VALVE adjustment lobe position

[moparman70]

Just wondering the correct way --- Randy you are probably the expert.   My manuals call for the valve measurement to be done on Compression Stroke at TDC --- and when done ( alignment of the "T" on the on the ignition pick up coil) The cam lobes will face away from the lifters but they are not 180 away.  All four though are off the lifter and point outward.

In my case all four the cam lobes are 90 + degrees out -- the bottom of the lobes are facing inward with tops pointing out more sideways.

I have been told some don't do the above but just make sure the cam lobes are 180 out from the face of the shims -- pointing straight up more or less but and the same angle of the valves themselves.   With this method you have to turn the engine more to get each set in that position.   More importantly when I measure each way the values were different thus it could mean doing it one way or the other would be wrong.

In a nutshell -- where are the cam lobes when you measure the clearances --- the book method they are not 180 out from the shim so which is correct?

Steve

[FJscott]

Just wondering the correct way --- Randy you are probably the expert.   My manuals call for the valve measurement to be done on Compression Stroke at TDC --- and when done ( alignment of the "T" on the on the ignition pick up coil) The cam lobes will face away from the lifters but they are not 180 away.  All four though are off the lifter and point outward.

In my case all four the cam lobes are 90 + degrees out -- the bottom of the lobes are facing inward with tops pointing out more sideways.

I have been told some don't do the above but just make sure the cam lobes are 180 out from the face of the shims -- pointing straight up more or less but and the same angle of the valves themselves.   With this method you have to turn the engine more to get each set in that position.   More importantly when I measure each way the values were different thus it could mean doing it one way or the other would be wrong.

In a nutshell -- where are the cam lobes when you measure the clearances --- the book method they are not 180 out from the shim so which is correct?

Steve

When I do mine I set the clearance at the base circle of the cam. Lobe at 180 from the valve stem.
Scott

[Fj.itis]

Yep, same same.

[moparman70]

I checked another book the Clymer and it has the same procedure but does show a diagram with the cam lobe at 180 --- but if you follow the book it doesn't happen that way.   I just wish both methods had the same clearance readings.

[movenon]

I do mine as per Yamaha Service manual. The lobes are facing side ways. If the timing mark on the rotor is TDC and the index marks are visible through the inspection holes in top of the number 3 intake and exhaust cam caps your lobes should be facing sideways.  Not an expert, just a guy in the garage....
George

[racerrad8]

Point the lobes straight away from the bucket/shim, this will ensure you are at the base circle of the cam.

It will also compensate for timing chain stretch which could be an issue if using the crankshaft timing marks.

Randy -RPM