How to set the Coil to Flywheel Gap - Pocket Bike Forum - Mini Bikes
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post #1 of 2 (permalink) Old 03-28-2011 Thread Starter
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How to set the Coil to Flywheel Gap

This How-To will attempt to give you a little bit of information about the coil / flywheel and why it's important to set the gap.

The engine could not run without a spark, On the C1 / B1-rep (and most 2-stroke pocket bikes) the engine relies on the spark plug creating a spark at the right moment to ignite the gas mixture and power the piston back down to BDC.

The Coil and flywheel create and send this power to the spark plug at just the right time, we need lots of voltage because we need a spark that can bridge the gap it will run into when it goes through the spark plug.

The more voltage we can create and send to the spark plug the better we can ignite the gas mixture and by burning more fuel we make more power.

The gap between your coil and flywheel play a huge role in making this voltage.

In picture 1 we can see the Coil, on top, and the Flywheel on the bottom.

You should see that there are two holes where the mounting bolts go to hold the coil in place, the holes are tall enough to allow you to loosen the two mounting screws and move the coil up and down.

So, Start by removing the pull start / cover, now you should see something like in the pictures, loosen the two mounting bolts for the coil.

Now grab a business card (not a credit card!) one of my cards is a little less than 0.5mm, bend and place the business card between the Coil and Flywheel as shown in picture 2 and 3.

With the business card in place rotate the engine 360 degrees keeping the business card between the Coil and Flywheel , if you notice any "High Spots" on the Flywheel try to end the rotation with that high spot pushing the Coil as high as it will need to so it can rotate without touching the Coil.

Slightly tighten the two mounting bolts, you want to try to keep the coil from moving, but still need to remove the business card, so start to work the card out while tightening the mounting bolts more and more until both bolts are tight and the business card is all the way out.

Slowly rotate the engine (BY HAND!) making sure the Flywheel and Coil don't touch.

Double check the two mounting bolts, and replace the Pull Start / Cover.

You're done! Grab a cool drink and continue on to your next problem.

Attached Images
File Type: jpg fwcoilgap.jpg (259.7 KB, 141 views)
File Type: jpg fwcoilgap2.jpg (315.5 KB, 121 views)
File Type: jpg fwcoilgap3.jpg (176.7 KB, 116 views)

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post #2 of 2 (permalink) Old 03-28-2011
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Re: How to set the Coil to Flywheel Gap

very nice. im digging the 3D graphics. i saw them in another one of your threads but not all together like that. great write up!!
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