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3rd gear going bad

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:) Anyone know what causes the KX250F to loose 3rd gear? I am working on a bike right now and the problem the rider is having is that when under hard acceleration in 3rd gear the transmission will kick out of gear. Anyone know what to do to fix this? What part usually causes this? What should be replaced? Thanks in advance for your advice.

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:) Anyone know what causes the KX250F to loose 3rd gear? I am working on a bike right now and the problem the rider is having is that when under hard acceleration in 3rd gear the transmission will kick out of gear. Anyone know what to do to fix this? What part usually causes this? What should be replaced? Thanks in advance for your advice.

Sounds like the gear dogs are getting worn down

When you have the tranny apart look at dogs (blocks on the side of thea gear) on 3rd gear, and the gear it mates with. If they are rounded, you need to replace them.

Could also be a shift fork issue, but usually this causes difficult shifting

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just had my 04 engine rebuilt that had a full new set of gears 2nd and 3rd had lost a few teeth

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bent shift fork is probably the cause.

Could be damaged dogs, or a tooth.

But a bent shift fork would also cause this as it maynot be able to fully engage the gear to where it will engage till enough power is applied it drops out. Who knows truly with out splitting the cases.

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Thanks everyone for the replys. I am tearing the engine apart tomorrow. I've already ordered the 3rd gear. Once its apart I'll let you know what I found. It amazes me that this thing is already having transmission issues with only 60hrs on it. :)

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