Edward Buck
CB750 Enthusiast
Hi, I'm setting the tappet clearances on my K4 750 - I've rebuilt a K1 a couple of years ago and I find I have the same issue I had then - I just can't recall the solution.
The manual says to set the no1 cylinder tappets with the slot in the end of the cam shaft at the 12 o'clock position and the timing marks on the crank showing 'T' position against the static timing mark - you are supposed to be able to set the no 2 exhaust and no 3 inlet at the same time. However whilst I can just about set the no 1 cylinder tappets there is no way to do no 2 and 3 cylinders as they are opening the valves. If I turn the camshaft so that the slot is in the 6 O'clock position then its spot on for adjusting no. 1 and the other two at 2 and 3 cylinders. I know that the bike sparks on both the exhaust and compression cycle so it shouldn't make any difference to the firing.
Why does the manual say to do it with the slot at 12 0'clock position - if you look at the the cam lobes on no 1 cylinder in this position (see photo) they are clearly not on a compression stroke as the lobes are both pointing upwards? Surely you adjust with the cam lobes pointing downwards as this does allow exhaust 2 and inlet 3 to be done at the same time?
I have read about 50 threads on this site and SOHC site and lots of people seem to come across this - anyone know why the manual says to do it this way?
Experienced hands will say its easy just do them one at a time on the compression stroke - I just want to know why the manual says to do it the way it does.
I wish I could recall what I did on the K1 as it runs sweet as a nut.
Engine is out of the bike on the bench so early easy to access everything. Photos below of engine at TDC on static mark and Cam in 12 o'clock position - lobes point upwards??
The manual says to set the no1 cylinder tappets with the slot in the end of the cam shaft at the 12 o'clock position and the timing marks on the crank showing 'T' position against the static timing mark - you are supposed to be able to set the no 2 exhaust and no 3 inlet at the same time. However whilst I can just about set the no 1 cylinder tappets there is no way to do no 2 and 3 cylinders as they are opening the valves. If I turn the camshaft so that the slot is in the 6 O'clock position then its spot on for adjusting no. 1 and the other two at 2 and 3 cylinders. I know that the bike sparks on both the exhaust and compression cycle so it shouldn't make any difference to the firing.
Why does the manual say to do it with the slot at 12 0'clock position - if you look at the the cam lobes on no 1 cylinder in this position (see photo) they are clearly not on a compression stroke as the lobes are both pointing upwards? Surely you adjust with the cam lobes pointing downwards as this does allow exhaust 2 and inlet 3 to be done at the same time?
I have read about 50 threads on this site and SOHC site and lots of people seem to come across this - anyone know why the manual says to do it this way?
Experienced hands will say its easy just do them one at a time on the compression stroke - I just want to know why the manual says to do it the way it does.
I wish I could recall what I did on the K1 as it runs sweet as a nut.
Engine is out of the bike on the bench so early easy to access everything. Photos below of engine at TDC on static mark and Cam in 12 o'clock position - lobes point upwards??
