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Singles / Re: M33 1955 - Starting Issues
« on: 24 April, 2017, 21:45:10 »
With the bike on the centre stand, remove the sparking plug, put the bike into 2nd or 3rd, push on the rear tyre in the road direction and when you look at the contact breaker rotor, it will be turning clockwise. Operate the advance retard lever and check what you have to do to move the cam ring in the opposite (anti clockwise) direction. That will be the way to move the lever to full advance - opposite direction to achieve full retard. So now you will know whether you have a "tight" or "slack" cable advance. The other way to check is to look at the contact breaker and if the adv/ret cable is on the right of the CB, then it is a tight cable advance - on the left a slack cable advance. It would be nice if all were the same, but over the years swaps take place, incorrectly as Julian mentions. Extremely important information to know about your bike, both for starting and running.
Now push slowly on the tyre again, with a finger over the plug hole and when you feel compression you know the engine is with the piston rising towards TDC awaiting a spark. Lets check this is happening at the right time? Using a thin rod of some sort, one end resting on top of the piston, SLOWLY continue moving the rear wheel until you reach the highest point the rod travels and mark the rod with some reference point to the outside of the engine. That is TDC. Once found carefully recheck and then with your adv/ret lever in the fully advanced position, turn the engine backwards a little to send the piston partway back down the bore. Once done, this time moving the engine slowly forwards again, mark the rod at the point the contact breaker JUST opens. Measure the gap between the two marks which should be in the order of 7/16 inch. If not the magneto needs re-timing correctly.
Now push slowly on the tyre again, with a finger over the plug hole and when you feel compression you know the engine is with the piston rising towards TDC awaiting a spark. Lets check this is happening at the right time? Using a thin rod of some sort, one end resting on top of the piston, SLOWLY continue moving the rear wheel until you reach the highest point the rod travels and mark the rod with some reference point to the outside of the engine. That is TDC. Once found carefully recheck and then with your adv/ret lever in the fully advanced position, turn the engine backwards a little to send the piston partway back down the bore. Once done, this time moving the engine slowly forwards again, mark the rod at the point the contact breaker JUST opens. Measure the gap between the two marks which should be in the order of 7/16 inch. If not the magneto needs re-timing correctly.