My dt125 01 plate has blown a ring on 2 pistons in the same place, the remains of the ring goes out the exhaust but it hit the power valve on the way out scoring the piston, the crank area is now making a noise only when reving, not on tick over. can u help pls as shops dont know the problem.

SOURCE: 1998 yamaha grizzly engine noise

you may have a collapsed lifter

SOURCE: VN900 CLASSIC VALVE CHECK. When checking

You can do it if you catch tdc on the correct stroke, but it's always better to rotate the engine after each adjustment.

SOURCE: yamaha tw. noise from engine

Check and reset (if needed) the valve clearances. With the engine cold, set the intake to .002 and the exhaust to .003. Is the cam chain tensioner set properly? Burn premium gas and install a new NGK spark plug one heat range colder than stock to lessen any possible pre-ignition. Are there any signs of wetness, oil or blackish discoloration on the base of the cylinder head? > A blown head gasket can make a ticking sound also.

Please rate this solution. Thanks Kenneth!

SOURCE: Yamaha Power Valve System

yes you do need a battery, the best position for thr power valve is half open, then once its started turn it either open for bottom end power or closed for top end,i think that right it might be the other way round ant quite remember, but half open should be best for it to start

SOURCE: iv just bought a tzr 125 belgarda its smokes like

There are two places where gearbox oil can leak into the combustion process: from the gasket between the two engine case halves, or from the crank seal on the right hand end of the crankshaft. The most likely culprit is the crankshaft seal.