I need help adjusting the jet on my bike

trist007

Member
Oct 3, 2007
105
0
I called the KTM dealership and told them my situation. They said to keep the new jets in but to replace the red needle (from JD Jetting Kit) to the PT needle that they had put in and to put in the clip on the 1st notch. I did that, cleaned the plug and now the bike works great. The engine isn't revving up automatically on idle any more, the power is where it should be, and it recovers from quickly opening the throttle like it's supposed to instead of nearly dying the way it was before. However, I do have one concern. I've been using the same plug, mind you this is the first plug, I have about 130 miles on it. However, it's fouled like 5 times. I just take it out, spray brake fluid and clean it with a wire brush. Well after this last time, I think it fouled again, cause I couldn't get the engine started again. The KTM ppl were telling me that once a plug fouls once, it degrades very quickly after that. Is that really true? I mean, thought u just needed to clean it up a bit with a wire brush, and that it doesn't degrade until the porcelain part starts shrinking or degrading.
 

trist007

Member
Oct 3, 2007
105
0
but do you guys think my bike is still running too rich? I mean I dropped down to a 175 main from a 180 and to a 42 pilot from a 48 and put the notch on an even leaner needle to the 1st position, isn't that way leaner than before? I mean my plug shouldn't foul so easily anymore right? I'm hoping it's just a new plug that I need. The only reason I think that my bike is still too rich is that I clean the plug, turn it on once, works great, turn it off, and can't turn it back on again. I then take a look at the plug and it's all black again. I have the air screw out about 1.75 turns. I live in San Antonio which is about 690 ft.
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
The air screw says your pilot is close. Try the needle leaner. How does it run on top? The cold start jet, is that the same as an ap jet? Assuming the filter is clean, and the oil ratio is correct, premium fuel from a busy gas station. With a new plug, run it on bottom and work your way to full throttle, doing plug chops, and see where the plug is getting wet from?
 

trist007

Member
Oct 3, 2007
105
0
Just got my new plugs in the mail. Could someone give me a step by step procedure on plug chops, I'm thinking I just have to get the throttle to a specific section and then just cut the kill switch. Do I keep the gas on as I kill it? Clutch in? Also, could someone plz list the throttle sections that each component and jet is responsible for. I'm guessing the needle and air screw is 0-1/4 throttle, pilot is 1/4 to 1/2 and main is 1/2 to WOT.
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
Kill it, clutch in, throttle off, in one motion. The pilot is the air screw. The needle comes a little after the idle, 1/8 th of the total span. Put basic masking tape on the throttle housing, put an index mark on the outer grip, mark on the tape closed and open. Then just keep divided the spaces in half. The main you will have to either cut the plug for viewing, or trust your judgment with trial and error. The pilot and needle go pretty far into the rpm's, and the main comes in before wide open, they overlap, nice smooth transitions. Jap bikes have nice diagrams for reference on each specific bike. And I do not know what that cold start jet effects, other than the obvious?
 

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