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Bike wont start.. only when its cold?

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The bike would start fine for the first few months I've had it, but now for some reason it just wont kick over when its cold. Not weather cold but just before the engine is warmed up. The only way to get it to fire is by spraying a little carb cleaner inside the carb, so it seems like its a gas problem? Since it needs that extra boost. Were running a hotter plug than what it came with too, thinking it would help. I'm thinking it must have something to do with the carburator but I have no idea what. I went through it and made sure all the jets were clear and everything seems just fine. If anyone has ANY idea what it could be then thats more than I know, so any help will be appreciated, thanks.

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Haha yes I do, I wish that was the problem! And even with the carb cleaner it still wont work without the choke

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What bike is it (year , brand/model , CC , 2 stroke/4stroke ?)

What is your elevation ?

What are the carb specs (ie: main jet , pilot , fuel/air screw turns out/in , needle clip position)?

If its a 4 stroke have you checked the intake valve lash ?

Kind of vague info you gave

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clean your air filter, i had this problem once where my bike would ony run on choke so i checked the air filter and it was completely caked with dirt and dust and it was completely clogged. man i felt dumb for really long, because before that i went through my whole barb and was kicking myself trying to figure out w.t.f was wrong with that thing... just a pointer.

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Oh yeah forgot to put all of that, my bad. Its a 1997-8 Kx125. So 2 stroke, and I dont know the specs for the carb. I'll check online real quick. I live in Oklahoma so elevation is about 1,000ft.

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clean your air filter, i had this problem once where my bike would ony run on choke so i checked the air filter and it was completely caked with dirt and dust and it was completely clogged. man i felt dumb for really long, because before that i went through my whole barb and was kicking myself trying to figure out w.t.f was wrong with that thing... just a pointer.

That could be making a difference for sure, I just cleaned it the other day when I cleaned the whole carb and havent ran the bike yet cause I'm waiting for chain/sprockets to come in. Hopefully that will help too though

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Oh yeah forgot to put all of that, my bad. Its a 1997-8 Kx125. So 2 stroke, and I dont know the specs for the carb. I'll check online real quick. I live in Oklahoma so elevation is about 1,000ft.

it's a 97 so i'm sure it doesn't have the stock jetting

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it's a 97 so i'm sure it doesn't have the stock jetting

I bet your right, it was being built for motocross so brand new top end but then the guy found out his girlfriend was having a kid, soo the bike had to go haha

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trolling a little here, but the brand new topend craigslist gig is out of the box.

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I bet your right, it was being built for motocross so brand new top end but then the guy found out his girlfriend was having a kid, soo the bike had to go haha

haha when i found out i was having a kid, i bought my KX ASAP cuz i knew i wouldnt be able to once he was born :bonk:

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sounds like it may need crank seals.

i dont want to sound like an ass, but what the heck would that have to do with something gone bad in the TOP end? if it will still run with some encouragement, than the bottom end is fine. if there was something amuck in the bottom, it wouldent even kick over.

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You may need to check and see if the choke is really working or the pilot is to lean with it getting cold, not enough fuel at the start up. Float working correctly? Excessive smoke after running awhile may be an indication of right side crank seal gone bad as someone stated earlier. Could be top end is weak to. :bonk:

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What really confuses me is how good is runs once it gets started. Like starting is the only problem it has. & I don't know where to start with the carb honestly, never really messed with the settings on it, I'm thinking that's probably what the problem is but have no idea how to tweak it?

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Are you talking about the spark plug gapping?

No, the gap between the nub on the flywheel and the pickup. Mine was set at about.93 when it was supposed to be about :033 or something close to that

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