Failing miserably starting my '02 EXC250, need help.

[ShibbyZ]

I am a WR450F owner/ rider. I purchased a second hand bike for my son (and myself). I got an 02 EXC250 from a fella in Texas that moved here to FL. I'm new to a 2-stroke. I have been researching the threads for info.

I bought it in July. Rode it once for about four hours. Ran 40:1 pump gas. It was smoky, but I ride low rpm in the woods. Two weeks later I could not restart it. Compression test led me to replace the piston and rings (90 psi). I have diassembled and cleaned the carb. Blew out passages with compressed air, etc. Physically, all looks good. No cracks in the intake or obvious leaks. TVC is free moving. I have fuel flow from the tank.

I have yet to even hear a backfire. New plug, gas is about two months old now. The compression is good, I have spark (just checked it again a moment ago). I have read and read trying to figure out what I may have missed with no success. I have not measured the primary/ secondary voltages as I have blue spark. I cut the end of the plug wire at the beginning for a fresh connection and use di-electric grease. I have looked at the reeds and don't see anyting obvious.

My jetting is how I bought it:

175 main, 45 pilot, NOZG needle on 2nd clip, 1.5 turns on AS.

I'm in FL and realize the jetting is off but I'm not building the shuttle.

As I said before, I rode it. Stopped and started it several times. Something has slipped by and has me stumped. Any advice would be greatly appreciated. This bike was 4 hours of fun and I'm really missing out on 'woods time'.

[ds66]

i know you have blown air through the carby, but did you use 'carby cleaner'? this allows you to put the can nozel right up to the each jet (that you took out of the carby) and blow the cleaner clear as you will see the liquid come out the other side.

[ShibbyZ]

No I haven't used any carb cleaner. My next opportunity to break down the carb again will be this weekend. I'll try it.

I just gave it about six kicks, choke on for two, and the remainder at 1/4 throttle. It's got a good hard kick since the piston swap. I pulled the plug wasn't wet. How 'wet' should it appear with 6 kicks and no start? Prior to the kick, I tipped it on it's side until gas flowed from a vent.

[Footy]

Well I always say this when a bike is difficult to start, "clean the pilot jet". If it is plugged it may not start and if it does it won't run worth a crap. My next thought is the kill switch. It could be bad or rusted/corroded. Also make sure your carb vent lines are not plugged with mud.

[Hondaman24]

My 02 250EXC starts fist to second kick every time. Go 50:1 on premium fuel though. Sounds like a clogged pilot or breather tube.

[sbest]

Ditto the 50:1 recommendation, works for me. Less fouling.

Hmmm, float level not too high?

If a few kicks with choke on don't start it assume it is flooded, close the choke and kick it over with full throttle. Should start in less than 6 kicks.

Sometimes if the fuel is left on (or if the petcock leaks) it will fill the base of the engine with gas, which evaporates, and leaves oil. Hard to get clear. New plug is always a good start.

[Layton]

No I haven't used any carb cleaner. My next opportunity to break down the carb again will be this weekend. I'll try it.

I just gave it about six kicks, choke on for two, and the remainder at 1/4 throttle. It's got a good hard kick since the piston swap. I pulled the plug wasn't wet. How 'wet' should it appear with 6 kicks and no start? Prior to the kick, I tipped it on it's side until gas flowed from a vent.

You obviously are not getting fuel to the engine. Here is how you start the bike.

First turn the fuel on.

Second lean the bike all the way over on it's left side until fuel runs out of the overflow hose.

Next pull the choke on and kick the bike "without" giving it any throttle.

It should start after several kicks.

I don't think just kicking it twice like you said you did with the choke on is enough to get the bike started. Then giving it 1/4 throttle just compounded the problem.

If it doesn't start after doing what I wrote, then pull the plug and see if it's wet or not. It should be for sure.

Let us know what happens.

[davecampbell]

try starting it with the pipe off. You may have a plugged pipe or silencer. I had a kdx that a piece of the silencer broke internally and caused blockage. I know it is a long shot but you have something wierd going on there. I personally use a shot of starting fluid to test if I'm fighting fuel issues. I shut off the fuel and drain the carb and then give it a shot of ether.

[ShibbyZ]

Thanks everyone for the info. I have the carb off and will D&A tomorrow for a more thorough inpection. I plan to remove the reed valve again. I have a powerful penlight to poke in and look for light leaks. I did confirm the kill switch is not faulty. I'm most certain it's my technique as I can light up my four stroke at any time. Full throttle scares me as to easily flooding the thumper. Just new to this 2T and frustrated. I will use your advice and let you know. Thanks again. I have to admit the grin this KTM has given me only riding it once. Truly agile in the woods. My 450 weighs on me in anything technical, a big workout. Got a 21 year that loves it. My 16 year old patiently awaits.

[ShibbyZ]

I apologize. I left one out. The pipe is clear and the silencer has a fresh packing. This was done before I rode it because it was so loud. Thanks.

[sbest]

Full throttle scares me as to easily flooding the thumper.

Full throttle starting will not flood the engine on a 2 stroke. With the slide wide open there is no air flow through the idle passages and not enough air movement for the main jet, it goes lean. This is the standard technique for solving flooding on any engine.

This even works for fuel injected engines but only because they have been programmed this way. On 4 strokes you have to be careful because they have an acceleration pump that will pump extra fuel every time you move the throttle. The hotstart valve acts to lean it out without squirting fuel in.

I have driven 2 and 4 strokes for over 35 years now, and find the KTMs some of the easiest to start, certainly easier than the new 450 4 stroke kick starters after a tipover. If everything is right it should start with no more than 3 kicks from cold or a tip over and 1 when hot, otherwise your pilot jetting or float level is off. All those hoses hanging off your carb are there as drain tubes in case of tipover. If the float level is too high, even they are not enough and excess fuel will splash down the carb throat.

Your jets sound fine, you have spark, you have compression. Poor reeds or poor crank seals will make it start bad and have poor idle. The flywheel side seal can be checked with a shot of carb cleaner (will change idle). A bad drive side seal will make constant smoke that smells different than 2 stroke oil.

Plugs and oil are critical on a 2 stroke. If ever in doubt,throw a new plug in the engine and always carry one on you. I ditto the 50:1 and premium fuel recommendation, these bikes are built for premium octane fuel and 50:1 keeps it from fouling the plug at low speeds. Also recommend premium oil, which resists fouling as well as seals the piston and lubes better.

No start after a tipover is a sure sign of too high a float level. Check that, check the pilot is clear. The plug should be dry but smell of gas if the choke was on. If it is greasy wet, replace it at least for starting. If it won't start, a sniff of the pipe will tell you if you are getting fuel or not (lean or rich if spark is good).

Expect more out of your KTM, it is there!

[ShibbyZ]

Thanks everyone! You're the greatest! My reed petals looked good. D&A the carb and really didn't see any obstruction. Vents are clear. Looked through my pilot with a loupe. Squirted through any passage I could access.

Reassembled it and TWO KICKS! Adjusted AS and idle and let it heat up. Placed my carpet fan in front and was consumed by the sounds of fun to come. If there was any blockage, I took your advice anyway. I feel most certain it was my technique. It was too easy. I'm shakin' like a chihuaha that's gotta pee! A few more starts and I'll feel much better.

Now the hard part. Do I ride tomorrow or stick with my plans to take the wife to the 27th annual Gold Cup MX? It's Biff Burger and hotrods afterwards.

Now I can tackle the fork seals and heim joint (after I start it again).

I've always read these forums since I got my '01 YZ250F. Moved on to the 450. And now the KTM. I've never really had much input, only absorbing the info.

Again, you all are the best. I'll try and be more involved. I do need to learn how to post photos so you can view my rides.

[ShibbyZ]

Third hot start. First kick w/ no throttle. It's intermission time! A cold beer and ponder the events to take place the remainder of the weekend.

[sbest]

Third hot start. First kick w/ no throttle. It's intermission time! A cold beer and ponder the events to take place the remainder of the weekend.

Wahooo!

Don't cha luv it when a plan comes together!

[KcDavis]

Glad to hear you got it all squared away!

[ds66]

congrats, i am sure it feels good to be running again:)