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350TSS · 21-01-2020, 08:59 AM

Thanks Phil for the kind offer, I do not think I need you to take the trouble.
My plan of action is as follows:
First I will set the adjustable camshaft pulleys in the middle of their range of movement, there are no timing marks on these pulleys at present so I will compare the keyway position on the old pulleys with the new ones and make corresponding marks on the new ones.
I will determine true Top dead centre by using the stop method, inserting something in the plughole which will stop the piston at some point before TDC and noting what the degree disc says then turning the engine backwards until the piston stops again. TDC is halfway between the two positions where the piston stops.
Having established true TDC (as opposed to a possibly inaccurate TDC indicated by the marks on the flywheel) I will make sure that the jack shaft pulley is completely aligned with the timing mark on the crankcase. I have already found there is about a couple of degrees of slop on the pulley so the pulley nut will be done up when the engine is at true TDC and the marks are aligned.
The next issue is that I have no static marks on the inner belt pulley caps because I have binned them.
This is where my process gets a bit flakey.
Studying pictures of the original assembly the vertical cylinder inner cam belt timing mark is at about 09.30 on the big hand of an imaginary clock if the clock face is aligned between the centres of the upper and lower pulleys. This is where I will set my newly marked adjustable pulley as I put the belt on. A similar process for the horizontal cylinder.
Unlike the 4v design there is no danger of the valves hitting each other if the timing is wrong because the single cams are ground so that the valves do not collide. I will turn the engine over slowly to establish there is no possibility of a valve vs piston collision.
The next task is to establish the position of the crank shaft when peak opening of the inlet cam occurs and to do so for both cylinders.
Assuming that my DTI cannot measure the full range of valve movement I will have to determine where the DTI stops turning but the valve is still descending and record the reading on the timing disc, then rotate the engine backwards about 600 degrees and record where the DTI starts to move as the valve closes. Peak valve lift will be halfway between the two.
I will compare the results for both cylinders with the specification for the camshaft fitted and adjust the adjustable pulleys accordingly.
It will probably take me about a week.

21-01-2020, 08:59 AM	#1104
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,419	Thanks Phil for the kind offer, I do not think I need you to take the trouble. My plan of action is as follows: First I will set the adjustable camshaft pulleys in the middle of their range of movement, there are no timing marks on these pulleys at present so I will compare the keyway position on the old pulleys with the new ones and make corresponding marks on the new ones. I will determine true Top dead centre by using the stop method, inserting something in the plughole which will stop the piston at some point before TDC and noting what the degree disc says then turning the engine backwards until the piston stops again. TDC is halfway between the two positions where the piston stops. Having established true TDC (as opposed to a possibly inaccurate TDC indicated by the marks on the flywheel) I will make sure that the jack shaft pulley is completely aligned with the timing mark on the crankcase. I have already found there is about a couple of degrees of slop on the pulley so the pulley nut will be done up when the engine is at true TDC and the marks are aligned. The next issue is that I have no static marks on the inner belt pulley caps because I have binned them. This is where my process gets a bit flakey. Studying pictures of the original assembly the vertical cylinder inner cam belt timing mark is at about 09.30 on the big hand of an imaginary clock if the clock face is aligned between the centres of the upper and lower pulleys. This is where I will set my newly marked adjustable pulley as I put the belt on. A similar process for the horizontal cylinder. Unlike the 4v design there is no danger of the valves hitting each other if the timing is wrong because the single cams are ground so that the valves do not collide. I will turn the engine over slowly to establish there is no possibility of a valve vs piston collision. The next task is to establish the position of the crank shaft when peak opening of the inlet cam occurs and to do so for both cylinders. Assuming that my DTI cannot measure the full range of valve movement I will have to determine where the DTI stops turning but the valve is still descending and record the reading on the timing disc, then rotate the engine backwards about 600 degrees and record where the DTI starts to move as the valve closes. Peak valve lift will be halfway between the two. I will compare the results for both cylinders with the specification for the camshaft fitted and adjust the adjustable pulleys accordingly. It will probably take me about a week.