Possible Magic E-Button Mod?

[bufftester]

So watching the tear down on SerpentZA's SR in China (thread is here) and one of the pics started an itch in the back of my brain. According to the parts microfiche, they show the H-series KDX/220 cases as looking like this:

The interesting part is the area circled in red...but on my 2001 KDX220 case it looks like this:

with none of the structure in the diagram visible. In SepentZAs thread he shows the inside of the case on the right hand side and it looks like this:

again, the interesting bit is circled in red, those gears aren't present in the US model bikes:

But now the itch is going about whether or not the SR arrangement could be retrofitted to the newer KDX? I have an old motor I don't mind cutting on if this could work, I am thinking the hard part is going to be finding a starter motor/gear train to graft on. Any of our SR brethren out there have more pics of this area that they could share? Thoughts? Opinions? Should I just go back to quietly coloring in the corner?

[Gotanubike]

That's neat, I saw that too and my first thought was that it was a pump mechanism for oil injection

[bufftester]

Now that you say that it makes more sense...keep forgetting that the SR is oil injected. Maybe my idea is technically flawed from the start. I know that on most E-start 2Ts they turn the flywheel through a worm gear, just seemed like this would be a more elegant arrangement. May still try to pursue this line of thinking though. My dad refuses to give up his 94 E-series bike, but at 74 with his right leg rebuilt from Viet Nam the electric start would be an awesome improvement that would make his riding time more enjoyable. My other thought was to remove the kick starter and come up with a gear arrangement to drive the kickstart shaft. Time to get out the Autocad...

[pumpguy]

Great idea. I hope you can do it. I've even thought about substituting a Rokon style pull starter to replace the kicker.

[chkdx]

I've wondered about modifying the magneto cover to use the spring loaded restart setup that comes on some lawnmowers; when the engine starts, it winds up a spring, then the next time you shut the engine down, then (on the mower) you push a button on the mower recoil starter that causes the spring to engage the crankshaft and spin it. Only works on quick hot restarts, doesn't crank long enough for a cold start.

So I wonder if the spring loaded restart mechanism could be built into a modified magneto cover on the KDX, and activated by a cable to a small lever on the handlebar. Great for quick restarts on the trail, probably work after a tip over, and no battery needed!

[Julien D]

I would say that is almost certainly the setup for an SR oil pump. Perhaps one of our SR owners can verify? Could totally be used for e-start if you can spin that little gear fast enough without destroying it. It would have to be able to turn that kickstart gear as fast and with as much torque as you use with your foot. Who's our resident engineer??

Very cool post! Got me thinking about something that I never would have thought of, lol!

[chkdx]

Well, just spinning that little gear with a starter motor won't work. That little gear spins all the time the engine is running. The kickstarter only engages its gear when being kicked, and has an overrunning clutch built into it. It wouldn't work to install a small starter motor with a built-in overrunning clutch on that little gear; the overrunning clutch would be overrun all the time and quickly overheat.

FWIW, I am an engineer that co-owns a company that manufactures high performance gear reduced starters for classic muscle cars. Here's a link to one of our starters:
http://www.robbmcperformance.com/produc ... arter.html

Now, a starter motor that engaged that little gear only during starting, and retracted the little gear out of engagement once the engine started would probably work very well! Hmmmmmm...........

[bufftester]

I'm an electrical engineer, not a mechanical, which is why I was deferring questions to the rest of you. My other thought was a starter that engages the kickstart shaft through the backside of the case (picture 2 above, just below the blue taped crankcase vent) Since that shaft only turns when starting it would be a good candidate, wouldn't it? You could drill the case in the center of the bearing surface and engage the starter motor right to the end of the shaft. I have a bunch of starters from my GSXRs that are 4 cylinder engines with each cylinder running about 180 psi compression so they should have plenty of torque to drive a single cylinder 2T.

[chkdx]

I don't see why that wouldn't work bufftester. I'm sure some machining would be involved to get everything working.

[newbbewb]

My dad refuses to give up his 94 E-series bike....

me either. I will be buried with it, with or without E start.

[Julien D]

Well, just spinning that little gear with a starter motor won't work. That little gear spins all the time the engine is running. The kickstarter only engages its gear when being kicked, and has an overrunning clutch built into it. It wouldn't work to install a small starter motor with a built-in overrunning clutch on that little gear; the overrunning clutch would be overrun all the time and quickly overheat.

FWIW, I am an engineer that co-owns a company that manufactures high performance gear reduced starters for classic muscle cars. Here's a link to one of our starters:
http://www.robbmcperformance.com/produc ... arter.html

Now, a starter motor that engaged that little gear only during starting, and retracted the little gear out of engagement once the engine started would probably work very well! Hmmmmmm...........

Yeah, like a starter does with a solenoid to "push" the starter gear into engagement and retract after.

[scriberman]

Lots of bikes have a "overrunning clutch" ( sprag) that runs all the time. The big Jap bikes use three rollers type. http://en.wikipedia.org/wiki/Sprag_clutch
You would also need a lot more reduction. Still worth a go.

[chkdx]

Do you mean they have an overrunning clutch on the starter that overruns all the time when the engine's running? If so, that's a surprise. Not saying they don't, just surprised. Given the amount of gear reduction necessary for the starter motor to crank the engine, that would mean that the sprag would be oversped to the tune of 50,000 rpm or more at an engine speed of 10,000 rpm. Most sprags can take that for a short time, but not very long. Maybe the bike starter spags can, though.

If you mean they have an overrunning main clutch (also known as a slipper clutch), those don't overrun all the time, only on deceleration to prevent rear wheel lockup, and the overrun rpm is much less, typically 1/3 or so of engine rpm (depending on the primary drive ratio), so they don't heat up near as much.

[sarrant]

Usually the sprag clutch on a motorcycle are after the gear reduction, or to be more exact, they are themselves the gear reduction, as a clutched large gear assembly running somewhere between the tiny starter pinion gear and the primary

[chkdx]

Ah, ok, that makes sense.

[koshari]

Its definately for the oil pump. The pump then would then inject the oil through the robber bit that connects the carby to the reed cover.

As far as electric start goes i have a 125 kickstarted on mine and its fine,

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