OK you thumper experts, KLX300 question

[AMink]

My neighbor has a 97 Kawasaki KLX 300 with a 330 kit in it. Manual compression release, hot start, and some other nice additions. The thing runs great... when you can get it started. It started on the first kick cold, but then was terribly hard, then impossible to get it going after it warmed up some. He actually bought a Suzuki 400 w/electric start because he got tired of trying to start it in the desert. He had the valve clearances checked, and they were fine. I have read the KLX's have this hard start problem, otherwise are great bike. Does anyone know any secrets to starting this beast? The reason I'm interested is that he's selling it and I can get it for what I think is a good price. Thanks for any advice!

 

[Cummins Pilot]

Sounds like a carb issue from what you have mentioned. Common problem. That particular bike (if the carb is stock, is it?) has a Constant Velocity carb. The throttle doesn't directly control the slide in the carb to determine the fuel air mix. Vaccuum from the engine via ports in the carb (diaphram & chamber) pull open the slide as the engine needs it. Now the problem starting can be an issue with the ilde jet/air screw. Most bikes like this that can run on the road have been hijacked by the CARB people. The carb is tuned to run lean and the idle jet is turned way out (rich) to assist in starting with a brass plug covering the screw making it nonadjustable to most people. I drill out the plug and reset the screw as needed. Now when the engine is cold a rich mixture is a good thing. When the engine is hot it makes it difficult. Now remember how I mentioned the vaccuum developed by the engine opens the slide. Well when the engine isn't running the slide is closed. Little air and lots of fuel make a hot engine a PITA. I'd reset the idle screw anyways. Get a service manual or look online for that carbs particular recomended setting. Probably around 1. 5 turns out. Any more than about two turns and once the engine is warmed up it won't idle. Don't worry about having it to lean. You can't burn an engine up by having the idle circuit to lean. It just won't start or run very good. Once you climb out of idle range the main jets takes over. The reason for an idle circuit is that the vaccuum developed by the engine isn't enough to pull fuel out of the main jets.



On a side note most of these EPA mandated carbs don't have adjustable needles. Depending on the application I'll put nylon shims under the needle seat to raise the needle a bit (. 040 is a good start sometimes).



I'm hoping since he put in the 330 kit he upgraded to a pumper carb. Pumper carbs that are setup correctly are sweet. If they aren't setup correctly they cause big headaches.



If I covered some things you already knew I'm sorry, just trying to cover my bases.

 

[AMink]

Wow, thanks CP. Pretty much you covered everything I don't know! I don't know if the carb is stock or not. I'll ask him. He bought from a guy who did all the work. It all makes sense, we'll just have to find time to look into it. I don't know if the stock carb on this one has the EPA crap on it, so I'll check and see if the needle is adjustable. Thanks again for the info.

 

[OKish]

yep, crappy carb, common problem. solved by putting a aftermarket unit on.