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I dunno anymore!

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04 just aint starting!! I threw a new plug at it and cleaned the carb and still no dice. just had the valves shimmed and got about 6 hours on in untilit crapped out. I can kick it over with my hand. Does that mean that i need to pull the head off and check the valve seats and valves? just that if you can kick it over with your hand there's prolly no compression at all.

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yep i just checked my valves again and i have no clearance on my right side intake so i think i burned it out :thumbsup: i just drained the oil and imma gunna start tearing the head off HORAY!

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k so the valves are good and everything looks good. Just looks like the shim that was in there somehow is too big or something. thats weird

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would having too big of a shim on my intake valve prevent it from starting?

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My 04 has always been a bear to start as well. I've probably spent more times shimming the valves than I have riding it. The bike has 90 hours on it, complete valve job with stainless valves, new everything, 3 pistons. It's always been a bear to start. Shim the valves until they are in spec, then don't flood it. When mine won't start, I turn off the gas, no choke, open the throttle up all the way and HOLD IT THERE. Don't be opening an closing the throttle because the accellerator pump squirts gas every time you crack the throttle. Then kick until it starts popping, then turn on the gas, no choke. Close the throttle and start it, then pull the choke once it starts to keep it running, then get moving before it overheats.

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yeah now the trick is to actually get it started tho. it's like the bike is completely dead. there is spark and there is gas, its just that one valve that had no clearance. so i thought that the valve was toast and pulled my head off and everything is A ok. the head had ALOT of carbon buildup on it though so im going to take it in on monday and have the valves re-lapped and re shim everything to spec. just wondering if having no clearance in that one intake valve would cause it to not start? not even really want to start.

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Yes, if the valve had zero clearance and was open all the time with very low compression, it may not start and if it started, it would run poorly with backfiring and no power. My valves were zero'd out from time to time but I could get it started, but the thing would wear me out kicking it. Push starting is tough as it usually locks up the back tire and skids. Mine new, used rebuilt, whenever, is always hard to start. Seems you just can't get a good kick on it. But once it starts, it still runs pretty good. Great power from the 04. Pulls most other 250fs in a drag race. Good power.

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thats exactly what was hapening. I got it started once and i couldnt get it to idle, that was after about 50 freakin kicks!. its too bad that i had to get curious and rip the head off, otherwise i could have just re shimmed it and been riding today. from now on im going to do all my own shimming, becasue the dealer did it this time, it'll be the last becasue 6 hours of riding isnt worth taking it in for, at 150 bux a pop. There was ALOT of carbon buildup on the head as well, so im sure that might make it hard to shim. once i get it all cleaned and relapped im sure that the shimming will last a bit longer without all the carbon on the seats, just now i cant ride for another week.

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If you plan to keep the bike, plan on doing frequent shimming and frequent oil changes. If you have alot of carbon buildup, race gas burns cleaner than pump gas, much less ash and carbon buildup. A shim kit with lots of shims is money well spent, plus a good micrometer and feeler guages. Stainless valves and getting harder valve seats installed, good idea. New valve springs, buckets, retainers, washers, guides, cams, cam chain, pretty much the entire valve train, good idea. The kx250f runs well, but it is maintenance heavy on the valve train. You definitely do NOT want to break the head off a valve, so keep on eye on them. I would recommend stainless steel valves. You'll spend more now or more later. Just the nature of this 4 stroke. It runs very well, but is maintenance heavy to keep it in the sweet spot.

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yeah if they are moving that fast after i got it shimmed its probably a good idea to do the valves and springs, seats and guides. its probably a sure sign that they are on their way out im sure. i best do that while i have the head off. any good recomendations on where and what kind of kit to get?

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