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07 yz 250 rebuild

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I just rebuit my 07 yz 250 because it had over 80 hours on it. It was running great before the rebuild. I put oem parts back in. Piston, rings, clips, bearing, and pin. The only thing out of the ordinary with this rebuild was that I had a pencil lead sized nick out of the side of the right side sub exhaust port, Im talking a very small nick. I took my dremel tool and chamfered the edge just enough to take the nick out. Eveything looked great, put the bike back together, did my normal break in, and now there is a hesitation/bog at 1/2 to 3/4 throttle. I did not change anything else but the top end, so I was wondering if that small little spot I chamfered is causing this problem. Any ideas????????

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thanks for the ideas. I did try changing the needle and it did not help. So i tore the top end back down tonight to check eveything out and it all looks great. Will be going back together tomorrow. If it still runs the way it was I will be going through the carb. Any more ideas will be appreciated. I still wonder if the little bit I had to take off the sub exhaust port is causing this.

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Check your plug for the jetting if the needle didn't help. If it is hesitation then you're rich. A bog means you're lean. Bog is no power. Hesitation is intermittent power. If you're too rich then you need to move the clip position higher than its original placement to lean it out.

I mention the needle because that's the rev range you described (1/2 to 3/4).

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