B250 Valve Clearances and Timing Specs

[PitterB4]

Valve Clearance when cold

Inlet: 0.10 - 0.15 mm or .004" - .006"

Exhaust: 0.15 - 0.20mm or .006" - .008"

Cam Timing

With engine at TDC (remove right side crank end cover and line up T mark) on No1 cylinder (left side as sitting on bike) look for the number 1 on the exhaust cam sprocket, 1 must face towards front wheel and be perfectly horizontal to valve cover gasket surface. Import is that the chain is tight between this sprocket and crank sprocket on the front side of engine. Then position the inlet cam sprocket so that the number 2 (stamped in sprocket like No 1 on exhaust sprocket etc) is also paralell to gasket surface and again pointing towards front wheel.

Now on the front cam the number 2 will be pointing vertically up, from the tooth directly above this number count 20 pins in the timing chain at which point you should be directly over the inlet cam sprocket and the number 3 which is vertical, engage chain with 20th pin in sprocket tooth above the number 3. All loose chain is to be between the inlet spocket and the crank ie at the back on the motor. Once all cam journals have been tightened etc then the chain tensioner can be reinstalled once it has be rewound with a screwdriver.

DO NOT RELY ON THIS INFO, I HOLD NO RESPONSIBILITY for the accuracy of this even tho it was taken directly from the manual.