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not hitting band!

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i just purchesed a 07 yz250 very crisp indeed with little hrs on the bike, how ever it is not hitting band in 3rd 4th 5th? i no very little about bikes an all ive noticed was a brand new stock powerpipe an a fmf shortie bak end? would it be jetted for a aftermarket exaust and thats why its not hitting band or would it be the powervalve, i aslo have no idea about jetting or the power valve 👍

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it also doesn't miss a beat, no bogging down or bad sounds from the exaust i thought nothing was wrong with the bike till a friend rode it an said it was lacking in power.

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can you provide more details:

- are you sure the "power" is fine in first and second and just not hitting the powerband in 3-5?

- what exactly is it doing in 3-5, does it bog at high rpm but buttom is ok?

It potentially could be jetting but the jetting would have to be way way off for it cause such a noticable power difference.

IMO it sounds powervalve related (and not specific to gears 3-5) and I'm betting its been a while since the last top end (since you just picked up the bike, you cant know for sure).

If so, throw a new top end in and while your cylinder is off give the power valve a good cleaning and make sure its working, it sounds like it could be gummed up and stuck closed.

Very simple and cheap maintenance.

The RMATV videos will help you to do a top end in your 2t yz: (btw the bike in this video is almost exactly the same as the one you have)

http://www.rockymountainatvmc.com/videos.do?videoId=90

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i live on the gold coast, i had a 2001 before the 07 and it went alot faster, my mates 06 is level with me till around 3rd then he pulls away quite fast but my bike doesn't seem like there is anything wrong sound wise, no spluttering or anything it jst doesn't have the go like the 3 other yz250's i ride with.

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also thanks for that link always wondered how to do a top seems simple enough.

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it could be a few things or a combo of both. you could have a weak topend meaning you need a piston and ring. you could be jetted too fat up top like all the other yz's in the world.

cleaning the carb is a good place to start. seeing what the jetting is and also what mixture oil/fuel are you running?

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Pop off the powervalve cover and make sure the screws holding the assembly together haven't backed out. Apparently this is fairly common.. It's easy to check, if the PV assembly is in good working order, than go with what others are suggesting.

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Sounds like your PV may not be fully opening... its sometimes more "noticable" in higher gears. Open the cover and take a peek.

Everyone has already covered the jetting. Check that out as well.

Also make sure someone didnt gear it for low end. That could be another reason they pull on you in higher gears.

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My brother's bike was hitting the "band" either in some gear recently and it ended up being a simple fix. We had recently put ASV levers on the bike and had the clutch cable adjusted to tightly. Make sure the clutch lever has some play in it. Turns out we had it to tight so the clutch never fully let go in some gears not allowing the full power to be put down. A two minute fix of readjusting the cable to put some slack in the lever was the trick. Give it a shot, doesn't waste much time.

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