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jmccloud7

1998 CR250R Wont start

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i have a 1998 cr250r. i bought it in a bunch of pieces and had to put it together. i put it together and it was running fine. the other day the clutch went out. i replaced the clutch and ever since then i haven't been able to start it easily. when i does start the motor is flooded and won't idle. it runs good when i'm running the crap out of it but as soon as i let off the throttle it starts running sluggish. i can also kick it all day and it wont start. usually have to roll it off a hill and bump start it. the only mods are fmf gnarly pipe and fmf shorty silencer. i has had a recent rebuild with maybe 5 hours on the motor. as soon as i let off the throttle and it starts running crappy, i pin the throttle and it's sluggish then peps up like the spark plug is loading up and the motor is flooding. i have replaced the plug and it is getting good fire now. what could be wrong? i'm really frustrated because it is starting to warm up and i wanna go riding! :moon:

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Also, make sure the power valve is clean, check the reeds. Check the jetting in general and the air screw on the carb. Did you do the top end yourself when you put it back together, or did the previous owner say he did it?

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What octane gas do you use, what premix, and at what ratio? I'd start by cleaning and adjusting the carb. Sounds to me like your jets are plugged. What did the old plug look like? Was it black? You may know this trick already...but if not try it to get your (cold) bike started easier.

Turn on gas, choke on, tip the bike until fuel comes out of the carb overflow, give it two or three slow kicks with the kill switch pressed, let off the kill switch and then give it a kick like mean it.

Make sure you aren't turning the throttle everytime you kick it as this will flood it.

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i did the top end myself right after i put the bike together. i use 93 octane gas with amsoil sythetic mixed 32:1. the old plug looked a little black but it was still firing just as good as the new plug. I've never tried that method to get it started, I'll try it when i get home today. could it be all this cold weather? my '99 cr250r starts right up no matter what the weather and for the past 2 weeks it has been below 40 degrees

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Yeah my cr250 is a little tough to get going in the cold weather. In fact, my manual actually says that the larger two strokes are hard to cold start. I still think it sounds carb related... is it set up to the same/similiar settings as your 99?

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it is set to factory settings, whichever that is. i bought the manual for it and adjusted it to how it said adjust it. im fixin to try to start it how you all suggested but that still wouldnt explain the running bad when it starts.. ill try to clean the carb this weekend and ill get back with yall. i dont make sense it would be the carb if it was working fine one day then all of a sudden it wont run right

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it dont make sense it would be the carb if it was working fine one day then all of a sudden it wont run right

Well, it only takes a couple seconds for a piece of dirt to clog a jet... Even if it's not the carb, doesn't hurt to clean it.

Have you checked the compression?

I'm not sure how/if the clutch could cause this problem, maybe someone who knows a little more might know...?

Good luck man!

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Sounds like your float may be stuck open flooding your carb when your at low rpm. When you rev it up the float probably stays open most of the time to feed the carb at high rpm. have you tried tapping the bowl on the carb to see if the floats stuck? either way you need to take the carb apart to clean and reset the float level. may just need to bend the float or replace it.

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i have a 87 cr125 and was having trouble with the bike bogging down when loaded up. The bike kicked over easy and idled perfect but when i rapped on the throttle it would bog. Totaly cleaned carby jets ect.. and still no luck. I was starting to think it was spark related even though it started easy and idled great. well i took the tank off and checked the little plug from the coil and it was gunked up, wacked the file on it and cleaned it up and guess what?, running beautiful. Maybe check that.

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Sounds like your float may be stuck open flooding your carb when your at low rpm. When you rev it up the float probably stays open most of the time to feed the carb at high rpm. have you tried tapping the bowl on the carb to see if the floats stuck? either way you need to take the carb apart to clean and reset the float level. may just need to bend the float or replace it.

Yeah, it definetly sounds like the float boal is stuck. Try tapping on the bottom of your carb with a screw driver and see if that helps. You will have to clean it anyways tho. Also check the reeds.

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cleaned the carb today. it was pretty gunky but when i put it back together it was doing the same thing. i cleaned it throughly and its still messing up. i dont know if you all are familiar with this year carb but it has a little electric sylonoid on the carb that helps in the lower rpms. does anyone know whether or not it is suppossed to be closed or open while the bike isnt running? when i took it apart it was open.

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went outside to trouble shoot, pull the choke and it started 2nd kick, but still wasn't idling. i starting thinking about the thinks i had done since i had trail ridden it the last time. i had install the clutch and handle bars. then i remembered the billet throttle tube i put on. i adjust the throttle cable and now it is running fine. the carb was junked up though. thanks for all your help you guys. the warm weather is here and now i can ride :banghead:

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haha very funny. no know what im doin when it comes to rebuilds

Edited by jmccloud7

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