when doing a valve clearance on my yam sr 125 i done as the manual said and lined the [T] mark on the rotor rim to the arrow on the crankcase. the valves were closed tight so set them to the manual setting.started it up and they rattled like fu k.tried again,this time testing piston was at tdc by putting a plastic tie in the spark plug hole.now a mark on the cam chain sprocket seemed to line up with another but the [T] mark was way off.valves were way too lose so set them again this time its ok.is my timing off.the bike is back to the same as it was[dies if you give it throttle].

TDC should be on the firing stroke, ie put your thumb over the sparky hole and feel compression. when you reach the T mark that's when you do the valves.

With the piston on top on compression stroke i.e. valves closed the cam lobes should point outwards and the marks on the cam sprokets should align with the cam casing sides.

when doing a valve clearance on my yam sr 125 i done as the manual said and lined the [T] mark on the rotor rim to the arrow on the crankcase. the valves were closed tight so set them to the manual setting.started it up and they rattled like fu k.tried again,this time testing piston was at tdc by putting a plastic tie in the spark plug hole.now a mark on the cam chain sprocket seemed to line up with another but the [T] mark was way off.valves were way too lose so set them again this time its ok.is my timing off.the bike is back to the same as it was[dies if you give it throttle].