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Discussion Starter · #1 ·
Ok so I've been messing around with these bikes for a while now and I've got a question that I can't find an answer to.

With coil gap is there any such thing as too close as long as the coil isn't rubbing on the flywheel ? I know the standard is a piece of thin business card, I personally use a piece of thick sandpaper but was wondering if that might not be a good idea as its about half as thick. Don't get me wrong it works well I get decent spark and no rubbing but I thought it might be an idea to get some input as most of my engines are at the stage that minor adjustments is all that's left to do.
 

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There is such thing as too close and too far a gapping...The optimal gapping between the coil and flywheel is .020"....New laserjet business cards are between .010 and .012"
 

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Discussion Starter · #3 ·
Thanks CAMagedon :) One other quick question for debate.

Piston tops. I've bought pistons that have smooth almost mirror finishes and I've also go ones that are rough like pebbled effect to them. Which is better ? I've heard that a rough top helps with atomisation but wouldn't a smooth top allow for better and accurate compression / squish calculation ?
 

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Thanks CAMagedon :) One other quick question for debate.

Piston tops. I've bought pistons that have smooth almost mirror finishes and I've also go ones that are rough like pebbled effect to them. Which is better ? I've heard that a rough top helps with atomisation but wouldn't a smooth top allow for better and accurate compression / squish calculation ?
The pebbled finish is slightly better to help with the even ignition and transferrence of the flame kernel across the piston top slowing the flame down towards the cylinder wall keeping the heat away from the rings but collects carbon faster than the smoother topped piston which is the top I prefer because the high compression mixed with the high revs I run these engines at so it doesnt really matter because of the squeeze being so tight the kernel has a very tight-tight area to be bern-in to begin combustion and the added carbon build-up on my pistons would be a problem with the squish I have my engines set at which is considered the danger zone ..
 

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Discussion Starter · #5 ·
Genius, Thanks CAM2. I've just bought a few pistons to replace some mishaps with my engines. I have 2 engines with identical hardware out of commission at the moment needing new pistons so maybe I'll try both. Thankfully neither had damage to the cylinder or cases.
 
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