O K, now that I got that figured

[Guest]

After putting the bike back together last week and it not running, I could get it to sputter. I took the carbs off and did a complete overhaul and double checked the valve shims, #3 exhaust was at 10 mm so I had to get me a bigger shim, now they are all within spec...So the carbs are perfect and valves and Electrical? The electrical has to be good, I put new coils on and new wires and new boots...So, I go to start it and same bloody thing, sputtering...So, I pulled the bike back into the garage and closed the door, took out the spark plugs, grounded them, then I noticed that one coil is not working...Could one be bad, new? Should I go back to the old coils/original?

[tom203]

And why is one coil not working ? no signal from ignitor, no power from kill switch?? coils are easy to test- see step 10 in this link

http://members.dslextreme.com/users/storagecliff/images/electrical_odd-n-ends.html#A17

[spyug]

I have it on authority from a professional bike mechanic of over 30 years in the trade that coils seldom go bad. It is usually bad wires or more likely bad plug caps. It could also be, as Tom says a faulty ignitor. I, myself, have had a couple of coils that I thought were dead only to find them fine with new plug caps.

Follow his suggestion and see what you get. You could also pull the plug caps and see if you can get a spark from the end of the wire (you may need to trim it a bit and perhaps stick in a small nail or tack) grounded to the engine.

Let us know what you find.

[jknappsax]

Coils DO go bad!

I just had an Accel coil that the primary opened up. Read across the primary terminals, and you should see about 3-5 ohms. If it reads open, it's bad.

[Meriban]

I found, much to my chagrin, that the one of the wires that go to the coil was grounding on the frame...I took the coil out of it's mounting and held it clear, then I took the plugs out one by one and grounded them...Sure enough, sparks came from both plugs wires...That was a mystery...Now I got fire all around...I went and bought new plugs for it and will install them tomorrow and see if she fires up...