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!
how to plug chop
- Thread starter little3mil
- Start date
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.
What do you cut the threads with?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"
hope this helps B)
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.
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.
Sorry about that I assumed you had the tool. You will need a special wrench. Motion pro makes them or if you have a welder you can make your own. It is a box wrench that you can attach a torque wrench to. Do not NOT torque them to specs.
There is a little math when using the wrench, (don't know off the top of my head.) Ill find it.
Edit: here ya go. http://www.motionpro.com/motorcycle/partno/08-0134/
Or http://www.ebay.com/itm/Motion-Pro-...tor-/321510289945?hash=item4adb81b219&vxp=mtr
There is a little math when using the wrench, (don't know off the top of my head.) Ill find it.
Edit: here ya go. http://www.motionpro.com/motorcycle/partno/08-0134/
Or http://www.ebay.com/itm/Motion-Pro-...tor-/321510289945?hash=item4adb81b219&vxp=mtr
Last edited:
Ok i'll order that wrench, I have a torque socket wrench here, but don't torque to specs? is it 20 ft pnds?
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.
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.
^^^those are all the same plug idk why it posted it 87 different times
What do you think about my plug?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"
hope this helps B)
Attachments
Similar threads
