2000 KDX200 -- Issues with kick starting when cold

[Xiahoux]

I have a 2000 KDX200 which is very hard to start when cold. I can kick it 30-40 times, choke on and off, every combination and it will eventually crank. But, here is the trick...I can bump start it with zero effort and then the bike purrs. After the initial bump start and 30 seconds of warm-up you can kick start with no issues; first time, every time.

I have read lots of articles online that talk about a leak in the magneto at the crank seal and how this could create the hard to start situation. I pulled the flywheel yesterday and checked it out. There is the slightest bit of dried oil below the seal but nothing significant. I am guessing that that accumulation happened over the 9 years of the bike and is nothing major.

Carb is freshly cleaned and floats are adjusted properly. I have tried the "lean the bike over to flood the bowls" trick as well. No action that I have found will make the bike easy to kick when cold. Any ideas?

 

[bonecrush]

i have a 94 rm250 same problem ive found that if i kick it 3 times choke on and no throttle then turn choke off and gas it when i kick it fires in 2-3 more kicks

 

[truckster225]

I agree with bonecrush. What that could mean is that you are flooding it at the initial start-up.

When its warm out, do you have the same problem? If not then chances are you are loosing compression. When everything is cold, it all shrinks. That will make the gaps between the rings and cylinder a lot wider, making it near impossible to start up until you've had enough combustion to warm the engine enough to lessen all the gaps.

I recommend you do a compression test before you start it. If its low, it probably means its time for new rings. Small job, dont sweat it.

 

[dirt bike dave]

FWIW, worn reeds can make a cold two stroke nearly impossible to kick start.

Inspect your reeds, and replace if any sign of warping, cracking or chipping.

 

[Xiahoux]

Brand new reed cage installed about two weeks ago with no change in behavior.

 

[dirt bike dave]

Are you kicking it over in neutral or in gear?

What is your jetting?

Clean, not over-oiled air filter and silencer packing good?

Are you accidently twisting the throttle as you kick? If so, put your hand on the master cylinder just to be sure you don't crack the throttle.

Here is my starting drill that works well for most all two strokes.

Bike in nuetral.
Turn the fuel on.
Lay the bike over for 10 or so seconds - you want lots of fuel pouring out the overflow tubes. If you pick the bike up as soon as the first drop comes out the tubes, it might not be enough.
Pick the bike up, turn the choke on.
Kick over SLOWLY 2 or 3 times to prime the cylinder (don't open the throttle)
Return piston to top dead center (you can feel this with the kicker - the compression will increase gradually, than rapidly decrease. Stop the piston just as the compression eases, and you are at TDC. Being at TDC allows maximum piston speed on the next compression stroke)
Kick as hard as you can without opening the throttle (FWIW, some bikes like a tiny bit of throttle, like 1/16 open, but my KDX's always liked no throttle best).
If no luck, return to TDC and try again.

Just trying to rule out technique issues before you rip your bike apart...

 

[Patman]

How old is the top end?

 

[truckster225]

Save yourself a whole lot of work and just do a compression test. Im willing to bet its time for a new top end. Its pretty much routine maintenance, especially if you ride hard and often.

 

[lycos112]

Did a compression check just now. Spec is 90-151 PSI and I am at 149 PSI. I put a spark detector inline just for giggles and kicked it twice just to say I had done that. The friggin' bike fires right up.

When I reconnected the gas tank it took a lot of gas to fill the bowl. It now seems like, with good compression, that when it started so easily there was very little fuel in the bowl, no throttle and no choke. Maybe it is my starting methodology that is causing the trouble. Is it that easy to flood a two-stroke? I am going to test now.

 

[lycos112]

Same thing after reassembly...no throttle, no choke and it fires up after two kicks. I am not completely convinced that there is not another carb adjustment that I need or something like that but I will kick it tomorrow when it is cold and see what happens.

I think that I was flooding the bike. I had seen repeatedly to open the throttle and hold while kicking. I suppose that I have just been flooding the whole time due to what I have read. Opinions?

Any other tips are greatly appreciated. I will post follow up results tomorrow evening or Wednesday to assist others who may hit this same issue. Thanks to everyone for the help and suggestions as well!

BP

 

[lycos112]

Oh yeah, to answer the questions:

Same behavior in 90 degreee weather or 40 degree weather. Kicking in neutral, stock jetting, brand new air filter oiled just right. I am assuming that the top end is nine years old (factory). Runs like a dream once it is warm.

 

[truckster225]

My old carb was SOO touchy. It would flood so easy. I found out that my float was not operating properly. Im saying thats your issue, but its a pretty simple thing to rule out. Im glad to hear it wasnt your compression! At least with a carb issue, it doesn't take much to pull, try something, and put it back in!

Nice job.

 

[julien_d]

It could indeed be float level. Maybe try dropping it a bit and see if that helps. If my piston and rings were 9 years old I'd be replacing them ASAP if just for piece of mind, regardless of what the compression test said. They do have a limited lifespan after all. It's cheaper to do it as preventative maintenance than to do a complete rebuild due to a shattered piston skirt.

 

[porterdog]

You didn't answer the jetting question, and here's another: What's your fuel screw setting?

Oh, one more- have you tried increasing your idle speed? That can make an *enormous* difference.

My KDX starts regardless of ambient conditions in 3 kicks max.

 

[reepicheep]

My old KLR-250 (CV carb) was very fussy about both idle and fuel air screw. There wasn't a single setting that was right for both cold starts and really warmed up, so you had to continually fuss with the idle depending on ambient temps and what you were doing. And you had a choice of "easy start but bogs when you whack the throttle" or "harder starts but runs well when finally warmed up". In short, every setting seemed interdependent on every other setting, so it was a bit of a chore to align all the planets.

I prepared my self for the same battle with my rebuilt KDX-200 H2, and found that I couldn't hardly screw it up. Throttle stop screw could be in a lot of different places, and it didn't matter much, though there was a right idle. But aside from idling at the wrong RPM, the throttle stop position had no other effect. The fuel air mixture screw could be half a turn out through two and a half turns out, and the bike seemed to run fine as well. So I put it to the lean end of the factory recommended range, 1 and a quarter turns out.

Now I've only run this bike on hot days, so maybe when its 40 degrees out I'll be singing a different tune... but for now I'd say that what you are describing is "something broken" not "something that needs to be tuned". So I guess I'm with everyone else saying check the plug, spark, reeds, quality of gas, compression, float level, clean carb, etc.

 

[glad2ride]

It sounds like you were flooding it by holding the throttle open.

If you can kickstart it cold with no throttle and no choke, then you may want to check your pilot jet to be sure it is the correct size (after warmed up).