Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Fogdevil on April 22, 2018, 08:41:27 PM
-
Just wondering if you could help me get something straight in my head.
I have just timed the camshaft (T1-4 marks correspond,cam sprocket lines parallel with top of barrel,cylinder 4 cam lobes pointing down)
Next job is to fit the head and adjust tappets.
According to the manual you first adjust cylinder 1 tappets at TDC with valves shut. BUT if I leave the camshaft in the same position(as above) the cam lobes are pointing up therefore valves are open.
SO-do I have to rotate crank until cylinder 1 TDC and lobes face down.If so,why does workshop manual(p20) show you cylinder 4 with lobes in down position for timing purposes?
OR-do I adjust tappets at cylinder 4 first and do it the opposite way to the manual
Am I overthinking this?
-
This nay help you as I couldn't make sense of it either so K2-6 (Nigel) enlightened me when I built my engine.
The camshaft positioning (up or down lobes) is not important. With the crank set at T for cylinders 1 and 4, both of these are at tdc. Camshaft one way will give firing on one cylinder and exhaust on the other, then flip the cam 180 degrees without moving the crank, and the sequence just flips cylinders with it. As they are both sparked at the same point it makes no difference which way you build it.
But there again the above may confuse issues even more
::)
-
Out of interest and to satisfy my curiosity, if you are sat on the bike, which is number one cylinder,left outer or right outer?
-
Out of interest and to satisfy my curiosity, if you are sat on the bike, which is number one cylinder,left outer or right outer?
As your sitting on the bike No 1 is to your left, or the nearside. No 4 is to your right, or the offside.
-
Thanks for the clarification Julie.
-
It wouldn't matter if 1 was on the right, as 1 and 4 go up and down together and spark together. Just saying ;)
-
It wouldn't matter if 1 was on the right, as 1 and 4 go up and down together and spark together. Just saying ;)
I confused myself recently whilst setting the tappets, easily done in fairness... :) I was just interested.
-
But.. while you can happily time the ignition on the wrong stroke, because of the wasted spark, but you can't do the tappets on the wrong stroke, believe me I've tried.
It doesn't matter when you're building it, because the engine doesn't 'know' which stroke is which until you time the cam. Once you have timed the cam you want to be doing the tappets on the cylinder where the pointy bit is on the opposite side to the cam follower, ie you are on the base of the cam.
I got confused about the 1 - 4 sequence at first, (despite it being written on the plug leads), think of it as when you are sat on the bike, its the same way round as you would write 1-2-3-4 on a piece of paper if you put it on the tank in front of you.