73 CB350 twin HELP!


New Member
Hello all I’m new to this forum but been around motorcycles for awhile. Mainly vintage Harleys. I helped a buddy out by freshening up his cb350. New head gasket , Rec regulator combo, new boots and seals for mikuni, electronic ignition with timing set correctly. New coils,plugs and wires. Valves set to spec, new battery. Charges at 14v revved. I’ve done the yellow wire mod to get better charging. Bike fires up no problem idles great. Runs down the road decent but Boggs out at wide open. It’s running mikuni vm30s with reverse cone pipes and pods. I’ve tried a ton of jetting combos. Right now I’m at 100 main and a 20 slow. needle jet bleed style 176 p8, slide 2.5 , needle 6f5. Clip in middle setting. .5 air jet. Floats are set to spec as well. I live in the south and I’m at sea level. I’ve sprayed around seals and head so no leaks. Plugs seem a bit dark and I feel as though I’m getting to much gas. Can I get some help or tips ?
Last edited:


Over 1,000 Posts
main is probably way to small

150 mains, 6F4's in the richest clip positions, #176 P-6 needle jets, 25 pilots, 0.5 air jets, 2.5 slide cutaways. air/fuel mixture screws are set 2 turns out
was what i ran on my cb350 it ran almost perfect just needed i think a better needle but was so close to perfect you had to be fussy to detect it but i could see it on the dyno

i switched to baby 28s at this point in the journey

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