TOPIC:

On a smaller bike that is kickstart only, could I create a temporary electric starter using a drill?

Formula 1 cars use something like that, but it is pneumatic and pretty powerful. I'm picturing something smaller, because I'd like to be able to start the bike while it's on the stand and kicking is not possible.

What I'm considering is taking a spare kickstarter, removing the end that goes over the splined shaft on the engine, and welding that end to a flat piece that is in turn welded to a short piece of heavy steel rod that can go into the chuck on the drill. If the drill is set to turn counter-clockwise it should emulate the kicking motion but in a continuous fashion. It would likely need to turn slowly to align with human kicking speed. If the cordless drill is not strong enough, which is entirely possible, I have 3/8" and 1/2" corded drills that should get the job done.

Or... Because the kickstarter is designed to go through 90 or 100 degrees of motion - kick, reset, kick, reset, etc. - is the pawl that engages the shaft going to fail because it wasn't meant to go all the way around? I might need to disassemble it to know for sure [to see if there is any interference]. I'm thinking specifically of part #5 in this diagram:

 


Has anyone here ever tried this?

Rather than use the kicker splines why not use the nut on the end of the crank in the ignition housing. 
Just need a socket to suit then and no worries about the kick shaft suitability.
As its on the stand you want to start it having the ignition cover off is no issue as your obviously not gonna ride off anyway. 

That's a much better idea! Why didn't I think of that?

It uses existing features and parts, and it means no welding (which is good, because I'm not great at it yet). Cheers, mate!

Not sure how successful you will be with this, if you look at the starter clutch and starter pinion it's about an 8:1 ration to multiply the torque (paddock starters have a set of reduction gears in the nose) also how is it going to disengage when it starts paddock starters have a specially designed fitting to "cam out" the starter when the engine fires?
Love the pioneering spirit though 

Crank end nut is the only way to go if your not using a kick lever.
You would probably have to fabricate a steel nut, I don't think the aftermarket ever made a starter nut for a
engine that small (Z1 yes) not sure if the crank end taper is the same.
You would have to have a drill with a lot of torque, even with a stock 400cc engine.


 

Wookie58 wrote:

Not sure how successful you will be with this, if you look at the starter clutch and starter pinion it's about an 8:1 ration to multiply the torque (paddock starters have a set of reduction gears in the nose) also how is it going to disengage when it starts paddock starters have a specially designed fitting to "cam out" the starter when the engine fires?
Love the pioneering spirit though 

 

Much appreciated However, this is a kickstart only bike, so there is no starter clutch.

I've been pondering the question of disengagement. If I use a socket on an extension, and have the extension in the drill chuck, I might be able to separate the extension from the socket and then retrieve the socket from the engine after shutting it off.

OTOH if the drill is spinning under its own power while the engine is idling, perhaps that will allow the socket to disengage since there will be less tension (rotational tension?) on it.

Injected wrote:

Crank end nut is the only way to go if your not using a kick lever.
You would probably have to fabricate a steel nut, I don't think the aftermarket ever made a starter nut for a
engine that small (Z1 yes) not sure if the crank end taper is the same.
You would have to have a drill with a lot of torque, even with a stock 400cc engine.
 

Also appreciated

And sorry, I should have been more clear: this is for a single-cylinder Yamaha 250, rather than a KZ. I was going to post this in the Engine category but then decided it should go in Bike Related to separate it from the Kaw content.

No worries, the starter clutch reference was to highlight the gearing required to spin the engine with an electric motor that size. As you can see the below "off the shelf" item also uses reduction gears 

 

You'll have no issue removing the socket. Once it fires you'll have more trouble keeping it on there than taking it off.
Wookie is right you'll need a big drill to turn it over. Especially if it's a large capacity single. I use a large kango type drill in rotation mode to start my bench builds and even that was touch n go powerful enough on a 1100 4 cylinder. 
 

The starter motor I use on my 650 drag bike is off a Chrysler 440 V8 engine, 24 volts running off two 1000 CCA truck batteries.

Warren3200gt wrote:

You'll have no issue removing the socket. Once it fires you'll have more trouble keeping it on there than taking it off.
Wookie is right you'll need a big drill to turn it over. Especially if it's a large capacity single. I use a large kango type drill in rotation mode to start my bench builds and even that was touch n go powerful enough on a 1100 4 cylinder.
 

It's only a 250 with a CR of 9.2:1 IIRC. To me a large single is 500+cc - my brother had an XT600 and kicking that was an adventure.

The bigger corded drill is a 1/2" Craftsman from 40 years ago. It has a second handle that screws into the top, opposite the molded handle, so it doesn't twist out of your hands. It's a beast.

What have you got lose (except a garage window when the socket flys off  ) just watch you don't break your wrist