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Weird problem to have? 1999 RM250


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I Put in a newspark plug and cleaned the carb thoroughly before i ran it the other day and it was really tough getting started.. I noticed the spark plug wet & black so i replaced it. It took about 10 min of kicking but it finally turned over with the new plug.

1. Once in gear it doesn't want to stop. Ive spent more time on an XR200 than anything else so if this is normal behavior for 2 strokes then that would be nice!? but if I let the clutch all the way out slowly, w/o giving it gas, the RM250 is pushing 4-5 times faster than the xr200 would. I was hoping these 2 issues would go hand in hand.

2. After riding for a couple hours we took a break. After it sat for a few hours I went out to ride again and it wouldnt start?? smelled gas in the air and the spark plug was wet & black again. Also If i accelerate slowly 1st-3rd gear, it was fine. But when i would give it gas it would kind of hesitate, sputter a little bit, then slowly start climbing RPMS.

HELP PLEASE!!

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did you change or adjust anything while you were in the carb? Possibly bent the tab on the float that is attached to the needle and seat? This would allow fuel to flow through the carb even at rest.

sounds rich to me (obviously 🙂)

I would pull the carb again and check to make sure everything is set to stock, jet sizes,air screw setting, needle clip position. Also, check to make sure you have a tiny little bit of free play in your throttle as it almost sounds like your throttle is partially engaged all the time.

This is an article I came across yesterday. It is for scooters, but all of the theory applies to any two stroke. I used it when trying to get my KX to idle properly. Give it a read. I think it might give you some ideas.

http://scootrs.com/tech.cfm?tip=tunecarb

-Wes

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Yea that makes alot of sense. What is the trick to getting to the needle clip? When I pull the slide out im having trouble figuring out how to get to it. I know this is probably a newb-ish question. But it is different from the XR.

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not exactly sure on the RM. I do know you do need to unscrew the cap on the carb and slide the throttle slide assy out of the carb body. Then pull up on the spring (toward the cap) to get a look at the way the needle is held into the slide.

On older mikuni carbs, you just have to lift a thin sheet metal plate out from under the spring and then the needle comes right out. On my 91 KX (kehin carb) you pull the spring back and unscrew a little 6mm cap that secures the throttle cable and needle in place. It should be pretty intuitive once you look at it.

The needle just rests in there, nothing complicated. Changing the clip position just supports it at a different height within the slide.

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