Thanks Dan, I should have worded my response better. No offense 09klx, I should have said, I would think that someone who has posted 92 times would have seen the cold start issues on this forum. I know I have. Sorry if I offended you. Maybe I read more than I post. The old saying of you learn more listening that talking has proven true to me more times than not. There are numerous people on here who have done no mods and some that have done everything imaginable to their bike. Making mods to your bike is not a prerequisite to posting. Sorry if I came over as a D%*@. Maybe, as Dan said you might turn out the fuel/ air screw and it might help. Just search this forum for "cold start" and there will be plenty of reading for you. Over 200 results. Good luck!

 

hoping that i don't get clobbered here ( :-) ), but can someone tell my what the Kouba screw does different than the screw that is currently on the '09 (if i am looking at the right place, its like my bike already has something similar to a Kouba (but it doesn't have the "T" handle, more of like a fat threaded screws.

 

No more clobbering!! That was my fault I guess. I don't know what screw you are talking about. Are you talking about the idle adjustment on the right hand side of the carb? The kouba screw is a replacement for the air/fuel or (pilot jet) screw located under a factory cap (that is removable), on the bottom of the carb. It makes it easier to adjust instead of having to pull the carb. Try this thread.
https://www.kawasakiforums.com/forum...lx250s+exhaust

 

Dan, on my jetting, you may not remember how I was surprised that my jetting with the Muzzy exhaust and opened airbox continued to be the correct jetting even after installing the 300 cylinder. I installed a Kouba fuel screw during the 300 installation to really experiment with the pilot jet size. I installed a 38 pilot but had to go back to the OEM 35 size. The current jetting of 128 main, 3rd notch from the top on the DJ needle, and 1.25 turns on the fuel screw worked out the same for the uncorked 250 as it did for the 300. This was a surprise to me, but I'm sure the jetting is dead on the money. I think the motor develops slightly more vacuum in 300 form which affects this. It carbureted so cleanly on the Moab trip all the way from 3500 feet to even 10,000 feet, and I was really impressed with its clean running from idle to wide open. Fuel mileage under hard riding was excellent IMO.

Dan, on the fuel screw adjustment vs. the starter jet size, I think richening up the lower end of the fuel delivery curve helps. However, nothing affects cold startup performance like the starter jet. My opinion on overall jetting has usually been to run as lean as possible without verging on detonation or stumbling. Clean, crisp fuel delivery keeps the carbon buildup down, increases fuel mileage, and causes less issue when altitude climbs. I'm super happy with the jetting on this bike. Power is strong, mileage is excellent, and an absolutely linear feel in the powerband exists throughout the range.

 

The Kouba fuel screw allows you to more easily adjust the fuel screw setting while the bike is hot and running...which is when you should really be adjusting the fuel screw. On your new bike, you generally can't see the actual fuel screw, as there's a plug covering the access hole. It's located right at the front of the carb on the bottom, very close to the rubber intake manifold. It takes a very short bladed screwdriver to access the stock fuel screw when the plug is removed. Trying to do it on a hot and running engine kinda sucks.

 

thanks for the replies. I haven't really taken a close look at the carb on this bike (but will when the DJ kit arrives, hopefully this week). After reading the above link from scallen, I took a look and realized what I thought was the same screw is probably just the idle adjustment:

 

jxg, you're right. But in your pic there, look directly to the right of the knurled idle **** and notice the shiny head of the fuel bowl screw. Just below that screw head in the darkness, you can see the light shining on the edge of the housing shrouding the fuel screw. Look and you'll see a plug glued into that recessed hole.

 

If it is a needle jet, it has a part # of 16017-1439 on this diagram. http://klx250s.suncup.net/Misc%20Doc...LX250S_IPB.pdf Page 14

Borrowed a small set of drill bits, might try it tomorrow. I think this is what the Yamaha dealer suggested for my son's hard-starting TTR-125 last year, but I didn't understand what he was talking about then.

 

kawi p/n 019-511 description N424-25-038 38 pilot jet
kawi p/n 019-512 description N424-25-040 40 pilot jet

Without permanently drilling out any orifice in the cvk34 carb, using a bigger pilot jet and the kouba fuel mixture screw the hard starting problem was taken care of 0-100' asl.

Mods included 2 bros slip on exhaust, weld bead ground out inside fmf powerbomb header flange, uni filter, 132 dj main jet, 1.5-2.0 turns out kouba fuel screw, no airbox lid, drilled slide, 40 pilot jet, 3rd clip from top dj needle (dj kit 2206), case breather drilled to 3/8", 91 octane mobil/shell gas

ymmv

 

Needle jet is under the main jet. It's what the needle sits in and guides it as it rises.