left is dead at idle

i got the 79 750 twin and the left side isnt firing at idle, but when u give it some gas at about 4-5000, it comes to life. or when your runnin low rpms and fire down on it, itll go then but both never fire inder 1500. im thinkin a weak coil, can anyone else confirm

maybe check that your carbs are sync'd, perhaps the left one is closed at lower throttle settings? I would think a bad coil would work at idle and cutout as the load increased but sometimes coils do strange things. good luck

they arent that bad if so because it gets better as it warms up

If not already done, would:

Perform compression test;

Check and assure valve clearances to specs;

Visually observe brand new plugs for quality fat blue spark;

Assure ignition timing is correct;

Assure advancer is properly functioning;

Check for voltage leaks in old hard worn-out plug wires (may spray water mist over coil and plug wires with engine running in a dark garage);

Assure air filter(s) clean, clear, unobstructed, and not over-oiled (if applicable);

Lastly, clean carb pilot circuits.

Good Fortune!

It can't be the coil because the same coil fires both plugs on a twin. Clean fuel system, sync carbs and make sure the pilot jets and passages are clear.

Valve/compression check always a good idea.

If you do want to change the coil, Z1 sells an EMGO 4 Ohm replacement for $36. That's what I am running on my '79 750 twin.