right cylinder only fires part of the time.coil or what?

conner

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hey guys i have a 74 hardtail boober and i was curious if there was anybody who could help me with my firing problem. im thinking it might be the electrical going on with my coil or i think it might be how i have my carb set up. i have a ss super shorty carb with a custom fabbed pipe the mounts to both ports, the reason i think it might be my set up is because my carb is on the left side and the pipe to my right cylinder is longer.
i know that my cylinder is getting gas though because my plug will be wet and black from not firing correctly. any advice or ideas would be greatly appreciated!
 
The cylinders alternate their intake strokes. The carb, in theory is working twice as fast as either dual carb would be. I doubt that fuel is the problem, since one side works fine.

What I would do, is swap, one at a time, your plugs, your plug wires, and your coil terminals. If the problem switches sides, you found your culprit.

The other possibility, though this is less likely, IMO, is compression. Check your valves. Check compression.
 
I switched coils around and replaced both plugs and wires, the same thing is happening, i checked my compresion and my right side is 120 and my left is 125.
 
That's a bit low for both, but the 5psi disparity shouldn't make much difference. Check your valve adjustments.
 
You might have one condenser crapping out. Swap the condenser connections between points sets and see if the problem changes sides.
 
Are you running the old OEM type ignition coils? If so, they are giving you a very weak spark. Toss out those coils and buy yourself a new single, dual output, ignition coil.

If you stay with points, you are limited to coils with 4 ohms or larger primary resistance. If you change over to a Pamco (replaces the points), you can use coils from 2.5 to 4.5 ohms primary resistance.
 
Those old OEM coils only had 12k to 13 k volts when new. New dual output coils can give you 30K to 50K or more volts.

You can use a single, dual output coil, with points, simply by connecting both sets of points in parallel. Mikesxs sells coil # 17-6822 which has 4.5 ohms primary.

Another way, is to use an Accel #140403S ( 3.3 ohm primary) with points. To do this you would also need a 1.3 ohm ballast resistor.

The best solution, is to change over to a Pamco, which gives many more choices of coils.
 
"Low compression and weak spark = poorly running engine. "


I can vouch for this. Not what you want to hear, but its true.
 
Ive been tearing through my bike and i just powder coated my frame and forks so until next paycheck i guess ill order some stock coils and condensers
 
What part about the stock coils being no good didn't you get? They're under-powered and weak even when new. You'll be living paycheck to paycheck for the rest of your life if you continue spending money foolishly like this.
 
I see you've chosen to use your 9th post on this forum to tell a senior member, with huge amounts of experience with these machines to "gtfo". Nice work. We will all certainly be very willing to use our experience and take our time to help you in the future, given your reaction to his and others' sage advice.

5twins was not "being an ass." He was asking a legitimate question. Why do you want to keep the weak, stock coil design, when there are better, much cheaper options out there?

I suppose the following question will make me an ass as well. At least I will be in good company.

Why are you bothering to powdercoat the frame and forks of a bike that doesnt run? it sounds like your engine needs at least the top end rebuilt before it will be reliable. While you are "going through" your bike, you might consider the heart before the makeup. Some people find this advice works in social situations as well.

Best of luck in your future ventures.
 
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I am with you Firerunner - so come on, conner, play the game. You're welcome in the Forum, but we look after each other here, we talk bikes and some other stuff, and enjoy the company of like-minded people.

Anlaf
 
Yeah this conner guy is not real clever with math!

He says he may buy 2 original type replacement coils (#17-6805) , so cost of the 2 coils would be $53.90.

Another choice would be to buy one coil, the #17-6822 ,and spend only $37.95.
 
I just read that link, TwoMany - it seems that function is often sacrificed for style. It's fine when it looks good, too (and some of the guys are really very good at the artwork by the look of their bikes, but the point for me is to ride and keep it going. Even so, there always seems to be a way to make stuff work no matter how arty - there is a lot of experience among the guys. Maybe one day I'll get the time to decorate my bikes and have a 2 into 1 carb manifold that wraps around the handlebars of something.

Anlaf
 
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