Need help with valve adjustment

I'm adjusting the valves on my 82 xj650j. When taking the measurement on the back side of the lobe I am finding a lot of variance by moving the cam a small amount. Is there some way to tell when you're at exactly 180 off? I am tight before and loose after, so in or out of specs. with very little movement. I thought that the back of the lobe would be more consistant than that.

 

The lobe on the valve you are checking should be 180 deg from the valve shim bucket. Thats what the service manual shows. I assume you are checking the measurements with the lobes off of 180 and you are concerned that the measurements are not the same as at the 180 mark. Just try to get as close to 180 as possible and write those down and post here. We can let you know what shims you'll need if you can give the numbers off of the ones you have now. Better to be loose than tight in any case.

MN

 

this is why you should use a degree wheel, set it once and it takes all the guess work out of the others

 

My problem is that I'm not sure how to tell when I'm exactly at 180. It is hard to tell visually, and the smallest movement when I'm close (I'm guessing somewhere around 175 to 185) can make me tight or loose. I understand the rest of the process and have a chart to select the right shim, just need help in finding 180. I'm thinking of useing a wood dowell through the spark plug hole to tell when I'm at the top or bottom of the stroke. Is there a better way? Also don't have a degree wheel.

 

I took my measurements, spun the crankshaft, set it up again, then took my meaurements again, then repeat once more. Then use the tightest measurement. Also, look at your firing sequences. You will have multiple intake and exhaust valves closed at the same time.

 

Could you elaborate on this method?
I place a thicker feeler gauge under the cam and hold it so it comes level with the bucket.
Then I try to visualize a 90 degree angle with the top of the cam pointed away from the bucket.
I found using the relation of the cam lobe to the bearing hold down kept my readings consistent.

 

If your cam lobe is off by 5. Deg either way shouldn't be that big of a deal. I would think the heel of the camshaft wouldn't be that far off. I've always just looked at each valve when I do it. No problems so far

 

Shouldn't the feeler gauges be tightest at exactly 180? That's how it looked in the one picture based post bigfitz52 made.

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