[davidpaul]

Could someone please put into simple English the timing process, I have set the flywheel to cylinder 1 and number 1 piston at tdc and then put the cam sprocket into the correct position, but the manual says about it being the ignition stroke, what do I need to do to make sure it's on the ignition stroke

[NMKawierider]

Could someone please put into simple English the timing process, I have set the flywheel to cylinder 1 and number 1 piston at tdc and then put the cam sprocket into the correct position, but the manual says about it being the ignition stroke, what do I need to do to make sure it's on the ignition stroke

An easy way to look at it is...the crank...and piston only has one TDC but in a 4-stroke engine it takes two full revolutions to complete one cycle so to do all the things the cam has to do in that time period it turns at 1/2 the speed of the crank. OK..so for the cam, there is two points where the piston is at TDC, once is on the compression stroke(ignition per manual) and one at the end of the exhaust stroke. All valve timing is set on its marks for TDC of the compression stroke. One sure way to make sure the cam is in the proper position for that is that no cam lobes or ramps will be touching the rocker arms so all valves will be closed. On the other stroke, which is 180 out, the valves will be on an overlap phase which is where the exhaust valves are almost closed and the intakes are just starting to open. There obviously the cam ramps are touching the rockers.

Hope that helps.

[REDRIDER]

if you put the piston at the bottom of its stroke, then bring it to the top (as long as you are turning it the correct way), the intake valve will close and both valves will be fully closed (rockers down and not moving) while the piston is on its way up to the top as it is making the compression to make the bang (ignition) at the top. if you are on the wrong stroke the exhaust valve will be open while its the piston is moving up then once you get to the top the exhaust valve will be closing and the intake valve will be opening as the piston starts to move back down. intake valve will be close to the intake runner, exhaust valve will be close to where the exhaust bolts on.

[davidpaul]

Thanks guys