Mk3 Estart

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worntorn

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My MK3 Estart has been non functioning for several years now. It sort of worked when I bought the bike 14 years ago, but the sprag slipped a lot. I fitted a new $150 sprag from Norvil and that self destructed after a couple of dozen starts.
So it's been kickstart only since then, but it is an easy starter( Early Boyer)
As others have noted, the early Boyer and the Estart are a bad mix.
Unless the battery is at tip top voltage, the starter drags the Voltage down too low for the Boyer to function properly. Kickbacks occur and the sprag can break.
Or as mine generally did on cold start, it whirled over with gusto but only fired when the starter button was released.

One cure for this would be to fit a new ignition which will work at a lower voltage, or to fit the original points back in the bike.
Other than the Estart problem , I do like the old Boyer, can't fault it and it is proven.

My intention was to redo the starter drive with the new high grade CNW Mk3 drive parts when those came available and that might still happen. At the moment tho, the CNW parts are not available and it seemed like time to get this starter working again.

I have two modern bikes which have EI that is supposed to be able to function
at lower voltage. The Triumph Daytona can be a bit of a bear to cold start after sitting for awhile, even with a fully topped battery. I always assumed that this was just a case of needing to roll over a fair bit to get fuel into the dry cylinders. One day, quite by accident, I cold started the bike with the big battery charger still attached to the battery. The bike hadn't been started in months but it started instantly, as though I had just shut off the warm engine and then touched the button.
That had me thinking about the Commando Estart.

So this was the plan- fit a tiny second 12 volt battery on the bike somewhere and switch the ignition circuit through a separate direct fed, on off on, double pole double throw toggle switch in a hidden location.
In forward position the ignition circuit is fed by the isolated small battery and gets full voltage , the starter motor rolling over has no effect on it. In rear position the main battery supplies power to the ignition plus the switch is jumpered so that the small battery is now in parallel with the main battery . This means that the small battery gets charged along with the big battery in normal running.

I can report that this works beautifully, the bike cold starts instantly just like the Daytona did with big battery charger connected.
The second battery is quite tiny in size, just 1.3 ah and about an inch and a half thick by two inches high and three and three quarters long. I made a mount that fits to the left side shock bolt, the battery sits right there under the seat and between the rear fender & the seat frame loop. Cost for the battery was $21 at an Electronics shop.

I also fitted a $17 Chinese sprag from Alibaba. Too soon to say if it is good or bad, but it has already outlived the expensive Norvil sprag.

Glen
 
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That sounds like an interesting solution.
Are you certain that the tiny 12 volt battery won't be damaged from the charging current that the system delivers to it.
Does your MK3 use heavier ground and starter wires?
 
I don't think the charging will bother the 1.3 ah battery but time will tell.
Yes, the original starter wires have been replaced with heavier wires. This was done by the previous owner.

Glen
 
I was going to start a thread on my MK3 starting experience , but yours is a real close match so heres goes my mystery. I have two MK3's one I have had for twenty years plus, its got the updated works, 4 brush, 4 field coil starter , big cables, preMK3 battery box , huge battery,RM24 alternator , Lucas Rita ignition, (no kickstarter , don't need it) and it never fails me. My latest MK3 I have been working on, is all stock,( I wanted to see how bad it would be if it was all oem) , everything except the old style Boyer ignition! I cleaned up the stock cable ends, got a new battery that fits the MK3 tray, got a new replacement solenoid from Napa, an exact fit, cleaned up the stock starter , cleaned/lubed up the stock starter button. The fully stock setup almost starts better than the modified one! It shouldn't work at all. So whats up with that?o_O My guess its the new $35 battery.
Mk3 Estart
 
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When I brought my new 74 850 I could have payed some extra money and brought the M111 , although it was classed as a electic start the sales man told me in realatity it was a kick start helper, kick and use the starter at the same time and they fire up straight away, when new they were very lazy to start with just the ES, but now there are better upgrades for them better batteries with more amps even better starters on the market, I still love kicking my Norton alive and I always get people watching when out and about.

Ashley
 
Without having the early Boyer firing against the sprag, or a mechanical advance stuck full advanced, the sprag has a better life expectancy!

Your solution, while elegant, seems to ignore the advantage of later electronic ignitions like the Pazon which have a better advance curve and will fire when the the voltage is lowered by the starter draw. My Boyer went in the trash and good riddance. A locked sprag leaves you with no option but walking.
 
Jim, I mentioned that my 2 modern motorcycle electronic ignitions,that will work at lower voltage like Pazon ,work a lot better at full voltage.
With the isolated second battery you always have full ignition voltage for starting.
I have a third bike with modern EI. It uses a recently manufactured $1200 Pazon Smartfire system. Although it will work at 11 volts , it doesn't work all that well at that voltage.
The old Boyer with full voltage seems to make a much hotter spark than the modern EI with less than full voltage. And the cost for the hot spark was $21.

No need to throw the old Boyer out if the voltage problem is solved.


Glen
 
I was going to start a thread on my MK3 starting experience , but yours is a real close match so heres goes my mystery. I have two MK3's one I have had for twenty years plus, its got the updated works, 4 brush, 4 field coil starter , big cables, preMK3 battery box , huge battery,RM24 alternator , Lucas Rita ignition, (no kickstarter , don't need it) and it never fails me. My latest MK3 I have been working on, is all stock,( I wanted to see how bad it would be if it was all oem) , everything except the old style Boyer ignition! I cleaned up the stock cable ends, got a new battery that fits the MK3 tray, got a new replacement solenoid from Napa, an exact fit, cleaned up the stock starter , cleaned/lubed up the stock starter button. The fully stock setup almost starts better than the modified one! It shouldn't work at all. So whats up with that?o_O My guess its the new $35 battery.
Mk3 Estart

I think you've got it right. With the new battery, the voltage is likely high enough to fire the ignition properly plus give the engine a quick spin.
 
Jim, I mentioned that my 2 modern motorcycle electronic ignitions,that will work at lower voltage like Pazon ,work a lot better at full voltage.
With the isolated second battery you always have full ignition voltage for starting.
I have a third bike with modern EI. It uses a recently manufactured $1200 Pazon Smartfire system. Although it will work at 11 volts , it doesn't work all that well at that voltage.
The old Boyer with full voltage seems to make a much hotter spark than the modern EI with less than full voltage. And the cost for the hot spark was $21.

No need to throw the old Boyer out if the voltage problem is solved.


Glen
Glen,

I like the solution but I suspect that it's not that the other ignition systems don't function quite as well at lower voltages it's just there's lower primary voltage at the coil. The EI simply functions as an on/off switch. As long as it's at the right time as opposed to the Boyer, which may be way out of time at low voltage, it is as good as it can be.

I find the Altair, with a smarter advance curve, takes a little flat spot out the Boyer cannot with its straight line advance.

I'd like to suggest a further modification which will totally automate the system. I used to use isolation diodes to charge the house batteries in boats. The problem is the slight voltage loss through the diodes. The better way now is voltage sensitive relays which isolate the house battery until the alternator comes on line then they tie to charge. You could put such a relay between your ignition battery and main and it would automagically charge without flipping a switch yet be isolated to supply 12 volts for starting.
 
That sounds like a good method for switching. I might try that with the Daytona, it clearly would like more ignition voltage for cold starting.
Same as the Norton, it has room under the seat for one of these tiny batteries.

Glen
 
With an upgraded starter, and decent battery Yuasa or better, leads etc the existing system will work very well without having a second battery. Some when fitting EI and using the 6V coils forget to take the ballast resistor out of circuit, which negates any advantage of the EI. Also, most upgraded / replacement starters draw less current in use and are not so savage to the battery as the original.

I flashed the MK3 up this morning at an indcated 1 Deg Cel, primed the premiers, choke on, ign on and hit the button - started first hit, choke off after 15 secs and she ticked over lovely.

Battery switching and charging technology is great these days, and nigh on prevents over charging and excessive draining, always worth considering when using two or more batteries in any application or touring and using the battery to run phones, Cardo scala and tablets etc when the bike is not running.
 
I think you've got it right. With the new battery, the voltage is likely high enough to fire the ignition properly plus give the engine a quick spin.
So, To logically draw an conclusion;
if my completely stock setup worked great with the new modern battery the poor performing batteries that were installed in 1975 were the only problem leading to the starter systems bad reputation?
 
More than likely, some still run the old setup with just improved leads and new 'correct' battery, not the lesser battery that can be specified for the MK3, remember that the parts book ref I think still calls for the 12Ahr battery, not the 14Ahr, not sure what bikes left the factory with in the 70's.
 
More than likely, some still run the old setup with just improved leads and new 'correct' battery, not the lesser battery that can be specified for the MK3, remember that the parts book ref I think still calls for the 12Ahr battery, not the 14Ahr, not sure what bikes left the factory with in the 70's.
I used the stock cables too, the 14 amphr AGM bat might be the ticket then .
 
So, To logically draw an conclusion;
if my completely stock setup worked great with the new modern battery the poor performing batteries that were installed in 1975 were the only problem leading to the starter systems bad reputation?

That and possibly a subprime charging system in some cases. Some time ago Jiim Comstock noted that his nearly stock MK3 with all original starter system but upgraded charging system started easily.

There are a number of ways to get more volts, the second isolated battery is just one that I've wanted to try.
All of the other combos give somewhat lower than full ignition voltage.
I like the idea of $20 for 12.5 or more volts to the ignition while starting.

And having another 1.3 ah of battery to run the ignition dead loss in the event of a charging system failure is a bonus. My only major old bike problem while touring has been charging system failure, including failure of two completely new systems. Dead loss running and 110 Volt charging at night got me home.

Glen
 
Rather than using a second battery, why not fit multiple 2MC capacitors or a capacitor module for the isolated ignition circuit? It has been stated at other sites that 30 000 to 45 000 uF is sufficient to replace the main battery on a bike with EI using the kickstarter. Norton fitted a single 2MC for emergency starting using the K/S. The capacitance of the 2MC is quoted at 4500 uF/30V and is capable of delivering 4 Amperes for 1 second. One 6V type 17M6 coil pulls 4 Amps, so it would be reasonable to provide at least a 27 0000 uF capacitor for a 3 sec starting sequence when using the E/S. Yes, there is an ageing problem with the 2MC capacitors - as is the case with batteries - this may or may not be a problem with newer replacements or a dedicated capacitor module.
 
If I had a MK111 I think I would be tempted to go back to points ignition, as when the engine is being cranked the ballast resistor is bypassed and full battery voltage applied to the 6V coils.
Probably about 9V when cranking?
 
Rather than using a second battery, why not fit multiple 2MC capacitors or a capacitor module for the isolated ignition circuit? It has been stated at other sites that 30 000 to 45 000 uF is sufficient to replace the main battery on a bike with EI using the kickstarter. Norton fitted a single 2MC for emergency starting using the K/S. The capacitance of the 2MC is quoted at 4500 uF/30V and is capable of delivering 4 Amperes for 1 second. One 6V type 17M6 coil pulls 4 Amps, so it would be reasonable to provide at least a 27 0000 uF capacitor for a 3 sec starting sequence when using the E/S. Yes, there is an ageing problem with the 2MC capacitors - as is the case with batteries - this may or may not be a problem with newer replacements or a dedicated capacitor module.


That could work, maybe someone will do the test. I'm not sure what advantage it would have over the tiny isolated battery, especially if multiple capacitors are involved.

Re Brightspark voltage monitors - I'm a fan of these and have used them for a few years now. The Commando has one in place . It shows what is happening with ignition supply voltage because it reads from that circuit.
With the toggle switch to the rear, main battery +second battery connected, the monitor flashes low ignition voltage while cranking. This would be even lower, though slightly, without the second battery. The longer you crank the lower it goes.
With the toggle in forward position, the monitor shows a steady amber light(+12.45 volts) while cranking. Because the battery is isolated and only has ignition draw, cranking time has no effect on ignition voltage, should the owner forget to turn fuel on etc .
Naturally, the bike starts much quicker, almost instantly, with the high voltage ignition supply.

Glen
 
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