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Top End Help!

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Hey guys,

Im only new to two strokes and have had my 06yz250 for 6 months know and think its due for a top end. I have never done one and don't want to make any mistakes can anyone give a step by step procedure on what to do or give me a good link to look at. :ride::applause:

Thanks heaps and may the 2 stroke faith live on!! :applause::thumbsup:

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First of all, unless you ride the crap out of it alot it probably doesnt need a top end.

Get a compression tester and see if it's still within spec.

BUY A MANUAL (FOR SURE!!!!!) it details everything.

But i will give you the basics...

1) Drain coolant from bike, remove all coolant tubes

2) remove exhaust

3) remove gas tank

4) remove intake, carburetor, reed valves

5) remove spark plugs & head

6) remove jug

7) remove piston

8) have jug inspected by machine shop, and have them bore if necessary else just hone

9) order correct piston size etc (with gasket kit)

10) Re assemble & break in

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Thanks heaps and may the 2 stroke faith live on!! :applause::thumbsup:

Quad abusing huh..... :ride:

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Unless you have major hours (50-70) or the bike is harder to start, you don't need a top end. The manual calls for around 30 hours of race time I think. I have an 05 w/120 hours on the motor. I have done two top ends and all is well. These things are strong and durable, I get about 60 hours of engine time before doing a top end. Next, I will pull the engine and split the cases to check the crank, but that will be next year

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You're definitely going to want to pick up a manuel for torque values. Also, you're going to need an extender for your torque wrench so you can torque the cylinder nuts down correctly.

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If you never did a top end job before, try your best to get an experianced buddy to work along side w/ you and the owners manual. It is mostly common sense but you should feel more relaxed doing it w/ someone who has done it before working w/ you.

The above guys gave you good sequence of what to take apart and reassemble. Torque values are important as is cleaning the powervalve. I like to add new antifreeze mixed w/ distilled water and water wetter.

Good luck. :thumbsup:

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