liven07

Member
Mar 29, 2009
46
0
Anyone know what the stock jet sizes are on a 87 kdx 200. I don't think the number stamp'n machine was working very good that day, i can barley see the numbers. I rebuilt the engine with a 220 rod and it's putting out 11.5 to 1 or compression so i need to rejet.
 

dirt bike dave

Sponsoring Member
May 3, 2000
5,349
3
You can find parts diagrams at www.buykawasaki.com which is the official kawasaki website. I checked there and it looked like the same.

FWIW, those older jets were measured differently than what they use now, so an '87 320 main is not going to be that much bigger than a 155 or 160 from a newer bike.
 

liven07

Member
Mar 29, 2009
46
0
I went to the shop after work. I got a 330 they had about 50 sizes, ran better but not good think I'm going to try a 360.
 

dirt bike dave

Sponsoring Member
May 3, 2000
5,349
3
Did you increase the displacement to 220?

FWIW, when I went to a 240 big bore on my '84, LA Sleeve recommended very rich jetting. Eventually, I found it ran best just a little leaner than stock.

Basically, the increased displacement sucks in harder through the same size carb venturi, so it brings in more gas for the same volume of air.

Before you put in a 360, I'd try your stock 320 and see if it works better than the 330 you bought. You might eventually end up at 310 or less.
 

liven07

Member
Mar 29, 2009
46
0
When I bought the bike the main bearings were out so I gave it a rebuild, chunks of main bearings destroyed most everything in the engine. Anyways I bought a rod kit and it turns out there is a misprint in parts unlimited catalog and they sent me a 220 rod, since I already had it and had all winter to work on my engine I compared it to my other rod and the only difference is that it is about a 1/8 in.(forgot the exact measurement) longer than a 200 rod, so right a way I thought more compression, so I used it. I had to fab 2 16 gauge spacer for the bottom of the cylinder, I made three but ended up using only 2 spacers and 2 gaskets to get the compression I wanted. The bike runs good just seemed like a little slugish off the start and I think I might know why when I was just changing these jet I found that it had a 30 pilot jet, stock is 25, this seems like a big jump for a pilot jet maybe getting to much fuel at low rpms. However the 330 main jet I put in, I could definitely feel more power. I'm going to switch that pilot jet and see what happens when I go back to the parts store I'll buy a 310 and a 340 give em both a try, it's kinda weird someone would change the pilot jet 5 over and not the main in a what was before a stock bike.
 

bigbolx

Member
Dec 25, 2007
30
0
86 C1 = 300 main jet, R-4 needle jet, 35 pilot jet
87 C2 = 320 main jet, R-2 needle jet, 25 pilot jet
 

liven07

Member
Mar 29, 2009
46
0
Dirt bike dave you were right on the jets. I notice that oily gas was coming out the exhaust and the bike was losing bottom end power the higher jet i would put in. It would flood the bike until the kips open then it would take off screaming.300 main did the trick. Thanks for the info.
 
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