Boyer Mk4, battery-less

[Easy-X]

Was having a look at an old Triumph and it's got one of these electronic ignition kits fitted. The bike really doesn't like starting and I'm wondering whether the "will run battery-less" in the Boyer fitting instructions is more an aspiration than a reality
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[MarJay]

You will need to replace the battery with a suitable source of resistance, but otherwise I'd imagine it'll work.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Easy-X]

[stinkwheel]

Depends on what the electronic ignition is. Some self-excite, some still take the power from the charging system.

If it's the former, it wouldn't make any difference if you had a battery or not.

EDIT: Ahh, the clue is in the title. It's the latter. Boyer Mk4s are notoriously fussy about having a healthy voltage supply, the advance curve goes all screwey if they have low voltage.

The Mk4 is being phased out, apparently the Mk5 is much less error prone.

I would not try to use one with a batteryless charging system.

The boyer power box WILL work without a battery but you need to get the engine spinning fast enough to generate the 12v that the ignition unit needs. I bet you're only getting a spark every third kick when the capacitor in the power box is charged up, and that is probably timed wrong.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MarJay]

All the bikes I've ever seen with batteryless ignition required some sort of resistor or something to add enough load to the charging system. We'd probably need a bit more info on the layout of the charging system.

However, old Triumph, kickstarter, not loads of electrical load from 4 indicators, a stop and tail and a headlight, there's no reason why it couldn't be made to run without a battery, especially if the electronic ignition manufacturer says so.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[wr6133]

Both my bullets use boyer igntions and power boxes.

Run batteryless my arse. Tried on the 350. Yes it works if you are on a legs day and don't mind kicking the thing 999999999999999999999999999999999999999999999 times to get it going.

[Robby]

It sounds it will run without a battery, it just won't start without one.

Probably a good candidate for an AGM battery like a motobatt, they seem to be far happier than most when left alone for ages. I have one in the garage that occasionally gets used to run odd 12v things. Recently put in a charger after sitting doing nothing for a year, all the green lights immediately.

[Easy-X]

[stinkwheel]

Dinkiest lead acid battery I could find was a lucas YTR4ABS.

https://www.tayna.co.uk/motorcycle-batteries/lucas/lytr4abs/
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Easy-X]

It's been a while but I had a good session wiring up the bike today. To keep things simple - as the previous wiring attempt was a bust - it now has a T140 factory loom. Hardly anything wired in but all the right colours

Two circuits effectively: power/charging and ignition. As a test I just kicked over the bike (without the plugs) to monitor how many volts were coming out of the "power box" and I couldn't get it much above 6 volts (with the Mk4 electronic ignition disconnected.) Maybe half a dozen swift kicks then turn on the ignition, kick again might get it started but seems like a lot of effort.

Inserting a battery into the mix? Totally different story! Angry blue pixies released on every kick It was getting late so didn't go as far as putting the tank back and trying to start it but I'm pretty confident it'll be fine barring timing issues.

Waiting on a battery that'll fit and a suitable holder to be fabricated and hopefully it'll just be fiddly bits like brake lights to wire up.
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter