How to make motorcycle electronic ignition for £5 ($8) from a chainsaw or strimmer

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I thought I would share how I made a magneto ignition for an old 1940's WW2 motorbike from a chainsaw. It will only work on a two stroke of course and you can't advance or retard the ignition when riding. It does however work pretty well and will get you back on the road rather than just look at your bike. I know purists will moan but oh well. Keep on moaning and walking.

[@Firby1988]

This guy is a genius creating something useful from reused parts

[@Biokemist-o3k]

This guy is a genius!!

[@rocket99dan]

Very Smart. I imagine that this same technique could also be used to replace an old coil/points system on an outboard engine since the flywheel on the outboard already has the same magnet setup as a string trimmer. This would be much cheaper than replacing the original coil, points and condensor.

[@dfabeagle718]

don't know if you'll see a comment on a video this old, but this made me smile. Thanks for posting this. for what it's worth, we used business cards to gap the coil back in the day...

[@MotorClassics]

Thanks. Bit of fun it was.... moved on to bigger and heavier machines now

[@GWAYGWAY1]

Some of the magnet triggered coils have an advance according to the rpm so allow for that when strobing it. The gap is very important as too big will not trigger

[@daveg1208]

Whatever works. You are resourceful by taking parts from one thing and installing them where they weren't meant to go but works. Love it. God bless you.

[@MotorClassics]

Thanks, the difficulty with timing this by cable would be stability of the outer mounting plate. Magnetos are very sensitive with the gap changes between the core and the magnets (as in 0.0xx mm). I think it was mainly 4 stroke that had the lawn mower advance lever, but I might be wrong.

[@ogreunderbridge5204]

I´ve been thinking the thought, but I over complificated it beyond tangibility. Thanks for bringing me back to reality :) ...where did my sound go ?

[@Biokemist-o3k]

This is absolutely awesome. I wish I would have seen this before I bought my pertronix for my XS650. So incredible.

[@xvrays]

Brilliant young un you deserve 5 stars ⭐️⭐️⭐️⭐️⭐️👍

[@captlarry-3525]

it will work on a 4 stroke also ! wasted spark is common on 4 stroke and hurts nothing. static timing with only fixed advance.. standard motor scooter stuff.

[@tonystanton9223]

I like your style man, loved the vid, its so simple, and reliable, cheers for the knowledge you just shared 👍👍

[@dirkventer8112]

Everyone i have asked ses it could not be done what you did i had this idea for some time already and thank you for posting this video just to stick it too those folks that sed id will not work with out a cdi

[@transdetendal]

liked the usage! awsome to do that for keeping an old bike going! thanx for the tip.

[@airport4173]

the magnets have a NORTH and SOUTH to them and if you change rotation the coil will not give same spark. ----you have turned chainsaw flywheel round to suit bike rotation---- but many would not and get no spark or weak spark.

[@gman4dx266]

This is so very awesome! Great work! I wish I had a lathe like that, it would make my projects easier! Check out my videos where I used HEI automotive ignition on a 1980's Husqvarna 250. I had a friend helping me remove the flywheel of the original ignition and he broke the crank snout. Only problem we face now is the bike needs a battery to run and has no charging system. I have a replacement Motoplat stator and flywheel but I need to find or fab a bushing to fit the flywheel. love your idea!!!

[@RockAnAhardSpot]

That was amazing. For sure, I need to get a lath. LOL that bike is super cool. This will only work for a 1 cylinder bike, more mods would have to occur for a second cylinder. I have a lot of single cylinder thumpers around here though.

[@airport4173]

the magnets have a NORTH and SOUTH to them and if you change rotation the coil will not give same spark. --- CHAINSAW ENGINE TURNS ANTI- CLOCKWISE you have turned chainsaw flywheel round to suit bike rotation (CLOCKWISE) --- but many would not and get no spark or weak spark.

[@MotorClassics]

Air Port : I know, I had to flip the fly wheel to suit the original rotation so that it was the same as the chainsaw , not the bike. It was a 1980s Mc something..so it is correct. In the other direction it wouldn't spark at all.

[@captlarry-3525]

This is a magneto ignition.. an "electronic " ignition uses transistors and other magic devices. Magneto..mo bettah.

[@normanwells2755]

Yes I agree. But this does the job.

[@alanfoster2271]

Thanks for this. It has given me an idea as i have two or three old weed eater doing nothing,

[@turbofiat]

WOW that's freakin' awesome! I've got tons of these old Poulan 2 cycle engines I keep for parts laying about I've give you if you were not on the other side of the pond. I'm currently in the process on adapting a Hot Spark electronic conversion kit (from another vehicle) to work on my Trabant 601. I'm not all that pleased with the aftermarket system that is on the market (an it's expensive) and for some reason think I can build a better mousetrap. The plan is to reduce the circuitry in half and run a wasted spark ignition system like what's on my Citroen 2CV. I was a bit concerned using a wasted spark on a 2 stroke engine may cause an explosion in the crankcase or lead to backfiring. But from what I've read this won't happen. For starters there are rotary valves in the crankcase and when the cylinder is at bottom dead center, the rotary valve is closed. Plus you need compression for an explosion to occur in an internal combustion engine. Any thoughts on this?

[@MotorClassics]

James S : Thanks. Id have liked some extra engines to play with,pity its so far. The mag worked just fine on the bike; no problems at all. Good luck.

[@vasilispapadellis8022]

if you did this by yourself you deserve congratsulations...well done!

[@knockdolian12]

That’s clever. My mate has an XT500 . He’s putting electronic ignition on it fo £250. The only thing I can’t understand about yours is, advance. Do you time it fully advanced and hope it fires ?

[@knockdolian12]

Just read the answer 👍

[@crpth1]

Quite nice video and even better intervention to bring it back to live. Certainly it's a pity not having the "original system" but the important is done.Thumbs up. BTW don't laugh but an iridium plug would be the "cherry on top". Just a taught... ;-)

[@Taffy7974]

So glad I stumbled on this. Just what I needed to see for my bsa bantam 175cc. Question. Lights horns where from ? Sorry for the question

[@MotorClassics]

You'd need a battery and just have to charge it. Nowadays you'd use an 18650 custom pack or lipo and hide it in the battery box, that would provide enough power.

[@Taffy7974]

MotorClassics thank you. I suppose I could use a battery pack. Cheers

[@samujele]

Hi, what about implementig this technique on to 4 stroke motorcycle and with dynamo... Where should I start, because I have missing all of this things? Or should I just skip the dynamo-battery thing and make it as you are making it?

[@theq-1]

Depends if you need to use it at night / need lights. If not go the simple route and do this. It will work on a 4 stroke, the extra sparks will just be wasted.

[@philliptoone]

I misread this and thought that you were going to talk about CDI ignition. Great video but I'm going to keep looking for CDI information. Thanks.

[@transdetendal]

what your needing?

[@angelsone-five7912]

That`s really quite good but as I see it the timing is now fixed and the same throughout the rev range, is that right?

[@MotorClassics]

Yes it is, but for smaller engines (up to about 350 cc ) it doesn't matter too much. This one was a 200cc .

[@datadavis]

does it come with programmable timing curves? 😃 great work mate!

[@smacmax]

How did you remove the armature from the flywheel

[@patricknoone3431]

excellent video, thanks.

[@gordontarpley]

GREAT idea

[@blohmymind]

Nice work.

[@Rayxl1]

I'm doing that with my honda nc50 express with bits I got out of an old strimmer.

[@db5153]

Rayxl1 let me know how that turns out! I just replaced my return spring but now I've lost the shims so now my axle won't spin but she starts

[@Rayxl1]

It works very well and its so much more reliable. One advantage is you can adjust the timing easier. I've got it about 20 degrees in advance of what honda recommend and that gives the most power. Doing that with the points gave a very small gap which was difficult to maintain.

[@yannkitson116]

Excellent work!

[@59jaguar]

Good job man! Now to get that thing so it doesn't sound like a weed trimmer;)

[@dirkventer8112]

Can this be done on any two stroke engine regardless of the stroke length or do you need to make a bigger or smaller diameter fly wheel to compensate for stroke length im thinking of doing something similar with a old kx125 engine where the parts have been discontinued or exstreamly difficult to find

[@MotorClassics]

Yes will work with any, wont be that great with high revs but will chug along on an old bike no probs.

[@soupertrooper3864]

@@MotorClassics You know there's no reason this won't work on a 4 stroke... Your video has inspired me to fix my old KL250 which ignition parts are hard to find for and too expensive for my purpose which is riding it off road... and also bigger chainsaw engines are usually rev limited to about 12,500 rpm.... And have a timing curve built in...

[@mashkoor78]

self start in yamaha rx 100 possible?

[@fcukmegently]

Well done that man!

[@inthenameofjustice8811]

Superb stuff. Thank you

[@fastback777ray]

nice vid. can you help me with some advice for a 2 stoke 2 cylinder bike? a friend of mine has a Yamaha RD350 which he'd like to do away with the contact point?

[@MotorClassics]

Hi youd probably need two mag flywheels and trim them down. failing that youd need a proper electronic ignition kit.

[@fastback777ray]

thanks...will give it a try

[@thepyrodude]

2 cylinders can be fired by one cdi just need to time the 2 pick ups to fire at the right time but there is ignition conversions out there for the RD yamahas

[@upsidedown1986]

Excellent, thanks 👍👌

[@LukaBean10-4]

Has anyone came up with a solution to not having a charging syestem yet?

[@AIRMANBEAR]

BRILLIANT ED IN N.Y.

[@michaelflanagan6936]

This is magic. But.......................... I don't understand why the flywheel was installed back to front to make the engine run in the right direction. Can anyone explain this before I make the same mistake ?

[@robotgeek6262]

I think from memory that the magnets in the flywheel where different somehow (one was stronger than the other) and this then altered the exact timing in that the spark occurred too early and the piston was still on the compression stroke when the spark fired forcing it back down the wrong way.

[@madmarkstoys]

nice job !!!

[@bustergonad6660]

Good man!!

[@jenntek.101]

fly wheel puller = rope on the piston trick....

[@MotorClassics]

Jenn Tek Dont know that one?

[@jenntek.101]

Remove spark plug - insert rope in jug. crank slow so rope holds piston down (Never makes it to TDC) and undo your pulley. :)

[@NorCalJoe1966]

Awesome !!!

[@djdarkrcom]

There is no advance unit??

[@MotorClassics]

You don't need one on a crude old two stroke. Its not the most efficient way but neither was the engine design to start with so they only had a air slide / choke lever; much like a weed wacker.

[@Ex-fk4nr]

Nice

[@FlyingPlatypusGamess]

dont even need a cdi nice!

[@colea6341]

brilliant... pureists be dammed lol

[@jeffmullinix7916]

The only thing is that this is only good for about 7500 RPMs then the spark starts to fade away .

[@MotorClassics]

7500 rpm for a vintage 2-stroke is more than plenty

[@richardjeffery517]

Looks like a m20

[@MissShaftable]

MacGyver it brotha, I'm the same way with stuff, if there's a will there's a way.

[@mcozpda3392]

ahahahhaahaaa .. i like ... i think i put one in my harley .... easy and better ...