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Clueless on how to start my KM20 or stop it for that matter

OK you folks are in for a good laugh. I am getting close to putting petrol in the refurbished tank. I got a nice 6V AGM 8.2AH. I energized the dynamo, connected the battery and checked the switch for lights. Yes all lights work. So far so good.

Now I want to see if I have spark. I put the switch in T and kicked her over. Yes I have spark. Great. So I turn the switch to off and kick her again. Still got spark. OK, the switch seems to be for the lighting system and the amp meter seems to run through it also.

OK I disconnect the battery and kick her again. Low and behold I still have spark. I get the magneto makes the spark. If I get it running how do I shut it down! I guess I can cover the carb with my hand.

Please set me on the right track PLEASE

Thanks
Charlie

email (option): cbhaws@verizon.net

Re: Clueless on how to start my KM20 or stop it for that matter

Yes you have worked it out for yourself. The battery and switch are for lights and horn only. The mag is for sparking the plug. You should have a valve lift lever on the clutch end of the bar for easier starting and for stopping the engine. Ron

email (option): ronpier@talk21.com

Re: Clueless on how to start my KM20 or stop it for that matter

OK I found a better wiring diagram. This one shows a thing you guys call a dipper switch. Yes in one position no spark in the other I get a spark. Problem solved.
What really cracks me up up is I read several selections explaining start-up. Great length is given to cranking slowly to find compression stroke, release compression and go just past TDC. Then release compression lever. Advance the throttle just a little after tricking the carb. Remembering to retard the advance a little. Then kick the crap out of it.
No where, but no where does it say to make sure you have your dipper on.

Man things I have to remember or get translated, dipper, fag paper, petrol.

Thanks

email (option): cbhaws@verizon.net

Re: Clueless on how to start my KM20 or stop it for that matter

Absolutely no electrical contact, switch or connection on a standard M20 should have any effect on a magneto spark. The only reason for this would be if a modified points cover has been fitted to allow a switch to short-out the points. The only cable anywhere near your magneto should be the HT cable to the sparking plug.

A dip switch swaps the headlamp from high to low (dipped) beam. What do you call them ?

Re: Clueless on how to start my KM20 or stop it for that matter

Charlie. I guess this would be something like the controls for a KM20. It's the BSA pre-war set up that carried over to the first WD bikes into 1940.
The dipper as you and others might call it (I call it the dip-switch) is mounted on the clutch lever (or a separate handlebar mounted switch) and as Rik said is for dipping the headlamp....as per pretty much all vehicles require!

On top of the clutch lever is the valve lift lever, which as you've observed is to get the engine over compression for easier starting...And to STOP the engine. The long lever further down the bar is for the ignition advance/retard.

God knows how your dip switch has anything to do with the ignition? Any chance of pictures of your bike and set up. Send them to me an I'll post them if you want.....We're hear to help. Ron

M20-310

email (option): ronpier@talk21.com

Re: Clueless on how to start my KM20 or stop it for that matter

The magdyno consists of two completely separate units...The magneto is a self contained, self generating ignition unit which does not require any connection to, or electrical input from, the rest of the electrical system...

The dynamo, which is strapped to the top of the magneto, generates the electrical power for battery charging, lighting etc. and has no function as part of the ignition system....

Therefore, on a bike with a standard wiring circuit all wiring/switches, the regulator and the battery have no part in providing a spark for ignition...

The only exception to this is if the contact breaker cover has been modified from standard to include a connection that would earth the contact breakers to the chassis of the bike or some other earthing point...In that case a single wire will run from a connection on the contact breaker cover, to a switch and then to earth...That set up would 'switch' the spark on and off as the switch was operated...This isn't a particularly common modification but some people do fit them so you have to determine whether that has been done to your bike....Ian

email (option): ian@wright52.plus.com

Re: Clueless on how to start my KM20 or stop it for that matter

On reading this, I thought I would pop out the back and make a short video on how I start my WM20. Please be kind ! I don't normally do this type of thing. I am passed 50 now, maybe should get the grandaughter to do it !! Hope its correct and that it helps..

https://youtu.be/w9cLTeBHYtI

email (option): richardpurkiss@hotmail.com

Re: Clueless on how to start my KM20 or stop it for that matter

Thank your Richard,
I think I have got it now. Hopefully the magneto provides enough spark. I can see the spark jump the plug gap. Tomorrow with so oil in the engine I am going to attempt to start her up. It has been sitting for at least 5 years. Maybe longer.
Nice YouTube video
Thanks again,
Charlie

email (option): cbhaws@verizon.net

Re: Clueless on how to start my KM20 or stop it for that matter

Hello Richard,

Great video! I wish that this video was here years ago when I was trying to start my bike for the first time. Old seasoned pros take such basic information for granted. This will be very helpful to the newcomers of WD motorcycle ownership. Also, it was nice meeting you and Alwyn in Bayeux last June 6th.

Cheers,
James

email (option): jamescusteau@yahoo.com

Re: Clueless on how to start my KM20 or stop it for that matter

Thanks Jim. Nice to have met you too. Those few days were a blur !

email (option): richardpurkiss@hotmail.com

Re: Clueless on how to start my KM20 or stop it for that matter

Great video Rich, I thought the editing was seamless, Spielberg had better watch out 😁

Re: Clueless on how to start my KM20 or stop it for that matter

Ha!.. it took me all of 5 minutes...and it shows !

email (option): richardpurkiss@hotmail.com

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