how to plug chop

Thanks for the detailed "how to" plug chop, and all the helpful picks. I recently picked up a blaster and after a few tanks of gas it started running horrible. I checked the compression and only had 100psi. Rebuilt the top end with .040 wise piston and rings ,melted the rings on the first tank following the ken (minus the plug chop) break in precedure. Found some oil behind the generator cover, replaced the crank and every bottoms end seal and .060 cast namura piston. I found I had a 220 main jet. I have done two plug chops and im still lean with a 240 jet, so Monday I'll be upping it a 260. I would have certainly had problems again without all the helpful info Ive found since joining this site. Thanks again!
 
Thanks for the detailed "how to" plug chop, and all the helpful picks. I recently picked up a blaster and after a few tanks of gas it started running horrible. I checked the compression and only had 100psi. Rebuilt the top end with .040 wise piston and rings ,melted the rings on the first tank following the ken (minus the plug chop) break in precedure. Found some oil behind the generator cover, replaced the crank and every bottoms end seal and .060 cast namura piston. I found I had a 220 main jet. I have done two plug chops and im still lean with a 240 jet, so Monday I'll be upping it a 260. I would have certainly had problems again without all the helpful info Ive found since joining this site. Thanks again!

What mods have you got? Pipe? Intake? Airbox cover removed? Aftermarket filter? If you let us know what altitude and temp you're at, we could probably ballpark you. In all likelihood, your gonna need to be up at 280 at least. My neighbor and I just finished jetting his and with a pipe, uni filter and open airbox, he's at 310.

Also, we found that to get a reliable read off the plug, you have to go though all six gears AND you have to go a good 1/2 to 1 mile as well. Since this is not always possible, an alternative is to keep increasing the main until it bogs (starts to lose power) at full throttle and back off a size on the main.

Then, use the throttle limit screw on the throttle lever on the handle bars to limit the throttle to half open and do the same thing again adjusting the needle clip (moving the clip down is richer). This might not give you perfect jetting, but will put you safely on the high side of it and be pretty damn close.

Resist the urge to lean things out further (it will get faster) without doing a reliable plug chop.
 
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so i went from a 310 to a 330. The first 2 pics are the 310, the second 2 are the 330, what do u guys think? i think the 330 might be okay?
 

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wish my buddy would read this but he is to stubborn and would rather keep replacing pistons.. and is to proud to listen to me
 
All look way too lean for my liking.

Have you leak tested, and set the float level.

Do one with a #350.

thanks, seemed to have a small leak in the head, but I doubt that was enough to affect things. sadly I don't have a leak tester.
 
Even a small leak, head, pipe , jug can mislead you into using a larger jet to compensate.

I urge you to leak test before it lets you down.

PM Awk08 about a tester.
 
Even a small leak, head, pipe , jug can mislead you into using a larger jet to compensate.

I urge you to leak test before it lets you down.

PM Awk08 about a tester.

wouldn't any leak be pretty evident from an oily mess near the leak?
 
Hey thanks for the detailed pictures . But wouldn't save a lot of time and plugs just using a digital cylinder head temp gauge ???
 
Also removing plug from a very hot aluminum head could remove threads possibly or even completely seize plug in the threads! I know you are taking the mixture to the finest ratio for the absolute hp,(stokeametric) 14.7 -1 but one extremely low humidity ,high temp day, and some wot rides all the way through 6th gear, for extended lengths of time and good by Blasty Engine