Questionhi wondering if you have the tightening tension for cylinder head and timing marks for xr350
AnswerKylie, bolt torque is usually determined by the size of the fasteners, the grade of the material and thread pitch.
http://www.engineershandbook.com/Tables/torque1.htm
If you have 8mm studs/nuts, they are usually grade 8 parts (generally they have a mark on them), the torque is about 15-17 ft lbs. with dry threads.
I assume you are asking about cam timing and not ignition timing for your engine. On a single cylinder engine, the key is to have the piston at the top of the cylinder (T mark on flywheel), then position the camshaft so that the cam lobes are directly DOWN / \, which allows the valves to be closed on compression stroke. I don't have specifics on XR350 engines, but generally Honda marks the camshaft sprocket with either a o mark, to be placed at 12 o'clock position with crank at T mark. Sometimes, they put horizontal lines on a sprocket, which would then be placed so that the lines are parallel with the cylinder head cam cover surface =O=
Usually the camshaft sprocket bolts will line up vertically when the cam timing is correct. I went to
http://houseofmotorcycles.bikebandit.com/honda-motorcycle-xr350r-1983/o/m9706
guessing at the year, and see that the sprocket bolts will line up vertically, according to the drawing.
Once you install the camshaft bolts, just tighten them gently and then turn the engine over one turn, which should have the cam lobes aimed upwards at the T mark alignment. Turn once more to get the lobes down, allowing for easy installation of the cam cover and the rocker arms. Be sure to check and adjust the valve clearances in this position.
Once the valves are adjusted, turn the engine over 2 turns, with a wrench on the crankshaft bolt, very slowly, to be sure that you have cam timing correct and no valve/piston collisions are going to happen.
Bill Silver
