Anyone running a 142 main?

TAT2 · Post by **TAT2** » 05:00 am Oct 16 2014

Hey all,

Anyone run a main as small as 142 with the stock carb? Full FMF pipe...

Trying to clean up my jetting on a bike I just got and it's running rich mid to top. It's already got a 142 main and I had to move the clip to position 1 to dry out the plug. It came to me with a FMF header and pipe and the air box lid off. I live at 1200 agl. FMF recommends 145-148? But it sounds like I may need to go to a 140? I appreciate any insight.

T

diymirage · Post by **diymirage** » 05:06 am Oct 16 2014

i don't think a 142 is unheard of, my 220 runs a 145 main, 42 pilot
as long as you went through the process of jetting it properly i wouldn't hesitate running a 142

TAT2 · Post by **TAT2** » 06:41 am Oct 16 2014

Thanks! I still need to get the pilot out. I went though the jetting procedure from here and I am running the air screw 1 and 1/2 to 3/4 out. But I still want to see what it is. I tried to access it from the bottom of the carb with the main but I had a hard time getting a screwdriver in there to get it out???

I also would like to post a plug picture.... It looks pretty brown to me now. It was grungy and wet and oily with the clip in position 3 and then 2. Just afraid of it being too lean.....

T

TAT2 · Post by **TAT2** » 12:35 am Oct 17 2014

I leaned my clip position out to clean up the plug and got this.....is this the "brown" I am looking for?

Sorry..... But I am new the the plug reading gig ..... Thanks!

T

diymirage · Post by **diymirage** » 07:23 am Oct 17 2014

looks good to me

ideally you would cut the thread of to see the color in the electrode but it looks pretty decent from what I can tell

G22inSC · Post by **G22inSC** » 08:18 am Oct 17 2014

Just as an example...

You want to be looking below what you would see if the threads were still in place.

IDRIDR · Post by **IDRIDR** » 10:37 am Oct 17 2014

Nice to learn something new about cutting the threads. What does this one ^ tell you? White and lean?

TAT2 · Post by **TAT2** » 11:08 am Oct 17 2014

G22inSC wrote:Just as an example...

You want to be looking below what you would see if the threads were still in place.

Thanks. I thought I was just looking as far as I could down into the plug electrode. But am I really doing plug chops and then cutting off threads? And if so.....how are you cutting off the threads?

What does the plug you show tell me? The brown ring?

Sorry about all the stupid questions....

T

200Green · Post by **200Green** » 01:09 am Oct 18 2014

g day bloke dude your jetting/main is way to lean plug should look choc brown looking at your plug its not. downunder/hear recommended and tested 152main and idle jet 42 and or 43 but if you are a heavy bloke/dude run it recher 155 main idle jet 45 hope this answers your question. ah and btw is your front suspension still stock? get reed of it and get some kx 125/kx 250/klx 250 front end dude you going to love it.
enjoy your green machine.

TAT2 · Post by **TAT2** » 02:34 pm Oct 18 2014

Thanks for the advise. 145 is stock for a 220.

G22inSC · Post by **G22inSC** » 05:29 pm Oct 18 2014

TAT2...yes you really are doing a single plug chop and then cutting the threads. My earlier pic was just an example of cutting away the threads (Dremel or hacksaw) to get to what you need to see. I have come to the conclusion that plug chops aren't the end all after some testing I did. Keep in mind my KDX is a 200 so the main jet numbers will not coincide with yours.

These were single drag runs holding wide open as long as possible (don't remember the gear), pulling clutch as killing the engine, coasting to a stop, pulling the plug, inserting and old plug and going back to the truck to change jets. I never saw much difference and then was told by several sources in the know that plug chops don't work like they use to because of today's horrible fuels. I just jet my main until its definitely rich and then back off a little. Just my opinion anyways.

G22inSC · Post by **G22inSC** » 05:31 pm Oct 18 2014

200Green wrote:g day bloke dude your jetting/main is way to lean plug should look choc brown looking at your plug its not. downunder/hear recommended and tested 152main and idle jet 42 and or 43 but if you are a heavy bloke/dude run it recher 155 main idle jet 45 hope this answers your question. ah and btw is your front suspension still stock? get reed of it and get some kx 125/kx 250/klx 250 front end dude you going to love it.
enjoy your green machine.

Those are typical 200 numbers but TAT2 is working on a 220.

TAT2 · Post by **TAT2** » 06:10 pm Oct 18 2014

G22....thx for the great pic!! I am going to try a new plug with what I have set up now except maybe go down to 2 on the needle to richer it up a hair. I may go buy and try a 145 main too.

I am having a hard time getting at the pilot jet from the bottom of the carb? Am I missing something? How or where else would you access the pilot? Sorry....noob....

Oh.... And what is the gap on the plug? I really need a manual......

T

G22inSC · Post by **G22inSC** » 06:33 pm Oct 18 2014

200 gap spec is .028 to .032 inches. Easiest way to get the pilot is to turn the carb (loosen the boot clamps) and then remove the float bowl. I've never tried to get to the pilot through just the bowl drain.

edited to give the true plug gap specification

TAT2 · Post by **TAT2** » 12:50 am Oct 19 2014

G22 thanks! I will get the pilot out to see what's in there.

T

G22inSC · Post by **G22inSC** » 05:45 pm Oct 19 2014

I went and checked my manual (for a 200 but I doubt it would be different for a 220) and it shows a gap spec of between .028" and .032". I'm sure someone here has a true 220 gap spec who could verify if there are the same.

TAT2 · Post by **TAT2** » 07:33 pm Oct 19 2014

G22.....Thanks brother! You rock! Gunna work on the bike tomorrow on my day off!

T

TAT2 · Post by **TAT2** » 11:26 am Oct 20 2014

G22inSC wrote:TAT2...yes you really are doing a single plug chop and then cutting the threads. My earlier pic was just an example of cutting away the threads (Dremel or hacksaw) to get to what you need to see. I have come to the conclusion that plug chops aren't the end all after some testing I did. Keep in mind my KDX is a 200 so the main jet numbers will not coincide with yours.

These were single drag runs holding wide open as long as possible (don't remember the gear), pulling clutch as killing the engine, coasting to a stop, pulling the plug, inserting and old plug and going back to the truck to change jets. I never saw much difference and then was told by several sources in the know that plug chops don't work like they use to because of today's horrible fuels. I just jet my main until its definitely rich and then back off a little. Just my opinion anyways.

This pic just got me thinking. Are you just leaving your clip in position 3 on the needle and changing main jets to get a top end? Then do you tweak your clip position?

I just changed clip position to dry the plug out.....?

Always what jet did you go with based on these pics? The 158 and 160 look rich I guess. 155?

Thx

T

G22inSC · Post by **G22inSC** » 12:39 pm Oct 20 2014

That was some old testing. I'm currently running a DEL-3 with a 42 PJ and 155 MJ. Meant to try a 40 PJ this summer but never got around to swapping out brass.

TAT2 · Post by **TAT2** » 12:55 pm Oct 20 2014

G22inSC wrote:That was some old testing. I'm currently running a DEL-3 with a 42 PJ and 155 MJ. Meant to try a 40 PJ this summer but never got around to swapping out brass.

Where are you running the clip for testing? Position 3 ?

I need to get my pilot out to see what it is. It may be causing my rich issues. But I am running 1.75 turns out on the air screw.....

T

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