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Sibbo, I too would like more information to work with. I've got a related question or two of my own.

Was your bike starting and running just fine before the dual plug conversion? And did things go to hell immediately upon the dual plug conversion and corresponding ignition changes?

You haven't actually looked to see if all 4 plugs are sparking, whether in the original coil arrangement or the revised one have you?

What about returning your bike to the original two plug electrical configuration? The two plugs on the bottom of the heads can just go ahead for the ride. If the bike suddenly runs fine then I would suggest moving the plug wires to the bottom two plugs and retesting.

Lastly, it won't mean too much to me, it might to others here. What ignition amplifier/ignition control unit and what coils are you working with?


Ken

I have a feeling that there was a fairly esoteric discussion, with Fun involved on the subject of coils, way beyond my pay grade!

What ignition system are you using? Is is stock, stock with modified spark advance, or one of the aftermarket electronic ignition systems, such as Boyer,Dyna etc etc? This info could help us help you charles

I'm afraid I'm not going to be much help.The ignition system is standard ,to the best of my knowledge , the coils are ex Japanese multis ( the normal way in Oz ) .She was twin plugs before I bought her so no comparison .

Sibbo, did Michael in Nimbin work on your bike?

He did once and got her running well but the starting difficult remained , the fella in the motorcycle shop in town changed the coil wiring around .He's had a fair bit of experience with Beems .I would have taken it to Michael but getting back without wheels the back down again is hard from here .

Sibbo wrote:I'm afraid I'm not going to be much help.The ignition system is standard ,to the best of my knowledge , the coils are ex Japanese multis ( the normal way in Oz ) .She was twin plugs before I bought her so no comparison .

Sibbo, since there is so little you can tell us, it strikes me that your best option would be to go back to the stock setup, that is one plug per cylinder. You would buy a stock coil, which on your ST is probably a single twin fire coil. It is a known entity. Just because you have two plugs per cylinder doesn't mean you have to fire both of them. Simply run one plug wire to the top plug on the left cylinder and the other plug wire to the top plug on the right cylinder. Set the timing to stock and see what you have.

Thousands of ST's in the world run just fine with only one plug per cylinder.

Now, if the bike still acts up you can look to other places than the coils for your problem. And if there is still a problem you can get meaningful advice from the people here because they know what you have. Other possible problem areas include the ignition module, the carbs, valve clearances, air leaks, or who knows what?


Ken

I'm with Ken.
At the worst Sibbo, ya got twin plugged heads.
Well, maybe worse if you have to spend coin to go stock.

You can always bang sumpin in the spare holes to inflate your camp mattress.