ImDoingMyBest
CB750 Member
I’ve done just about everything at least twice at this point and I’m pulling my hair out trying to figure it out. The Kreme in my gas tank started coming off so rust got into my carb. Was running very well until that happened, and after it would run okay until something would get lodged in the carb and it would die, then I could get it running a few miles before it happened again. Fast forward to now, the bike seems to hesitate occasionally at idle, dies or hesitates when giving gas at idle, accelerates fine after 1200k RPM and prefers a little choke, all while stationary. Mixture screws seem to have little to no effect on idle. All the way in kills it, adjusting by half turns barely changes idle (doing half since 1/8 didn’t do anything). Adjusting gets the bike to a semi steady idle or kills it but no “fastest idle” circumstance. Went for a ride to get gas, it hesitated while accelerating, low power, backfired, stalled twice while just trying to go from a stop, and sounded almost like it was running only on a few cylinders on the way back? Occasionally sounds like it’s running on a few cylinders, but only after warming up and usually after riding for a bit before it stalls. Before I tried synching the carbs, it would start and ride, but hesitate and stutter past 5k RPM and hesitate at idle, lowish power throughout the range. I made it 30 mins away no problem, on the way back on the highway, same way I came, after going 75+ for a mile or so giving gas did nothing and it stalled as soon as I slowed down. Had to wait a bit before it would kick over again and then die a few miles down the road.
Here’s what I’ve done so far:
- cleaned the carbs in an ultrasonic too many times to count, including all jets and poked the holes with a small wire and sprayed cleaner through every orifice. Main jets, idle jets, accelerator jets, everything
- synced the carbs
- checked for vacuum leaks (no change to RPM when sprayed with cleaner)
- checked spark plugs, they’re sparky but seem to have caked on dielectric grease
- gas I’ve been using has been refreshed a few times, originally had sea foam in it, now has startron mixed in instead
- running petcock filter and in line paper filter too, checked and carbs are getting fuel
I haven’t checked air filter yet, I’ll probably do that next. last time I looked at it it was basically new but it’s been a while. (Running stock air box, Keihin carbs)
Any advice would be greatly appreciated, I’ve been at this rodeo since August and I’m going insane


Here’s what I’ve done so far:
- cleaned the carbs in an ultrasonic too many times to count, including all jets and poked the holes with a small wire and sprayed cleaner through every orifice. Main jets, idle jets, accelerator jets, everything
- synced the carbs
- checked for vacuum leaks (no change to RPM when sprayed with cleaner)
- checked spark plugs, they’re sparky but seem to have caked on dielectric grease
- gas I’ve been using has been refreshed a few times, originally had sea foam in it, now has startron mixed in instead
- running petcock filter and in line paper filter too, checked and carbs are getting fuel
I haven’t checked air filter yet, I’ll probably do that next. last time I looked at it it was basically new but it’s been a while. (Running stock air box, Keihin carbs)
Any advice would be greatly appreciated, I’ve been at this rodeo since August and I’m going insane


