Hows My Jetting?

[BIGFOOT16]

Just put some Boyesen power reeds and a 142 main in my 2001 220.Needle is 2nd from top,pilot is 42,a/s is 1 turn out.I have stock exhaust/silencer.It also has uni air filter and lid removed.The temp. today was about 90 F.humidity same.Seems to run very good.Am I in the ballpark,or too lean in the main?Will attempt a WOT reading Sunday.

 

[Canadian Dave]

That's about what I'd expect to see given your riding conditions. Your plug reading will confirm if your main is approperately sized. I expect it will be a tad rich if anything which is where most people like to be.

David

 

[BIGFOOT16]

Thanks for the response,Dave.I have read your jetting article in JustKDX several times.What I still don't get,though,is why a WOT test.If a person is an average rider,like myself,wouldn't you be better off using basic jetting recommendations for starters and take a plug reading after say a week or so of normal riding?It just seems that this would give you a better idea of where your jetting is at for your general conditions.

 

[Fred T]

I did the same 2 weeks ago.

The only difference is that I'm running the FMF rev pipe and the 142 main looked a bit lean to me when I did a WFO plug chop so I switched back to the 145 and it ran like a bear that weekend. I have all other settings the same as you but I'm not exactly sure where the A/S is.

When you gonna git that rev pipe?

 

[BIGFOOT16]

I can't decide between rev or torque.Don't want to end up with KX like power.I've also read too many horror stories about the stock piston and hop ups.I figured,I would ride this year and try a pipe next year.

 

[Baked]

Bigfoot,
I've had the gnarly and the Rev... If you don't have anything else done to your bike... it won't matter. If you're a beginner rider the pipes will feel about the same. I prefer the Rev just for the fact that as you progress in skill you tend to whined (sp) the bike up a little more. TOP PRIORITY FOR YOU should be to change the stock piston. This is not a fairy tale... I didn't hear about it and CRUNCH, the thing just broke. It chipped on the skirt. That sucked... ended up spending about $700 because the bottom end had to be split, cylinder resleaved and a few other things. But back to the pipe issue. Get the Rev, if you don't like it, stick a torque ring in there. That's my opinion! ;)

 

[spanky250]

Originally posted by BIGFOOT16
Thanks for the response,Dave.I have read your jetting article in JustKDX several times.What I still don't get,though,is why a WOT test.If a person is an average rider,like myself,wouldn't you be better off using basic jetting recommendations for starters and take a plug reading after say a week or so of normal riding?It just seems that this would give you a better idea of where your jetting is at for your general conditions.

A WOT plug-chop test is only useful for checking the main jet. Plug color is a very poor indicator of proper jetting at less than WOT, it only really tells you if the heat range is correct. You check the pilot and needle circuits by feel and response.

 

[Fred T]

Originally posted by Baked
Bigfoot,
TOP PRIORITY FOR YOU should be to change the stock piston. This is not a fairy tale... I didn't hear about it and CRUNCH, the thing just broke. It chipped on the skirt. That sucked... ended up spending about $700 because the bottom end had to be split, cylinder resleaved and a few other things. But back to the pipe issue. Get the Rev, if you don't like it, stick a torque ring in there. That's my opinion! ;)

How many miles did you have on the bike before it let go?

 

[BIGFOOT16]

Fred T;I don't know if you were addressing me or BAKED.My KDX has 153.7 miles on it.I know,cause I just got in from a ride.

spanky250;Thanks for the helpfull info!!

Just wanted to mention;The boyesen reeds did exactly what I wanted.No arm ripping power,but better low end response.Almost like my old four stroke!!

 

[andrew]

Originally posted by spanky250
A WOT plug-chop test is only useful for checking the main jet. Plug color is a very poor indicator of proper jetting at less than WOT, it only really tells you if the heat range is correct. You check the pilot and needle circuits by feel and response.

I'm with you, Spanky. My plug looked nice and brown when riding it below WOT, but it seemed to be "running on" at WOT under load. I went up to a 148 main (from 145) and the problem disappeared (see my separate post)
It makes me wonder how others can run 142's and not have that problem.

 

[G. Gearloose]

Andrew, those small jets are entirely a '220' thing.

To be in the low-mid 14X range on a 200, one would likely be really high in elevation, or still running stock airbox lid, or riding an SR.