It has 30k miles (and I hope not 130k!) it pulls hard but after a valve adjustment I checked the compression.
2: 87 (got it to 90 w penetrating oil)
How concerning is this?
2 and 4 are next to each other with 6 behind them. Not sure if that means anything but just making note of the fact. ?
Well... unfortunately those are ALL low compression readings.
(You did have your throttle locked all the way open when you did the test, right?)
The factory service manual gives a spec of 213 psi for a normal GL1500 engine. The compression test range given in the FSM is 185 psi to 242 psi.
You would only have a reading above 220 or so if you have a really carbon fouled engine. Your current reading are ALL low, so carbon is not the issue.
Low compression can come from three main areas:
1. Worn piston rings
2. Worn/leaking valve seats
3. Leaking cylinder head gaskets
The only sure way to tell exactly what is leaking is to do a leak-down test with a cylinder leak-down tester. A compression tester only tells you if your compression is low. A leak-down tester tells you why. A leak-down tester charges the cylinder being tested with compressed air from an air compressor. Any leak-down percentage results greater than about 8% is a problem. Also, during the test you can listen to where the air is escaping from the engine which will tell you if its rings or valves. If air is escaping through the exhaust system, the exhaust valves are leaking. If air is escaping through the intake/air filter, the intake valves are leaking. If air is escaping through the crankcase, the piston rings are leaking.
I would suspect that the two cylinders that are REALLY low (and next to each other) probably have a leaking cylinder head gasket and the leak is between those two cylinders. All the rest being low could be stuck rings (put in some ring free fluid (like YamaLube Ring Free Fuel additive) and ride that baby! However, it could also be worn rings in the entire engine, which additives will not fix.
Be sure to check your engine oil and see if it looks at all milky. If it does, STOP RIDING the bike until that is fixed! If the oil is milky your cylinder head gasket is leaking and engine coolant is getting into the oil. Note that you can have a cylinder head leak that only leaks to the outside and not into the coolant passages, in which case your oil would look OK, but you could still have low compression in those cylinders.
Even if your bike does have 130,000 miles on it and not 30,000 that should not be an issue with a water cooled Gold Wing engine, unless it was not receiving proper maintenance and oil changes.
A cylinder head gasket replacement is not that hard on a Gold Wing. It does require removing the timing belts, but unless you know when those were last changed, you should change those belts when you do the head gasket.
A Valkyrie is a great Gold Wing! They look bad-azz too! Take your time and and get yours fixed up properly.