do the 90-04 KX 500's come jetting to rich (pilot)?

[mattb348]

I have a 2002 KX 500, which seems to be jetted pretty much perfectly. The only mod it has on it is the PC pipe & PC factory sound silencer, which it came with when I bought it.

I suspect that it still has the stock jets in it, but I haven't checked yet.

I tested it at all different throttle openings, and it seems to run perfect; no crackling or bogging or anything, none of the red flags. I still have to do a WOT plug chop though.

My question is this: do the 2002 KX 500's come with a rich pilot jet like the 250? Becuase the 250 pilot jet is like 4 sizes to rich! I suspect it may be to rich because the pipe has alot of oil all over it, way more than my 250 ever did.

It hasn't fouled a plug yet while warming up, which is something my 250 did like every 3 times you cold-started it, but I really haven't started it enough times to be able to tell if it is going to cold foul a plug yet.

Thanks for any info guys!

 

[rob129]

Check this out..........
http://www.maximausa.com/technical/lubenews/springsummer2001.pdf

 

[KX02]

Yeah, that's an excellent read and shows how to quickly tell if your pilot is in the neighborhood or not.

 

[91kx]

Mine runs significantly better now that I switched from the stock 60 to a 52.I also changed to a r1370n needle from a CR500.It always seemed to blubber from low to mid even with the smaller pilot with the stock needle(n82m).Racetech recommended the r1370n for the kx.Makes a nice difference.$13 CDN from my dealer.

 

[rob129]

I run a 1470 needle in my 89 CR500...I have a PWK 39.5mm on there, same as on your KX500. It leans out the bottom and fattens up the mid/top a hair. I have also heard a 1468 is a good needle. FYI the jets between the PWK and PJ are interchangeable.