92 kdx250

[terbo]

i have a 1992 kdx250 and when i ride black crap shoots out of the silencer and all over my swing arm. i run 50to1 through it with 93 octane and race oil from a local shop but the kid i bought it off of (i bought it about 3 monthes ago) beat the crap out of it and i was wondering if that had anything to do with it. i think its the jetting , but im not sure. its torn apart right now and i was wondering (if the jets are the problem) what size i should get.

 

[43Duc748]

I don't know where you are riding (elevation wise), but the following are my setting for Californias High Deserts (2 - 3k feet?)

Needle: 1367 (middle clip I think - can't remember exactly)
Pilot jet: 38
Main jet: 155
Boyesen Power Reeds
91 octane at 40:1 w/ Yamalube Y-2R

I tried other oils, but they all spooged much more than the Yamalube.

 

[roadstar_rider]

might try repackin the silencer as well
155-main
40-pilot
neddle 2nd from top here in the mountains of east tennessee

 

[terbo]

how would i figure out what size jets and needle i have

 

[dirt bike dave]

Not sure what you have in there now - you would have to take it apart and check.

Your stock jetting is HORRIBLY RICH and was:

Needle: R1368
Main: 165
Pilot: 42
Slide Cutaway: 5mm


You can view microfiche for your bike at www.buykawasaki. com No sure if this will work, but the carb fiche is here: https://www.kawasakiepc.com/SystemS...=Model&cGroupID=&CFID=787170&CFTOKEN=71885019

In addition to leaning out the jetting as recommended by the previous posters, you can also replace the slide with a 6mm cutaway, or carefully grind about 1mm off of the bottom of your stock slide.

Rejetting your bike will make it run much better and reduce the spooge. Another cheap trick is to use a head gasket from an '88 KX250. This will raise the compression some for more low end power, and the bike will still run fine on pump premium fuel.

 

[terbo]

Not sure what you have in there now - you would have to take it apart and check.

Your stock jetting is HORRIBLY RICH and was:

Needle: R1368
Main: 165
Pilot: 42
Slide Cutaway: 5mm


You can view microfiche for your bike at www.buykawasaki. com No sure if this will work, but the carb fiche is here: https://www.kawasakiepc.com/SystemS...=Model&cGroupID=&CFID=787170&CFTOKEN=71885019

In addition to leaning out the jetting as recommended by the previous posters, you can also replace the slide with a 6mm cutaway, or carefully grind about 1mm off of the bottom of your stock slide.

Rejetting your bike will make it run much better and reduce the spooge. Another cheap trick is to use a head gasket from an '88 KX250. This will raise the compression some for more low end power, and the bike will still run fine on pump premium fuel.

thanks alot i kinda thought it was the jets but i didn tknow where to start

and how bad could i mess up my slide/bike if i didnt grind it down right or more that i was supposed to

and will i have to get different jets when i get a gold series fatty

 

[dirt bike dave]

Most people will not mess with the slide mod. The bike will really respond to the other jetting changes, so you should do them first. If you decide to alter your slide, scribe a line 1mm up from the edge all the way around, and grind almost up to your line.