Electronic Ignition + Battery + Cylinder

Before I write this, rest assured I've searched and read many of the other threads on this issue. Most those threads are 4-5 years old now, and I'm wondering if there's been any new developments in the systems.

My setup, 1973 Norton Commando 750 Roadster - serial number puts it into the limbo of "detuned" models of late '72 built / '73 released (still not sure what that really means in terms of differences of other 73's).

I purchased the bike 2 months ago, and at the time it was having difficulty kicking after sitting in the previous owner's garage for a year or more. I replaced the fuel and fuel lines, drained the oil and put it in fresh tank, charged the battery, and it kicked over right away. Lucky me!

A week later, replaced the tires and rear chain with help from a friend. Kicked over! A week after that, I took off the carbs to clean and sync, cleaned up and zip tied the other cables that had been taped to the frame. No kick! Nothing. Realized the battery had died, so recharged it and boom - kicking! But wouldn't hold idle, no matter the adjusting.

Had my friend help re-do the carbs, replace the throttle cable (too long), adjust the valve gaps and when buttoned back up it kicked! One hitch - it was only firing on one cylinder and shortly after died. Kicked again, same thing. Kicked again, and heard some pops. Then nothing. Tried again the next day, kicked for a minute then died. Tried kicking again another 10 mins, and nothing. Turned the key to off, and got a big backfire jolt (mind the engine wasn't running).

The last few days, I've tried kicking again and it fires on the single cylinder for a few then dies. Checked the plugs and swapped sides - still the same cylinder not firing. Checked the leads, swapped sides. Still one cylinder not firing.

Tested the battery voltage today. 12.7 when off. 12.1 when on with lights. Dips to 4.1 when I kick, then works its way back up slowly before the bike dies. It's a Duracell Ultra, three years old.

The bike came with an updated electronic ignition from the previous-previous owner - so I'm guessing it's about 5-10 years old. Can't tell who made it. See picture below if you're able to identify it.



My question is A.) What should I try next to determine the cylinder issue? B.) Could it be the battery causing the failed cylinder? C.) Could it be the electronic ignition failing? D.) Between TriSpark and Power Arc, which is proving to be most durable? E.) Should I try and try and buy Boyer and go back to original setup - is that even possible?

Thanks in-advance! I'm a novice at best - so the more detailed and basic the advice and instructions, the better. Only been riding 2 years, and my other bike was a 60's 2-stroke.

4.1 Volts? Seriously?

Try connecting your battery a known good battery, such as one in a car.

You have Lucas Rita ignition there probably the most reliable next to all the other electronic conversions,
It sounds like your pilot jets are blocked you will need to poke a wire through the jet
There is loads of info about doing this,carb cleaner won't work you need to poke them clear , they are behind the pilot screw and not very accessible, cheers

Ronnie said:

The bike came with an updated electronic ignition from the previous-previous owner - so I'm guessing it's about 5-10 years old.

Click to expand...

Probably more like 20-30 years old.

Ronnie said:

Can't tell who made it. See picture below if you're able to identify it.

Click to expand...

Lucas RITA as mentioned. There should be an 'amplifier 'box' fitted somewhere (on a rubber mounted plate between the coils?) marked 'AB11' (or AB5).

http://www.eurospares.com/lr100a.jpg
http://www.eurospares.com/lr100b.jpg

as a side note the rita does not play well with a dual output coil.

Maybe give us some history on the bike
If you have any? was it in regular use before? Or Rebuilt ? Etc
You really do need a good battery with a Lucas rita
You should have two 6volt coils
I'm assuming you have the original twin amal Carbs ?
If you could put some pictures up it may be easier to advise you
There's plenty of help on here ,Cheers

Thanks for the responses! I'll snap some more pics this evening and upload them.

The history of the bike is questionable, at best - I believe I am the 5th owner. The previous I owner I bought it from was the 3rd or 4th owner - he is unsure himself. He'd had it since about 2014, the owner before him had only had it a couple years. The previous owner to that had bought it off eBay from what may or may not have been the original owner in Texas. The electronic ignition was installed prior to the previous owner, and he isn't sure when.

The bike speedo shows ~6K miles on it, which is hard to believe or confirm. However, the local Norton club stopped by and took a look and based on all signs, they believe it could be original miles. It currently has the original twin Amal carbs. I believe both coils are 6 volt. I'll confirm tonight. I believe there is the amp box, and will snap pics tonight too.

Regarding the pilot jet, I'm pretty certain I'd cleared both well using a guitar string - but will do that again tonight to double-confirm.

One thing I should've also noted, the bike will not kick over without the choke on. This was the case from the very beginning, even in warm weather. I rode it out the second week I had it going, and anytime I attempted to turn the choke off after riding a bit and the bike would die.

Would it be wise to update the electric ignition system to something like the Power Arc from Old Britts, regardless? I've been reading plenty of good reviews, and their price for the whole kit is reasonable.

Ronnie said:

Thanks for the responses! I'll snap some more pics this evening and upload them.

The history of the bike is questionable, at best - I believe I am the 5th owner. The previous I owner I bought it from was the 3rd or 4th owner - he is unsure himself. He'd had it since about 2014, the owner before him had only had it a couple years. The previous owner to that had bought it off eBay from what may or may not have been the original owner in Texas. The electronic ignition was installed prior to the previous owner, and he isn't sure when.

The bike speedo shows ~6K miles on it, which is hard to believe or confirm. However, the local Norton club stopped by and took a look and based on all signs, they believe it could be original miles. It currently has the original twin Amal carbs. I believe both coils are 6 volt. I'll confirm tonight. I believe there is the amp box, and will snap pics tonight too.

Regarding the pilot jet, I'm pretty certain I'd cleared both well using a guitar string - but will do that again tonight to double-confirm.

One thing I should've also noted, the bike will not kick over without the choke on. This was the case from the very beginning, even in warm weather. I rode it out the second week I had it going, and anytime I attempted to turn the choke off after riding a bit and the bike would die.

Would it be wise to update the electric ignition system to something like the Power Arc from Old Britts, regardless? I've been reading plenty of good reviews, and their price for the whole kit is reasonable.

Click to expand...

When you say say choke on maybe you have it round the wrong way, cable tight is off ,a lot of people make this mistake,cheers

Ronnie said:

Thanks for the responses! I'll snap some more pics this evening and upload them.

The history of the bike is questionable, at best - I believe I am the 5th owner. The previous I owner I bought it from was the 3rd or 4th owner - he is unsure himself. He'd had it since about 2014, the owner before him had only had it a couple years. The previous owner to that had bought it off eBay from what may or may not have been the original owner in Texas. The electronic ignition was installed prior to the previous owner, and he isn't sure when.

The bike speedo shows ~6K miles on it, which is hard to believe or confirm. However, the local Norton club stopped by and took a look and based on all signs, they believe it could be original miles. It currently has the original twin Amal carbs. I believe both coils are 6 volt. I'll confirm tonight. I believe there is the amp box, and will snap pics tonight too.

Regarding the pilot jet, I'm pretty certain I'd cleared both well using a guitar string - but will do that again tonight to double-confirm.

One thing I should've also noted, the bike will not kick over without the choke on. This was the case from the very beginning, even in warm weather. I rode it out the second week I had it going, and anytime I attempted to turn the choke off after riding a bit and the bike would die.

Would it be wise to update the electric ignition system to something like the Power Arc from Old Britts, regardless? I've been reading plenty of good reviews, and their price for the whole kit is reasonable.

Click to expand...

when you say the bike wont "kick over" do you mean tickover? IE the bike wont idle?

baz said:

When you say say choke on maybe you have it round the wrong way, cable tight is off ,a lot of people make this mistake,cheers

Click to expand...

This bears a repeat, with clarification:

RELEASE the lever, releases the cables, lowers the enricher slides. "TURNS ON" the choke.

PULL on the lever, pulls the cables, lifts the enricher (choke) slides, which "TURNS OFF" the choke.

Technically, you are enriching the air/fuel mixture by "choking" air to the inlet tract.

grandpaul said:

This bears a repeat, with clarification:

RELEASE the lever, releases the cables, lowers the enricher slides. "TURNS ON" the choke.

PULL on the lever, pulls the cables, lifts the enricher (choke) slides, which "TURNS OFF" the choke.

Technically, you are enriching the air/fuel mixture by "choking" air to the inlet tract.

Click to expand...

MCS made a fortune out of this with the Saudi police force back in the 70s

Sorry, I always screw up the terminology. Don't give up on me yet, I'll get it right eventually. When I say "kick over", I'd imagine I simply mean getting the bike started up with the engine running. The bike actually starts running but doesn't necessarily hold idle (it did hold idle the first week or so after replacing fuel line and draining and replacing old oil and fuel, etc.). Currently, I'll have to give it a very slight throttle opening to keep it from dying. There's been times where no matter what I do, the bike won't even start up - even when carbs have been tickled, and doing an initial slow priming kick. Under all of the above circumstances, I've had to keep the choke lever pulled toward me to get it to kickstart.

To clarify, the bike won't run when I push the lever away from me. If I have it pulled toward me on the bike, it does run. The below picture shows the position I have to have the lever at in order to run.




Below are some photos of the bike when I first purchased it. Absent from the below images are the following changes I've since made: switched the throttle cable to a Roadster length one (used to be a high-rider cable), switched the grips and bars to the UK style lower profile, added a center stand, switched the fuel line to the Old Britts black style (https://www.oldbritts.com/image/13_065192.jpg), replaced the rear chain, and replaced the tires and tubes with 19" Avon Roadriders.







I appreciate all the advice and patience.

Ronnie said:

To clarify, the bike won't run when I push the lever away from me. If I have it pulled toward me on the bike, it does run. The below picture shows the position I have to have the lever at in order to run.

Click to expand...

The picture shows choke OFF (cable pulled tight) and it probably won't need the choke on to start it.

How clean is the inside of your tank? Are you running filters in that new fuel line?

Lark VI?

Ah yes, forgot to say the very first thing I did was clean the tank. Drained the tank and did Apple Cider Vinegar cleaning for 24 hours. It did an okay job, but still noticeable surface rust. I used Evaporust for 3 hours and was amazed at how good a job it did, in comparison. No additional fuel filters currently in the new fuel line.

Also, good eye 850cmndo. Lark VIII wagon in the background, it's a parts car for my main squeeze the Lark VIII 2-door hardtop.

Spent a LOT of time around them as a kid.

Start with some of the basics make sure both plugs are sparking ok
Take the plugs out and plug them in the ht caps and lay them on the cylinder head, then flick the ignition switch on and off they should both spark
If they don't then check the power to the amplifier (lucas ab11) then the coils
If only one plug sparks then check the ht lead and the coil connections
If they both spark try kicking the engine over with the ignition on if they both spark you are good to go
If there is no spark then you will need to check the pickup wires from the pickup to the amplifier (black with white tracer) and (black with yellow tracer) if only one plug sparks then do the above checks as the key flick test
You should find the Lucas Rita very reliable but they are getting on a bit now, and they do need a good battery
If it all checks out on the ignition then start checking the carbs/fuel pipes etc ,,,, cheers

Based on what you wrote the starting/idling issues didn't start until you cleaned the carbs, if my observation is correct then why complicate matters looking elsewhere, you'll only create new problems?

Cleaning an Amal concentric carb is a frustrating experience at best. Getting it right is like winning the lottery, getting it wrong means another hour of disassembly and dice rolling...

Replace the carbs.

If you go with Amals be aware that they come with several installed challenges, right out of the box; the good news is that they are a match for the infrastructure and the issues are well known and solvable. Maybe go with a single carb conversion?

Your Norton looks good, but you need to start a 401K plan for it...I went AWOL today and got about 50 miles on my '72, a little over an hour of being off-planet; that's when you know that all the frustration was worth it!

Thanks everyone for the feedback. After speaking with my friend who helped with the carb setup, I decided to take the Duracell Ultra battery down to the Batteries + Bulbs shop where it was initially purchased three years ago (owner had the original receipt when I bought the bike) to have them do a proper check. Sure enough, they saw the same reading of the charge dropping to 4 volts on a load. The battery has ran it's course, so I picked up an Odyssey PC625. Came home, dropped it in and fired right up - however I was getting more backfire and pops and the bike still wouldn't hold idle. I decided to take off the float bowls of the carbs to double-check the jets were clean, and upon removal this is what I saw...



One throttle needle sticking out, as it should, and one oddly stuck inside the carb body. Somehow the needle clip must've slipped off upon closure or something last time I was reassembling. Needless to say, I took apart the mixing chamber head securing screws and re-attached the clip to the needle (in middle position). I reassembled everything, cleaned the jets anyway and buttoned everything up. Gave her a few kicks, and she was running free of backfire and pops. It wasn't holding idle, so I went back to factory recommended 1.5 turns out from all the way in on the throttle stop screw. Then kicked again, and it was holding idle but pretty fast. So I adjusted each down to 2.5 turns out from all the way in, and it's now idling nicely.

One issue remains though, I'm getting hot air and a tiny bit of smoke out of the left exhaust pipe and cool air blowing out the right exhaust pipe. Does that mean I'm still only firing on the left cylinder? I checked for spark, and both sides show it just fine.

Lastly, since I've received the bike I've noticed a small amount of some sort of oil or lubricant dripping out of the seal of the left side chain case onto the left side exhaust pipe - which immediately burns said drip due to heat of the pipe and causes slight smoking too. See image of the darker area on the pipe where it burns off on...



Before I open up the chain case to exhamine the rubber gasket, is there anything I should anticipate/prepare for?