Can't get bike running right!!

It sat for months.
No fluid moving through the breathing system.
To compliment the previous notations on jets and passages getting clogged it may be that your carbs, after sitting for a long period has had its gaskets and seals dry out and contract.
This allows air leaks. No matter how small, those tiny air leaks will screw up your starting efforts as well as a decent idle/run condition.

Did you try spraying any carb cleaner mist around the carb connections while running? If there are leak issues you will hear the surge,

I had the exact same symptoms as you describe. Popping and snapping, surging and chugging, and then it just quit.
My plugs looked exactly as you described yours.
This sudden change in running condition was my fault.
I don't ride in hot weather. I let it sit, always intending to do a quick warm up but never followed through.

After it decided to barely run, and like crap when it did run, with a lot of WTF's from my end....I went through the bad gas/clogged fuel taps scenario and it did not change a thing.
I pulled both carbs. Two fasteners were not as tight as they should have been during disassembly. Before the bench I had cleared the passages, no clogs found, no change . I then pulled them both and disassembled them on the bench. Next, I put them in the ultrasonic cleaning gizmo. After that was completed I renewed and/or resealed all the gaskets including the intake Bakelite insulating gaskets between the head and intake manifold. I then properly tightened all the fasteners.
After completing reassembly/refitting to the engine, it fired on the first turn over and idled/ran as well as the last ride I took before weather came into play.
The seemingly out of nowhere problems can be frustrating. Too often I over-analyze. Most often its a fairly straight forward answer.
 
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Schwany said:
Coil circuit resistance range: 3.0 to 5.0 Ohms (3.0 absolute minimum)
Click to expand...
According to Trispark trouble shooting guide for their latest twin stator unit, two 6v coils should have primary resistance of 1.8-2.2 Ohm:
Can't get bike running right!!



The range you state is for the single coil dual output I believe.

Link to guide:
 
kommando said:
Ethanol does the same blocking of small jets on all carburettors, my Keihin carb on my KLF300 and my Briggs carbs all need their pilot jet probing for clean starting every one or two years.
Click to expand...

I haven't experienced that problem, but I drain and refill my float bowls as well as start my engine a few times a month. I also use Sta-Bil in the fuel. I don't have 10 bikes in the garage anymore, so it is a lot easier to maintain 1 with pump gas in the tank.
 
Tornado said:
According to Trispark trouble shooting guide for their latest twin stator unit, two 6v coils should have primary resistance of 1.8-2.2 Ohm:
Click to expand...
Could you post a bigger image? I can barely see that. :rolleyes:

I cut and pasted the text right out of the Specifications page in the pdf of the TriSpark manual for the 0006. There is no mention of that spec being specifically for dual output coils, but it would not surprise me if it was omitted by mistake.
 
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Tornado said:
Didnt mention year of bike, glass fibre/resin tank perhaps? Modern fuel will dissolve resin in such tanks. Leading fouled carb jets and even accumulated build up on intake valves. You did mention one side lower compression, and a sooty plug.
Click to expand...
It's a 1973, 750. Metal tank.
 
Schwany said:
Could you post a bigger image? I can barely see that. :rolleyes:

I cut and pasted the text right out of the Specifications page in the pdf of the TriSpark manual for the 0006. There is no mention of that spec being specifically for dual output coils, but it would not surprise me if it was omitted by mistake.
Click to expand...
Its a screen shot off my phone, and text is actually smaller than the post comment text, when veiwed on my phone. Are you using a computer screen?
 
Tornado said:
Its a screen shot off my phone, and text is actually smaller than the post comment text, when veiwed on my phone. Are you using a computer screen?
Click to expand...
I'm kidding. Should have used a smiley face.

Yes, On a computer. I am incapable of using a phone for browsing.

I gotta get off this damn computer. Wasting time I am.
 
Tornado said:
Then trispark install guide and specs on their 6v coil sheet are wrong.
Click to expand...
No, there is some conflicting info but the resistance seen by the device must be between 3 and 5 ohms.

This: https://www.trispark.com.au/6-volt-ignition-coils says that the current 6v coils are 2.2 ohms so 4.4 total.

This is from the current twins manual:

Can't get bike running right!!


Generally, two Lucas original coils are 1.6 ohms so 3.2

If you use a dual-fire coil that is below 3.0 ohms, you will destroy the unit.
 
marshg246 said:
No, there is some conflicting info but the resistance seen by the device must be between 3 and 5 ohms.

This: https://www.trispark.com.au/6-volt-ignition-coils says that the current 6v coils are 2.2 ohms so 4.4 total.

This is from the current twins manual:

View attachment 116380

Generally, two Lucas original coils are 1.6 ohms so 3.2

If you use a dual-fire coil that is below 3.0 ohms, you will destroy the unit.
Click to expand...
And that is why trispark says two single 6v coils...each 1.8 to 2.2 ohms in series. Or one, 12v dual output at 3.6 ohm
 
When I was using the 0005B TriSpark ignition I had a 4.4 ohm dual coil which is within the 3 to 5 Ohm spec theoretically. The 3.6 Ohm reference in the Troubleshooting guide is the TriSpark coil which I think is the only reason they use it as an example. I'm using a Harley style 3 Ohm dual coil now with a new 0006 TriSpark and it works well. I think it is closer to 3.2 Ohm when measured with a DVM. Regardless the spark is definitely better. Not exactly the same coil cNw sells, but looks the same and has the same spec.

The old Norton ran well with a pair of 12V coils when using the Boyer ignition. I guess those would have killed the TriSpark, but I installed the dual coil to make more room for Keihin FCRs. Blah blah blah who cares.

Out of spec coils might work for a couple of years, but may be slowly damaging the ignition if it turns out to be the ignition causing the misfires and stalls. Change ignition or coils would be another troubleshooting step worth looking into. Well, it would be for me anyway. I swim against the current a lot though. I could also be repeating myself and unaware of it. :)
 
Schwany said:
TriSpark ignition is finicky.

So what are you using with your TriSpark ignition?
Click to expand...
I have a trispark on my velo 500 single, running the trispark single 12v coil. On Commando i run VapeWassell ei with two 6v coils connected in series (original Lucas). They are whatever the spec is as listed in workshop manual.
 
I have a pair of 6v Lucas coils, the exact same ones that TriSpark sells along with their own coils and which the state are compatible with the Tri-Spark ignition. Unless my multimeter is totally whacko, each reads 2.8 ohms or a total of 5.6 ohms for the pair. This reading is above the citation in the TriSpark Install manual which calls for 3.0-5.0 ohms, or 1.8-2.2 ohms for their own coils or 3.6-4.4 ohms for the pair. So, what is correct.
 
lazyeye6 said:
I have a pair of 6v Lucas coils, the exact same ones that TriSpark sells along with their own coils and which the state are compatible with the Tri-Spark ignition. Unless my multimeter is totally whacko, each reads 2.8 ohms or a total of 5.6 ohms for the pair. This reading is above the citation in the TriSpark Install manual which calls for 3.0-5.0 ohms, or 1.8-2.2 ohms for their own coils or 3.6-4.4 ohms for the pair. So, what is correct.
Click to expand...
Seems your coils are a little too high on primary resistance...should be closer to spec range 1.8-2.2 ohm
Meter leads at fault perhaps?

I would think having coil at higher resistance would only mean you'd get a less powerful spark...too low a resistance would potentially mean mote amperage coming through the ei, which could lead to burn out?
 
lazyeye6 said:
I have a pair of 6v Lucas coils, the exact same ones that TriSpark sells along with their own coils and which the state are compatible with the Tri-Spark ignition. Unless my multimeter is totally whacko, each reads 2.8 ohms or a total of 5.6 ohms for the pair. This reading is above the citation in the TriSpark Install manual which calls for 3.0-5.0 ohms, or 1.8-2.2 ohms for their own coils or 3.6-4.4 ohms for the pair. So, what is correct.
Click to expand...
I have measured MANY original Lucas coils with a professional ohmmeter. They are 1.6 ohms. The Tri-Spark coils are made the same way but are not identical and when I measured them, they were 1.8 ohms. I have written to ask why the link I gave states 2.2 ohms.

Any way you look at it. If you use 6V two coils in series or one 12v coil. The total resistance must be between 3.0 and 5.0 ohms. Below 3.0 ohms and you'll burn out the output transistor. Above 5.0 ohms it will not fire or if it does will not fire correctly.

I normally use original Lucas 6v coils or new Lucas 6v coils. I always check them. If lower than 1.6 ohms, they are put in the recycle bin. I don't want to be on the bleeding edge. When I use a 12v dual-fire coil, I use the Drag Specialties 4.0 ohm coil part number 2102-0276
 
I always approach things systematically. My bike has Boyer ignition with a double-ended coil from a CB750 Honda - wasted spark. When you have separate coils, you have more connections to check, some can develop high resistance or loosen. If I have fuel and spark, the bike must start with the throttles closed and enrichener open. But I do not use pump petrol as fuel - and I always drain the carbs after use.
With twin coils, you might have twice as many problems. I have seen those twin coils on Commandos -I would not do that. Like a lot of things on British bikes, they are a bodge-job. When you set up the ignition timing with a double-ended coil, you are only dealing with ONE connection.
I have always loved British motorcycles, but I know what to expect.
 
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