+1 on the ground mod. In the surge post. Worked great for me

 

Could you explain what a "dyno jet" kit is, and where to find it? I do know this hesitation problem cannot be both a carb problem and an electrical problem. There may be issues with both systems on the bike, but they would be causing slightly different symptoms. It seems some people have solved the problem by new jetting, others with the grounding alteration. I haven't had time to try the new grounding, but I will asap.

 

Hi JDM, The dynojet is a kit (available at MC stores or online retailers for approximately 60 bucks) that contains a box of a few different "jets" and a needle or two in it. These jets are small screw in orifices that meter the fuel through the carburetor that the engine receives. In conjunction with the 'needle' (tapered rod in the center of the carb) the amount of fuel that can flow to the engine at DIFFERENT throttle positions can be altered to suit ones preference, altitude, atmospheric conditions, to create the perfect 'burn' inside the combustion chamber.

The installation of the proper jets and resulting fine tuning could take anywhere from several minutes to several hours depending on how many times you have R&R the carburetor/float bowl before.

Do the grounding wire modification FIRST. It only took me a half hour to do. The toughest part was finding the proper tool (dental pick for me) to remove the spade connector w/ black and yellow wire (that you solder the new 3" ground wire to) from the white connector block.

Easy to do compared to new jet kit and may solve your problem. If not, it wont hurt in the future.

 

+1 on this ^^

Also make sure you are grounding the actual R/R and not the just the harness that the Reg/Rec leads into if you don't include the original ground.

 

thanks to everyone. it's a rainy day, i'll be in the shop soldering on the new ground, and I'll order the new jets. But, one more question. Does a re-jetting demand a new exhaust? Mine is stock and I see an awful lot of posts saying that if you replace one you should replace the other. I need a quiet exhaust.

 

I am not an expert on this JDM, BUT, I believe you CAN re-jet with the stock exhaust (very lean jetting from factory), yet you CANNOT (or should not) add an aftermarket exhaust without re-jetting.

Side note: with the stock exhaust on, after the ground wire mod, you might remove the factory installed plug that covers the air:fuel metering screw (under the bottom of the carb/ in the center/ between the slide and intake manifold) and adjust it outwards a bit and see if that makes it run a bit better. Others will be along shortly with some more experience/wisdom/better advice

 

I bought the Dynojet kit and installed it in my otherwise stock bike. The kit comes with 4 main jets, I used the smallest as that is what the instructions say for a stock pipe and air filter.

The difference was night and day, I even had the bike in previously under warranty, they had drilled out the air screw and adjusted it but the bike still hesitated badly.

The kit comes with a softer diaphram spring, these carbs are the CV type, the throttle opens a butterfly valve, but vaccum opens the throttle slide. The softer spring allows the slide to open faster and sooner. If you twist the throttle and the slide isn't lifting, it's not going to run very well.

I don't want to put a pipe on mine either. The kit also improved the cold starting. What I found is if it doesn't fire right away, crank it for about 15 seconds, let it sit for a bit, then hit the starter and it will fire.

The dynojet kit is about $50, jets are probably a few dollars each. However with the kit you get the correct pieces, instructions and the washers and spring for the slide. The $50 was well worth it to me,
I was ready to sell the bike. Shame on Kawasaki for selling a bike with such a bad carb setup. My wife has a stock CRF230L, it starts and runs very nicely.

 

yyz, any chance your bike could have sit for a while and had a small amount of gum in the stock jet, then once you added a new jet you fixed the problem and now have a bike that runs how the kawasaki folks ment for it to. The reason I say this is these bikes are not all that lean in stock form if the were they wouldn't run well new and they ran fine new. I've seen the afr on more than 1 stock bike now and they are jetted fine for they way they are set up. They are just stopped up with limited air in and out, That is why people who have done a stage two time mod with jetting say it is a different bike once some of this restriction is removed.

 

My '09 SF has recently developed a high-speed misfire at 6000 rpm and over. It began suddenly after refuelling at a no-name rural gas station. The symptoms and circumstances seem consistent with dirty fuel which has clogged the main jet but I have not had time to pull the carb yet. I did however try the grounding modification mentioned here as an easy part of the elimination process...it did not fix the problem.

 

Do you run an in-line fuel filter, in addition to or instead of the little stock sock-screen?