000 models). Sometimes a backfire through the intake will blow that cap off causing vacuum problems. I wouldnt take a second to check it. No need to disassemble anything.

 

thank you, I had the breather backing plate off today and yes the black cap is in place but tomorrow I will double check for integrity

 

that looks good I took her for a ride 10 miles and started acting up seems that I get 55 or higher for any distance and it want to act up. turn ignition off for 30 seconds and she cranks back up and runs good, I went 6-7 miles after restart at 45 and she ran fine got home and it set on drive idling perfect

 

ohm tested engine temp sensor and it checked out good

 

rear cylinder seems hotter than normal. and it seems to take a 2 mile 55 plus ride to get it to act up. I can ride around town and it run flawlessly

 

Possibly a restricted exhaust. Seen it many time on autos with the same symptoms.

 

that is a thought I will check it and see thanks I pulled plugs they look good front seemed a little lighter than the rear

 

I now can add I do believe she is running hot, This time it acted up just riding around town and continued till i got home I checked temp at bottom of rocker box cover 309 rear cylinder and 286 front. it felt hotter than normal. I added some sea foam to the tank to see if it would clean injectors, other than lean condition or oiling condition anything else make her run hot ?

 

Have you ever replaced the fuel filter?
It will allow the bike to run ok until you ask it to accelerate through the rpms, then runs lean until it has a chance to catch up when the rpms and load is reduced or the bike is shut off then restarted.
Bob