[02'400ex]

So I just traded straight up a Yamaha Kodiak for my now 2002 400ex. I was told that it was bored to a 440. I have a few problems. It does not want to run without choke, and even then, it wants to die unless I give it a lot of throttle when shifting into gear. Also, I noticed that the carb is leaking gas. So, I purchased a carb rebuild kit today, as well as new jets (185 and a 42) thinking that maybe the jets were never swapped. Also ordered a maintenance kit. It will run fine, but after driving down the street and back a bit, I noticed some smoke coming out the exhaust, I'm guessing its running too rich since the choke has to be on.

Anybody have any advice, and does it sound like I'm on the right track?

 

[Goober]

Check your plug—if it’s really dark good chance your too rich.
I don’t know anything about your rig, but if it has a carb maybe you can adjust the AFR with the pilot jet.I don’t know about your choice of jets either.
After engine warm up. Turn in pilot jet til engine stumbles or quits; turn back out 1/4 to 1/2 turn. You may have to slightly adjust idle screw

 

[alloutdoors]

You are certainly on the right track, i.e., carburetor challenge. As for the carburetor, I would only use genuine OEM Honda parts and do not underestimate how clean you need to get everything in there for the unit to run properly. While you are waiting for the kit, I would clean (tank and replace fuel line) and service the unit (spark plug, air filter, oil [wet clutch approved], especially given the age, i.e., 2002. Chances are you can download the service manual here from the technical section, see https://www.hondaatvforums.net/foru...nual-help/50817-service-manual-downloads.html

 

[retro]

I'd check the compression as well, in case the head gasket is blown. Keep us posted if you can.