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hard starting - cold engine

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'04 YZ250F...all stock jetting/pipe, ambient temp ~60 deg. F., when the engine is cold the bike will 8 times out of 10 NOT start with the choke on (no throttle twisting of course). After kicking ~10 times I'll turn the choke off and kick it over with the hot-start pulled in and it'll fire and then die (because it's cold, I presume). Is this an indication that the pilot circuit might be too rich? Or maybe I just don't know how to kick it over... I understand that it'll flood if it doesn't start too soon when the choke is on...frustrating.

When the engine is warm it'll start with the hot-start lever on the first or second kick.

Plug was a little bit fouled when I checked last, so I replaced it.

After every ride I change the oil and then turn off the gas and run it until it dies (to empty the carb/bowl). Could this be aiding the hard starting? Wouldn't think so...

I'm tempted to try adjusting the pilot circuit (using the fuel screw) but not sure if there's something obvious I'm missing.

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How many hours on the bike? Are the valve clearances OK? That's the first thing I think of when I hear "hard to start."

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Thanks; there are just over 10 hours on the motor. I checked the valves for the first time this past weekend and they're still in spec.

While doing the valves I changed the oil (yamalube 20w50), oil filter (OEM), replaced the coolant with Engine Ice, and cleaned and re-oiled the UNI air filter.

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Completely cold. give two or three twists of the throttle first, should start right up. I don't have a choke, mine broke off, so I give 6 twists of the throttle and it always starts first kick. And yes, it does get down to 60 degrees over here. :cry:

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After every ride I change the oil and then turn off the gas and run it until it dies (to empty the carb/bowl). Could this be aiding the hard starting? Wouldn't think so...

I can see doing this if the bike sits for long periods between rides (a month or so), but I don't think it's necessary otherwise. Try just shutting off the gas when you shut the bike off, and don't run it dry. See if that makes it easier to start cold.

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giving it a little bit of gas when starting is ok. Everyone who says that is wrong. I mean the hot start is just giving it a little bit of gas afterall. Why do you think it pops when you pull the hot start. Just give it a little, it should pop right off, mine does. :cry:

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actually the hot start doesnt give it more fuel it gives it more air. check valve clearances aain and when you turn the bike off kick it over to top dead centre as this seals off the cumbustions chamber from atmospheric gaseswhich can caus carbon deposits on the faces of your valves whih will make it hard to start hot or cold.

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'04 YZ250F...all stock jetting/pipe, ambient temp ~60 deg. F., when the engine is cold the bike will 8 times out of 10 NOT start with the choke on (no throttle twisting of course)[/].

Thats your problem. When the bike is first started pull the choke out, ready the kick starter, blip the throttle 3 times and kick it. You gotta prime a cold engine.

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