2003 Kawasaki bayou 250 carb problem

[dkgg5755]

This thing came with a cheap aftermarket carb on it the problem I'm having is it won't start with choke installed into carburetor it will start and get run without it installed then bogs out after about 2 min run time I've checked timing , compression, checked valves for proper clearance , also did a smoke test for air leaks found none. 

[Gwbarm]

The aftermarket carbs come with their own plunger which is a little different from the OEM one if it wasnt installed when the carb was put on that could be your running problems, if the choke plunger is too long or to short, you could either be to rich or to lean. You could try putting the choke in part way no screw all the way down and see if that makes a difference.

[dkgg5755]

Tried just putting choke in carb not screwing it down immediately stops running noticed plug was black fouled it out tried new plug same thing tried 2 different carbs still does same thing. I've checked spark which is consistent not sure if plug is right one maybe that might be the issue.

 

 

 

Edited December 14, 2025 by dkgg5755

[Gwbarm]

Spark plug should be NGK D8EA or compatable. It does sound like it is running very rich. 

[jen]

Sorry Stupid question here... On My Kaw 1000 motorcycle my tech used mercury columns (He was old school but handsome guy) to set my four  (4) Carbs.   agh ..is that applicable here.

[jen]

This is not my 1992  ..don't have pic available on phone...Its a beast at 600 lbs  and 7.5 gal fuel tank. Saddle height is high for my crotch. This one is 1992  but with a lower seat.    He fell over on his kick stand and A guy had to help me get him back up.  Very eembarrasing.😞

 

[bellarmine]

Yes I'd agree sounds like it's running pig rich.  I got a Suzuki Kingquad running nice with a Chinese carb, took a bit to dial it in, but I just used the factory jetting.  Unfortunately you don't know what yours was or should be.  I suppose you've checked the standard items such as the pilot jet screw, and the float level?  They are very important.

[Gwbarm]

No this has one carb. The mercury colums were used on your Kawaski 4 cylinder to sync all the 4 carbs together to make sure they were all doing the same thing at the same time. You can also do it with a vaccum guage  but mercury is more accurate.

[jen]

Oh  OK  I told you it was a dumb question ...AghHHHH 

[Gwbarm]

No such thing as a dumb question! Thats how we learn.

[jen]

Well thanks that was kind of you. 

[dkgg5755]

8 hours ago, bellarmine said:

Yes I'd agree sounds like it's running pig rich.  I got a Suzuki Kingquad running nice with a Chinese carb, took a bit to dial it in, but I just used the factory jetting.  Unfortunately you don't know what yours was or should be.  I suppose you've checked the standard items such as the pilot jet screw, and the float level?  They are very important.

I got the book if I can locate it the woman tends to move things around I can look up correct jetting for it and get it going.

[jen]

HMMM BOOK?   did not followthat

[WeeBee]

I think he's Referring to Shop Manual with Correct Carb Jetting Settings??

[jen]

Oh OK he was saying that his "woman" tends to move things around"....(and he cannot find them) ... LOL..Sometimes I am a little dense...He should keep his manuals in His shop...I keep my manuals in my shop.. with pin ups pictures of hot guys on the wall.  Well only a couple...

[dkgg5755]

18 hours ago, bellarmine said:

Yes I'd agree sounds like it's running pig rich.  I got a Suzuki Kingquad running nice with a Chinese carb, took a bit to dial it in, but I just used the factory jetting.  Unfortunately you don't know what yours was or should be.  I suppose you've checked the standard items such as the pilot jet screw, and the float level?  They are very important.

I got the book if I can locate it the woman tends to move things around I can look up correct jetting for it and get it going.

I got jets ordered and stopping by to pick up new plugs as well 120 Main Jet and a #42 Pilot Jet

 

Don't have a shop as of yet working on that.

 

[dkgg5755]

And yes I was referring to repair manual. 

[dkgg5755]

Sorry for late post on carb problem been busy at work. Finally got time to really look at the carb it ended up the head gasket is blown not sure if it will need a new head or just a gasket as of yet.

[jen]

Glad you figured that out....Gasket blown....????  Hydrolok????  Is rod bent also...?  

[dkgg5755]

Rod isn't bent just looks like gasket came apart and separated from the metal inside it oil is coming out from around the gasket between head and cylinder could have possibly damaged it when installing it 

[jen]

Glad to hear that.   head bolts original?

[jen]

will you plane or check head with feeler gauges for flatness?

[dkgg5755]

Definitely going to do that I have a feeling that head might be a problem I'll just use a straight edge and check it will a feeler gauge to make sure if it needs to be replaced.

[Gwbarm]

Head should be fine unless you see discolored areas from extreme heat, make sure the gasket surfaace is flat and the head fits on with no big gaps if its not perfectly flat you can get some aggresive sandpaper and lay the head on it going back and forth to flatten it back out and replace the gasket do not put gasket sealer on the new head gasket it keeps the head gasket from sealing correctly resulting in failure, maybe not immediately but at some point make sure head bolts aare torqued correctly.