Another Jetting Question

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SilentCarl
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Another Jetting Question

Post by SilentCarl » 09:54 am Jun 21 2019

Sorry in advance for asking additional jetting questions.

It seems I may have something strange going on. 2000 KDX 200.

35mm airstriker. #6 slide. 158 main 42 pilot DEL Needle 3rd clip. Air screw about 1.5 FMF Woods pipe. Snorkel removed. Holes drilled in airbox lid. 40:1 spectro synthetic 93 octane pump gas.

riding around 2500 ft and 75 degrees 65% humidity.

Did a plug chop on a new plug and it reads a little lean. My main jet seems big compared to other kdx owners.

I have quite a bit of oil spooge but my pilot was kinda rich (had a 45 installed) and I have been mostly putting around. Planning on a 162 main for my ride this weekend.

The bike doesn't really like to rev out. Could KIPS function affect the plug reading?

thanks!

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rungrandpa
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Re: Another Jetting Question

Post by rungrandpa » 04:38 pm Jun 21 2019

I don't know if the KIPS affects jetting, but I have found if you remove your main jet, the bike won't rev out. If the main is progressively leaner it will rev higher.
DEL is too rich for my bike.
My bike used to spoog when I ran 45 pilot and 158 main. I presently run a 40 pilot and 152 main with a 1173 needle.
I've spent a lot of time jetting and I'm not saying I have the answers, just telling you what I've done.

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Re: Another Jetting Question

Post by Vossman » 01:18 pm Jun 23 2019

Post a pic of your plug. Did you run the bike for a while before the chop?

SilentCarl
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Re: Another Jetting Question

Post by SilentCarl » 11:23 am Jun 24 2019

I warmed the bike, swapped to a new plug, did 1-6th gear WFO pull and killed the motor. Plug looked almost completely clean but the electrode was white-ish. I'll retest with the 160 main I have installed currently and post a picture.

Maybe I am just rich and not reading the plug correctly.

My near future plan is to inspect / clean / replace if needed: the powervalve, top end, and install a RB modded head.

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Re: Another Jetting Question

Post by KDXGarage » 07:25 pm Jun 24 2019

Are you reading the base of the ceramic?
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Re: Another Jetting Question

Post by John_S » 12:02 am Jun 25 2019

Here are some pictures of plug chops if it helps reading your plug. These were all done with 1st to 4th gear wide open because I didn't have space to run 5th and 6th. The engine was at operating temp and they had two runs on each plug, one run away from the truck pulling in the clutch, turning around and then 1st to 4th again back to the truck, this time pulling in the clutch and killing the engine. This was on a Honda 250 but I went through the same thing with my KDX, starting too rich and working down. None of these main jets made the bike stutter rich but the 150 made it so run so much better and have about 2000 more max rpms. A huge difference.

Heres a 160 main
160.jpg
160.jpg (37.31 KiB) Viewed 409 times
Heres a 155 main
155.jpg
155.jpg (31.14 KiB) Viewed 409 times
Heres a 150 main
150.jpg
150.jpg (34 KiB) Viewed 409 times
The 150 main picture is what your looking for. A 148 would've probably been perfect dark tan colored. I've never had good luck looking down into the plug even with a light and magnifying glass. These were cut off with a grinder. If you're going to do multiple plug chops a 5/8" bi metal hole saw bit on a drill makes the job MUCH quicker.
IMG_2653.JPG
IMG_2653.JPG (1.67 MiB) Viewed 409 times
The whole ceramic ends up pulling out like this after about 10 seconds with the drill
IMG_2335.JPG
IMG_2335.JPG (225.22 KiB) Viewed 409 times
These plugs were from my 02 KDX 220. The bottom plug is a main jet chop, the middle plug a 1/2 throttle chop (3rd clip down on the needle), and the top plug had 25 hours on it. I like how on the top plug you can still see the 3 different circuits, the main jet (too rich), the needle (almost there), and the pilot (good). For my type of riding (slow to mid speed trail) the needle clip in the 2nd position and a 148 main have the best throttle response, the plug looking dark tan all the way down and no oil running down the silencer.

I did all this while my back was too hurt to really ride but i couldnt resist being out there. One thing I didn't expect to see such an improvement on by doing this was the fuel consumption, it made a night and day difference to the hours of run time per tank (over 5 hours now). It used to go through a tank in a couple hours. I really think its worth the time and effort to follow the jetting guide listed on this site.

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Re: Another Jetting Question

Post by KDXGarage » 04:02 am Jun 25 2019

Wonderful post still!
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Re: Another Jetting Question

Post by SilentCarl » 07:05 am Jun 25 2019

Wow, Thank you John and everyone else.

I don't think I have enough run time on the plug chop. The ceramic looks new (without cutting it apart like you have done). it is just the electrode that has a white-ish color to it.

I will move to a larger space and make doubly sure I have topped out 6th. It may be a few days before I can update as I am working on my truck and have an upcoming track day that I need to prep my track bike for.

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Re: Another Jetting Question

Post by KDXGarage » 08:03 am Jun 25 2019

On a wide open plug chop, a new plug is used each run.
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