Cheap gas. I had the same experience with the gas from the KLX650. Match to it - no light.

 

So at the risk of repeating myself, there is something about our CVK34's ( or the way the CVK is plumbed in our KLX's) that destroys fuel volatility in a very short order. Draining the bowl a little or, as one member has already verified, a good shake to force a little bit of new fuel past the needle/seat into the bowl, is required.

 

The only question I have about fuel volatility being the issue here...or at least the main issue...is why every single KLX250 with a CVK34 doesn't do this after the 10-day/2-week period?...just as every single KLX250 with a CVK34 with the stock starter jet doesn't absolutely need to be drilled...or every KLX250 doesn't need to be shaken or leaned over before starting. Interesting inconsistency.

 

I will be happy for you to ask and answer your questions..

I only know of the problem and how to easily remedy it - which is good'nuf for me ( on this issue)..

 

From a non-nerd, I would say it may just depend on the gasoline blend, up here it changes with the season, with winter and summer blends. My 250 can do two weeks or so, 650 never could. Could be a bit hotter ignition on the 250 or something.

 

The problem with the question and the answers is that neither are uniform. This long, ongoing issue of some carbed KLX250's having cold start issues is probably not the exact same problem for every bike. The vigorous shaking of the bike, draining the float bowl, making sure the fuel level is at maximum, or drilling the starter jet all have yielded success in many different applications. The one solution I would refuse to live with on any bike is the draining of the float bowl. Who wants to own a bike that you have to drain the float bowl every time you end a ride, or start a ride, to insure the highest fuel quality for a cold start? Of all the solutions mentioned, insuring maximum fuel level and drilling the starter jet is a one-and-done procedure. And while this doesn't allow you to let the bike sit for weeks or months without screwing up the pilot circuit, it does insure a maximum amount of fuel to be delivered at cold start up.

I would like to blame the CVK34 carb itself for some flaw in its design or at least in the state it's delivered on the KLX. And while I think the starter jet as delivered is on the small side, the overall design of the carb is probably not the main issue as it's basically an exact replica of the CVK40 that's been on the KLR600/650's for decades and works quite well. There probably is a weakness in how the CVK34 works on the KLX that may be related to a low engine vacuum issue that could be tied to the KACR, cam timing, etc., etc. That potential mystery could only be solved by some kind of intensive lab study involving lengthy dyno testing, monitoring, parts swapping, etc. It's a KLX, not an F1 car, who wants to invest that time and money. When you get right down to it, the real solution is a 34mm or 36mm pumper carb or FI...FI being the ultimate fix as time went on. There's a reason Bill Blue went with his modified 34mm pumper carb to be a much better solution that modding the OEM carb. The OEM carb just has some inherent limitations on a modded engine regardless of its frequent cold start issues. And while the two pumper carb options don't guarantee some kind of highly noticeable power increase, what they bring to throttle response and smooth fueling, along with guaranteed cold starting quality, is well worth it.

 

What has become obvious over the years is that you never advise a member to remove and dismantle his/her CVK34 (and especially take a drill bit to its' innards..) unless doing so is absolutely necessary.. This is my "golden rule"..

If a peep will not shake his bike, or drain a little fuel, before starting, after days of sitting, then they might consider facing the risks of a carb session. Main risk is weeks of down time while they research and study to learn what the hell they f%@k'd up during the carb session.

 

Only a select few are allowed to do that, right?

 

Right !
And I am the only person that chooses who gets to tear down their carb, and who doesn't..
If fact, no one can do anything to their KLX without first getting my blessing.
And Mark, I'm gonna need a 24hr notice before I can let you ride yours..

Thank you for your cooperation..

 

Absolutely shake it side to side while on the bike and holding the starter with choke on, no throttle. It works! Try it and report back.