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.
 
there is a very fine line way of doing this to tune your motor in perfect.

start your bike, warm it up and ride down the street with a plug socket and a brand new plug in your pocket, stop, pull the used plug out, put the new one in, (now heres where people mess this process up) start it up and go 1st through atleast 5th WOT and when you hit 5th full blastyz cut the motor off and pull in the clutch, roll to a stop and take the plug out. now what you want to do is put the plug in a vise and cut the threads down almost to the bottom like the picture shows. the picture is my trail blasters plug chop at full throttle, it is perfect cant get any better than this, you want a nice and clean plug (not wet or black obv.) the strap should look like mine (almost no color very faint brown) and the light brown ring should be around the electrode, remember 1 pull thats it! its the only way your going to get dialed in perfect and be able to ride "worry free"

2nkj8tz.jpg


hope this helps B)
What do you cut the threads with?
 
What do you cut the threads with?

i don't cut the threads, i use a good flashlight and a magnifying glass to veiw the smoke ring.
but if you'd like to waste a plug, use a hacksaw and vise to hold the plug while you cut
 
My blaster is fully stock, only thing that has been changed is I removed the Oil injection pump. bought a standard 66MM piston rings and brand new cylinder. Once I install everything before I run it should I do any adjusting to my carb because of the oil pump removal?
 
Before you start it you must leak test, to make sure that it is airtight.

Heat cycle and re torque the head and cylinder.

Run 2 tanks of fuel through at no more than 3/4 throttle, then plug chop to confirm your jetting.
 
Yes. Then after heat cycles re torque. seems like allot but its not really. Do it right or do it over..
 
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For the head is 20 ft lbs and the base (cylinder) is 18 ft lbs. When you use the adaptor on the end of the torque wrench you need to adjust the torque wrench to compensate for the xtra leverage of the additional length. I posted a link that shows you the math needed..

Example. If the desired torque needed is 18ft lbs

Design Variables
Desired (Applied) Torque (T) lb-in = 18ft lbs
Lever Length (L) in = 15"
Extension Length (E) in = 4"
Results
Indicated Torque (Y) lb-in = 13.5ft lbs
So you would need to set torque wrench to 13.5ft lbs to achieve your 18ft lbs.

Yours may be different depending on the length of your torque wrench and the length of the adaptor wrench. See link for proper measurement reference points.
 
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7BDC9E40-CCC4-44A9-B0D1-4525B690DA66.jpeg
FCDCBAEA-83E3-4057-BC8B-147DD8C3700E.jpeg
FCDCBAEA-83E3-4057-BC8B-147DD8C3700E.jpeg
how does this look? i need to retune as i tuned to bike during winter but this plug chop is from when i last tuned it.
7BDC9E40-CCC4-44A9-B0D1-4525B690DA66.jpeg
 
View attachment 35422 View attachment 35423 View attachment 35422 View attachment 35423 View attachment 35423 how does this look? i need to retune as i tuned to bike during winter but this plug chop is from when i last tuned it. View attachment 35422
View attachment 35422 View attachment 35423 View attachment 35422 View attachment 35423 View attachment 35423 how does this look? i need to retune as i tuned to bike during winter but this plug chop is from when i last tuned it. View attachment 35422
^^^those are all the same plug idk why it posted it 87 different times ‍♂️
 
there is a very fine line way of doing this to tune your motor in perfect.

start your bike, warm it up and ride down the street with a plug socket and a brand new plug in your pocket, stop, pull the used plug out, put the new one in, (now heres where people mess this process up) start it up and go 1st through atleast 5th WOT and when you hit 5th full blastyz cut the motor off and pull in the clutch, roll to a stop and take the plug out. now what you want to do is put the plug in a vise and cut the threads down almost to the bottom like the picture shows. the picture is my trail blasters plug chop at full throttle, it is perfect cant get any better than this, you want a nice and clean plug (not wet or black obv.) the strap should look like mine (almost no color very faint brown) and the light brown ring should be around the electrode, remember 1 pull thats it! its the only way your going to get dialed in perfect and be able to ride "worry free"

2nkj8tz.jpg


hope this helps B)
What do you think about my plug?
 

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