how to set timing for OS 300 twin
02-03-2014, 11:38 AM
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how to set timing for OS 300 twin
I have an OS ft 300 twin that I believe the timing is off after I received it back for maintenance. Does anyone know how the camshaft gear meshes with the crankshaft gear for timing. Or how does the hole line up with the dash on the second gear (crankshaft gear) ?
02-05-2014, 07:54 AM
#4
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Very interesting problem. Looking at my 160, it looks as if you would have to put a dial indicator on the piston to determine TDC, and then look at the gears to see where they were, on one that had not been touched since the factory. Since mine is brand new, never been run, I cannot bring myself to take it apart to try to find out. And I have to dial indicator that would work.
Les
p.s. On a closer look, I'm not even sure how my suggestion would work. Very tough problem. Let us know when you find out.
p.p.s. Another look: If you made a 3 or 4 " diameter disk to replace the prop and use for "marking". Support the engine so that a piston is moving vertically (using gravity to an advantage), put a rod against the top of the piston through the glow plug hole, then rotate the crank clockwise until the rod just stops moving upward, and mark that location. Then repeat the operation, rotating the crank counter clockwise until the rod just stops moving upward, and mark that location. Halfway between those two marks should be TDC. If one were to repeat the operation several times, you should be able to be very, very close. I think how close, depends on how accurately you do the job. Again, let us know
Les
Les
p.s. On a closer look, I'm not even sure how my suggestion would work. Very tough problem. Let us know when you find out.
p.p.s. Another look: If you made a 3 or 4 " diameter disk to replace the prop and use for "marking". Support the engine so that a piston is moving vertically (using gravity to an advantage), put a rod against the top of the piston through the glow plug hole, then rotate the crank clockwise until the rod just stops moving upward, and mark that location. Then repeat the operation, rotating the crank counter clockwise until the rod just stops moving upward, and mark that location. Halfway between those two marks should be TDC. If one were to repeat the operation several times, you should be able to be very, very close. I think how close, depends on how accurately you do the job. Again, let us know
Les
Last edited by LesUyeda; 02-05-2014 at 08:28 AM.
02-05-2014, 06:04 PM
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Thanks very much Les! I actually came across an old manual today from another member of my club and that had a diagram still in it. Turns out the dash lines up exactly with the hole on the camshaft gear.But thanks again for the idea, I would have done that next if i still couldn't figure it out!
Ben
Ben
