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Old 07-16-2011, 04:55 PM   #1
geezer
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the geezers plug chop!!

first off i would like to explain to you what a plug chop is. plug chopping is another way to tune a carburator to deliver to the engine the proper amount of air and fuel. when an engine is running rich, as in to much fuel inside the motor, your spark plug will look black when you pull it out because its actually unburned fuel or soot actually. this is a waste of fuel and can hurt spark plug life because eventually you will foul it out and the spark will not ignite the mixture properly. now a white plug is an indication that you running the thing to lean. running an engine to lean, or in other words not using enough fuel, can have some very serious side effects. without enough fuel the engine will actually run hotter than usual because fuel not only gives the engine its power but it also acts as a coolant inside the cylinder. so in essence its kinda like running your car low on coolant. if you run lean enough major engine damage will result.

in order to get this air fuel mixture spot on where it needs to be you need to use the plug chop method or an exhaust analyzer. well i dont have one of those lol :lol: so in order for me to tune the bike ill plug chop.
you can do this on your bike stock or modified. but im doing it because i have added a high flow airfilter and muffler. so what do you think i just did to my air/fuel ratio? i leaned it out because now the engine canget more air in so i need to add more fuel now too.
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Old 07-16-2011, 05:03 PM   #2
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Re: the geezers plug chop!!

you must start by doing the open throttle circuit first (MAIN JET) so after gettng the bike warmed up on the old spark plug, shut it down and remove the bolts holding the tank down and remove [attachment=1:1pi3cbgh]DSC09762.JPG[/attachment:1pi3cbgh]the engine shild covering the spark plug. remove the old one and put in the new properly gaped one (.024-.028in) then push bike out to the street and once youve got a clear shot start it and go WIDE ASS OPEN! ride it like you stoll it for as long as you can, then hit the kill switch and stop. remove the spark plug and inspect.[attachment=0:1pi3cbgh]DSC09763.JPG[/attachment:1pi3cbgh] mine was still looking lean and i already installed a 136 main jet so now i gotta get me a 140 and retest. i cant move on till i finish with the main jet so

to be continued... i hope i did a good job i aint much of a teacher lol if you got questions or im wrong about someting let me know
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Old 07-16-2011, 05:24 PM   #3
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Re: the geezers plug chop!!

reason i removed the tank bolts was to make removing the spark plug easier so that way you could lift it up a bit to fit your 18mm socket extention and rachet in there. also dont even come close to torquing the test spark plug! remember this is a hot engine and the threads will be more than happy to strip fo ryou! just alittle more than finger tight will work for the small amount of time its in there. it took me a few passes to finally get a defenate white mark on my plug so do the chop as many times as you see fit. remember fire it up got wide open as long as possible then kill switch it off withought leaving ful throttle.
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Old 07-16-2011, 10:38 PM   #4
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Re: the geezers plug chop!!

I would think a steady speed of 60 mph would be more representative in everyday riding. Better results would also happen if you are able to shut the throttle, kill the engine, pull in the clutch at the same time and coast to a stop. Not always possible but give it a try if able.
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Old 07-16-2011, 11:24 PM   #5
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Re: the geezers plug chop!!

Quote:
Originally Posted by Water Warrior
I would think a steady speed of 60 mph would be more representative in everyday riding.
A steady speed will only check your mid-range,which is controlled by your needle jet,which will tell you if you need to shim it (raise it) to be richer,or lower it to be leaner.Your idle to 1/4 throttle mixture is controlled by the pilot jet. ( Idle mixture jet).You use same procedure,just different throttle position.
:cool:
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Old 07-16-2011, 11:34 PM   #6
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Re: the geezers plug chop!!

Quote:
Originally Posted by geezer
remember fire it up got wide open as long as possible then kill switch it off withought leaving ful throttle.
30 seconds to a minute is plenty to get a reading.In case you are running lean, you don't want to cause any damage.
:cool: :2tup:
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Old 07-17-2011, 04:32 AM   #7
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Re: the geezers plug chop!!

sounds right blain, i had to ride the bike back and forth 4 times to get a good reading from the plug. looks like im going to try a 140-145 mainjet and i really think thats gonna do it. on the highway tonight it was really having a hard time keeping speed and i bet its cause the cold air is making it run even leaner. i cant wait to see what hapens
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Old 07-17-2011, 04:38 AM   #8
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Re: the geezers plug chop!!

btw water warior, like blain said. the purpose of a plug chop is to see what the engine is getting at one specific throttle angle, not engine speed or vehicle speed. at wide open the carb is using mainly the main jet so thats how you tune just the main jet
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Old 07-17-2011, 02:36 PM   #9
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Re: the geezers plug chop!!

Quote:
Originally Posted by geezer
btw water warior, like blain said. the purpose of a plug chop is to see what the engine is getting at one specific throttle angle, not engine speed or vehicle speed. at wide open the carb is using mainly the main jet so thats how you tune just the main jet
I stand corrected. Using the main jet makes more sense than my idea.
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Old 07-17-2011, 02:55 PM   #10
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Re: the geezers plug chop!!

oh dont worry im just readin this stuff off the internet myself
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