Baby's first leakdown test

I still can't find the source of this idle surge on the '76 GL1000, so I decided to start from scratch.
I ran a leakdown test on all the cylinders at TDC to check for valve issues. I could have pulled the camshafts and performed the test throughout the piston's movement range to see if there's a particular problem spot on the cylinder walls or piston rings but I'll wait on that for now and just run a compression check next.

Since the plugs were out I decided to check them.
They look a little dark so at least it's not a lean condition.
Most importantly they're all the same color.
This is evidence against an intake runner leak on one carb.

Here are the results of the compression test:

Click for full size picture.

Cylinder	InputPSI	LossPSI	LossPSI (2)	%Lost	%Lost(2)
1	90	86	85.5	-4.444444444	5
2	90	86	85	-4.444444444	5.555555556
3	90	86	86	-4.444444444	4.444444444
4	90	88	88	-2.222222222	2.222222222
1	80	75.5	75.5	-5.625	5.625
2	80	75	75	-6.25	6.25
3	80	75.5	76	-5.625	5
4	80	76	76	-5	5
-	-	-	-	-	-
1	70	66	66	-5.714285714	5.714285714
2	70	64	64	-8.571428571	8.571428571
3	70	66	66	-5.714285714	5.714285714
4	70	66	66	-5.714285714	5.714285714
-	-	-	-	-	-
1	60	56	56	-6.666666667	6.666666667
2	60	55	55	-8.333333333	8.333333333
3	60	56	56	-6.666666667	6.666666667
4	60	56	56	-6.666666667	6.666666667
-	-	-	-	-	-
-	-	-	-	-	-
1	90	86	85.5	-4.444444444	5
1	80	75.5	75.5	-5.625	5.625
1	70	66	66	-5.714285714	5.714285714
1	60	56	56	-6.666666667	6.666666667
2	90	86	85	-4.444444444	5.555555556
2	80	75	75	-6.25	6.25
2	70	64	64	-8.571428571	8.571428571
2	60	55	55	-8.333333333	8.333333333
3	90	86	86	-4.444444444	4.444444444
3	80	75.5	76	-5.625	5
3	70	66	66	-5.714285714	5.714285714
3	60	56	56	-6.666666667	6.666666667
4	90	88	88	-2.222222222	2.222222222
4	80	76	76	-5	5
4	70	66	66	-5.714285714	5.714285714
4	60	56	56	-6.666666667	6.666666667

It's important to note I performed this test on a cold motor. It's generally better to warm up the motor first as your numbers will be more accurate. However, there were still no glaringly obvious problems indicated by these results.

I suppose the next move will be to compression check the cylinders and see if they are good in that aspect.