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Surging commom to 2 strokes?

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I used to ride a '96 CR250 but sold it to get an ATV a few years ago. I really miss having a dirt bike and want to look for an '01 CR250. My only concern is using it to cruise on fire roads. I remember with my '96, if I tried to hold a constant speed on a straight trail it would surge. As long as I was accelerating it was perfectly smooth. Is this common to all 2 strokes?

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no you have a carb issue, needle clip position and needle size would change this, leaness causes surge.

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Ok. Because I've heard that the powervalve might have something to do with this. Something about how it doesn't know whether to open or close, so it is constantly going back and forth at a constant throttle setting while cruising down a trail. Has anyone else ever heard this?

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I know exactly what you are talking about. When I first got mine, I would try to cruise on gravel roads and it would surge. I either had to be a little on the throttle or totally off. I just accepted it. Then I was trying to get rid of my spooge issue so I changed my jetting. When I got my jetting perfect the surging stopped.

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Since there is relatively little flywheel mass, and the engine makes power every other rotation, vs. every 4th like 4-stroke, it makes power very frequently without having a lot of mass to keep the crank turning... so it definitely has the feeling of surging or continually accelerating.

My YZ250 is jetted and very fresh, and I find it either accelerates or decelerates... I haven't found the constant speed equation for cruising, but it once I became used to the way it makes power, I can ride it anywhere without issue. I have heard a flywheel weight will lessen this effect and make the bike easier to ride... mine comes in tomorrow. =)

Check and see what years have more mid-range. I know Yamaha (ducking from stones) made significant changes to the powerband of the bike in 2003 which gave it way more low-mid range power.

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Hey V1, you're right. I forgot I also put on a big FWW so that had to help.

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Since there is relatively little flywheel mass, and the engine makes power every other rotation, vs. every 4th like 4-stroke, .

A 2 stroke makes power on EVERY stroke a four stoke makes power every other stroke :)

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cruising on a 2 stroke? I'll have to try it. I thought it was gas or brake no cruising!

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Surge, indicates a lean condition. You can ring the nuts on a 125 w/out any surge.

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