We may be talking about 2 different scenarios here. For the cold start problems, the drilling of the starter jet is the fix. I think the OP is talking about restarting the bike while the engine is still warm. A cold engine needs more fuel to start because of poor atomization in a cold motor. A warm engine needs less fuel to start because conditions for atomization are more optimum. David's description of cracking the throttle just a bit works because you're letting a bit more air into the combustion mix which usually aids starting on a bike/engine like the KLX when the engine is warm. This is kind of like what a hot start setup on some carbs do. Well, you say, this CV carb slide isn't attached to a cable for a direct pull, so that shouldn't work. But...with the engine spinning over and slightly cracking the throttle, the butterfly you are opening and the engine vacuum from the spinning motor will pick the slide up a bit, bringing more air into the mix and aiding starting on this warm engine.

Just slightly cracking open the throttle and holding it there is the best method. Twisting the throttle open and closed a couple of times may allow you to get lucky at the right moment for the amount of additional air to match with the fuel needed to start the warm engine. Remember, the stock carb has no accelerator pump, so you're not injecting fuel into the mix by twisting on the throttle. The warm/hot engine is usually needing a little more air at this point rather than more fuel.

 

+1

My bike (stock carb) almost always needs the slightest throttle opening to hot start, but then it starts great and very reliably.

 

Thanks for all the information, especially TNC. I agree that a new production bike should not be finicky to start. I'll definitely try opening the throttle slightly to see if that works.

Thanks!

 

I drilled my starter jet, and did the dyno jet thing. It starts good most times, but there are still times where it doesn't. I think there is still something not quite right with the ACR, as has also been discussed here in other threads - it's letting off too much compression or something. It should start better than it does.

 

Don't know if it matters that I'm on a KLX300 but with mine, I've done all the free mods, drilling and jetting the carb as described on this forum and I've never had a single start up problem hot or cold. Matter of fact, most every start I do happens on the first kick. The one thing consistent with both scenarios is I NEVER touch the throttle. I leave it completely closed and the bike fires right up. When I've touched the throttle is when I start having a stubborn starting KLX. Don't know if I happen to be the lucky one who got the easy starting KLX but it is just that.

 

Yeah, I know people who own or owned KLX300's, and they're not particularly hard to start for a kicker. The 250 and 300 are extremely close, but there are subtle little differences that get brought into the mix because the 250 has to meet stricter emissions to meet street legal criteria. I think this is the reason we see more of these niggling problems with starting the KLX250. I have said before and will continue to state that once you really get the KLX250 jetted properly, you lose all the starting problems...cold or hot. My KLX is as easy to start as my KLR600/650's have been over the years, and they were all stone reliable starters.

 

Yup.

If an engine has compression, spark at the right time, and a correct fuel mixture, it has to start and run. It has no other option. Since compression and spark delivery are more or less fixed, the only thing left (and the biggest variable) is fuel mixture. Most starting/running problems usually lie therein.

Ron

 

I have the same issue with mine. I have done NO mods to anything critical. If I touch the throttle AT ALL when i am trying to start my bike, it tends to not want to start easily. I usually will use the choke and dial it back as soon as she has started, and then she runs fine right away. I have no issues restarting the engine if I have to stop it and restart it in a short period of time ie just filled up with gas etc.

 

But that's the thing with the ACR - compression isn't fixed. I think there are at least some bikes that come with the ACR not set exactly right from the get go - as per some posts in the past here about dealer input & ACR remedy leading to a poor starting fix. The year is almost done for me here, but I think if this persists for me the enxt I will be looking further into it.