- Joined
- Oct 28, 2009
- Messages
- 1,198
I'm trying to sort out my 72 Commando for the ride to the INOA rally in Elma.
The bike starts fine, idles, and runs well at low to mid-range rpm. Until I get into the 2/3 throttle range and above. At that point the engine stumbles badly, and if I twist the throttle all the way open, the engine loses all power and de-accelerates. If I back off the throttle from full, it stumbles again, and if I back it off more, the engine starts pulling strongly.
What the hell is going on here?
The carb is clean. Slides and jets are all correct and in good nick (new needles, needle jets, slides). I tried moving the needle down, then back to the middle position: no difference. It had 200 main jets, which I switched to 220 main jet, no difference. If I turn the choke on, it doesn't change the stumbling or power loss.
I am starting to think the problem is electrical, not carburation. I am going to try swapping the boyer box, and coils.
Any thoughts???
Stephen Hill
The bike starts fine, idles, and runs well at low to mid-range rpm. Until I get into the 2/3 throttle range and above. At that point the engine stumbles badly, and if I twist the throttle all the way open, the engine loses all power and de-accelerates. If I back off the throttle from full, it stumbles again, and if I back it off more, the engine starts pulling strongly.
What the hell is going on here?
The carb is clean. Slides and jets are all correct and in good nick (new needles, needle jets, slides). I tried moving the needle down, then back to the middle position: no difference. It had 200 main jets, which I switched to 220 main jet, no difference. If I turn the choke on, it doesn't change the stumbling or power loss.
I am starting to think the problem is electrical, not carburation. I am going to try swapping the boyer box, and coils.
Any thoughts???
Stephen Hill