Ignition Timing

[Guzziando]

Hi, yes it does have the woodruf key, but there was some play. I am however now completely confused (easily done!). When I took the cam belt off, the camshaft sprocket mark was pointing at the TDC mark (top of the case). Both valves were closed. They are now both open, and to get to a position where both valves are fully closed, the cam has rotated through 180 degrees? No idea how this could have happened. The sprocket on the cam is keyed on (I am assuming so)

Any ideas?

[MickeyMoto]

At tdc on the compression stroke on the front cylinder the dot on the camshaft wheel is 180 degrees from the tdc mark on the crankcase. At this point the dot on the crankshaft sprocket should align with the dot on the crankcase.

Well, that was how mine was when I changed the belt two weeks ago

One thing to look at is when the cambelt is removed the camshaft will turn as cylinder 2 is somewhere in its cycle and a valve will be open to some degree and the spring tension will unwind pushing the cam around. I always check the crank mark and set the cam dot 180 degrees from the tdc marker before fitting the belt and then checking it with the belt partially on.

[Guzziando]

I have now removed the nut holding on the camshaft. The woodruff key appears to be there, so I will reassemble it. The sprocket is tight on the shaft, and if it is keyed in place, I am happy that it is not moving, and is in the right place, as there is only one slot.

PXL_20250822_145350276 (1).jpg (498.94 KiB) Viewed 2 times

[MickeyMoto]

If this is in response to my above post, then the slot is irrelevant. The dot on the camshaft pulley needs to be at the bottom (180 degrees from the notch on the crankcase where the ignition timing is set) when the crank is at tdc on the compression stroke of No. 1 cylinder i.e. the Woodruff key on the crankshaft for the rotor is pointing to the dot on the crankcase. I can see the dot on the camshaft, which appears to be about 30 degrees out) and the dot on the crankcase but not the position of the Woodruff key on the crankshaft.

I have no photos to explain, but my bike has just done 136 miles with the pulleys as above.