- Joined
- Nov 11, 2012
- Messages
- 394
What jetting is mostly used for the VM34 single conversion for the Atlas? I've been ordering a lot of jets (pilot, main, needle jet/needle, slide) trying to get rid of a stumble at 1/8 to 1/4 throttle and find some sort of adjustment on the air screw. Right now I have:
Pilot: 35
Main: 250
Needle Jet: P-0
Needle: 6DH3 (clip down one slot)
Slide: 3.0
Air Screw: Between 1 1/2 and 1 3/4 turns out
I'm running rich at idle which I'm fine with to eliminate slow speed lean surging, cracking the throttle is crisp with a quick return to about 1200 RPM a slight hang and back to ~1000. The dead spot was in the 3000-3500 RPM range (between 1/8 and 1/4 throttle) which improved the best with the above jetting. The bike seemed to run a little better with the needle clip in the middle but the plugs were really white, lowering the clip brought the right plug some nice brown color, the left is running a little lean with a hint of white. Not sure if that is due to a timing issue or what, but when I had a richer (6DH4) needle the opposite was true (left was richer and right was leaner?????). The bike runs really well and I'm much more pleased but I feel it can be better. I don't know of any tuning dynos around so I'm trying to go off feel and performance and what ever a plug can tell me (I've been going through them a lot testing jetting combos). My goal is to have a good mixture at cruising speed (1/8 to 1/4 throttle in 4th gear). I'm really tempted to trash the Mikuni and go with Amal's but I have read people really love them on the Commando.
Any other tips with this carb is welcomed and let me know what jets you use and what your plugs look like.
I need to give a shout-out to the guys at Sudco in California, they've been really cool in helping me get this thing figured out.
Scott
Pilot: 35
Main: 250
Needle Jet: P-0
Needle: 6DH3 (clip down one slot)
Slide: 3.0
Air Screw: Between 1 1/2 and 1 3/4 turns out
I'm running rich at idle which I'm fine with to eliminate slow speed lean surging, cracking the throttle is crisp with a quick return to about 1200 RPM a slight hang and back to ~1000. The dead spot was in the 3000-3500 RPM range (between 1/8 and 1/4 throttle) which improved the best with the above jetting. The bike seemed to run a little better with the needle clip in the middle but the plugs were really white, lowering the clip brought the right plug some nice brown color, the left is running a little lean with a hint of white. Not sure if that is due to a timing issue or what, but when I had a richer (6DH4) needle the opposite was true (left was richer and right was leaner?????). The bike runs really well and I'm much more pleased but I feel it can be better. I don't know of any tuning dynos around so I'm trying to go off feel and performance and what ever a plug can tell me (I've been going through them a lot testing jetting combos). My goal is to have a good mixture at cruising speed (1/8 to 1/4 throttle in 4th gear). I'm really tempted to trash the Mikuni and go with Amal's but I have read people really love them on the Commando.
Any other tips with this carb is welcomed and let me know what jets you use and what your plugs look like.
I need to give a shout-out to the guys at Sudco in California, they've been really cool in helping me get this thing figured out.
Scott
