B@S oppy help

i say a post on this before, cant find it now, but i got a twin that runs on one cylinder. the other one will some times fire, ive switched plugs, and done some testing with disconnecting the boots. so what i found is the RC (right cylinder) does not fire. now, i get it running, and some times i can take the boot of the RC, and nothing changes, but some other times, the whole engine will die. and the LC will always kill it. its obvious its not firing on the RC SOMETIMES. some times i will adjust it to run rich, and when i rev it, i get black smoke out both sides, or when at full throttle, it will some times run smooth, and sometimes not as smooth. it is the magneto right? i read that they do that sometimes?

The magneto fires EVERY revolution, and sends spark to both plugs. Therefore, each cylinder gets spark on both the compression and exhaust cycles. If one is getting intermittent spark, most likely candidate is a bad plug wire.

If not the wires or plugs, check compression on intermittent cylinder and see if a valve is leaking or hanging.

it gets good compression on both cylinders, by hand that is, i don't have a tester. ill check the wire thought, if i dont find any thing, i will swap a mags between my fun motor and this new work motor.

Inspect the insulation very carefully. If any cracks are found, wrap wire with 2-3 layers of electrical tape. That will buy another season or two of use.

thx

nothing wrong with wires, the mag was a bit rusty thought, here is the new thing i found, when running at idle, i runs on left cylinder, if i disconnect ether spark wires from plugs, the engine dies. if i fully choke it at idle, it starts to die, then it starts running on the left cylinder. (rather nicely) if i adjust the jet to run rich, it runs on left, lean, on right. at full throttle, it will sometimes run on both. i checked the manifold and valve, it opens what would seen to be a good amount to run fine. WTF! could i be the carburetor?

Buy new plugs and go from there. I suspect it is still a ignition problem, coil might be bad

I'd say replace the plugs w/ champion RJ19LM, if you find a damaged plug wire NGK makes a plug wire splicer for around 9 bucks I believe, but at that point you need more plug wire and a boot so it may be cheaper to replace the coil if you don't have wire and a boot lying around. The splicer works well, I used it on a snowmobile and it still works great.

New coil: http://www.amazon.com/Oregon-33-345-Ignition-Replacement-Stratton/dp/B0009XHKDS/ref=sr_1_1?ie=UTF8&qid=1426616985&sr=8-1&keywords=394891

NGK plug wire splice: http://www.amazon.com/NGK-J-1-Racing-Cable-Splicer/dp/B0018JXIXI/ref=sr_1_1?ie=UTF8&qid=1426616913&sr=8-1&keywords=ngk+plug+wire+splicer

It might be worth inspecting (replacing?) your intake manifold gaskets. A vac leak could cause similar mayhem.

Doc Sprocket wrote:

It might be worth inspecting (replacing?) your intake manifold gaskets. A vac leak could cause similar mayhem.

A little rtv silicone would do the trick.

While everything that has already been mentioned is right, when we had intermittent misfire issues like you described it was a coil replacement and new plugs that saved the day.

YOU GOT IT DOC!! it was awhile ago, and IDK why i did nit reply earlier, but it was the gaskets.