I just bought a 1983 GL1100 Interstate. 74k miles, it had been sitting (I think in a garage or storage based on the very low levels of rust) for probably a good ten years before the PO bought it for peanuts and refreshed it. I bought it from him and have been riding it around a bit to get a feel for it. I like it a lot, especially since I normally ride a large displacement sportbike and like the revvy 1100. The 1983 has a nice highway RPM at 70-75mph and it has lots of power. Much more than I expected. So, very happy with my purchase.
I used forums like this one to scout out all the stuff to check for - things like the alternator providing good current, what kind of condition plastics generally are at this age, air suspension holding pressure, etc... So I'm already in your debt.
There are a few things I wanted to ask - just since I've never owned one of these before.
1. It pulls like a train above 4k. Never seems to run out of breath, even to redline. Woohoo! It pulls decently strong from 3k-4k, too. From 2k-3k it's usable, but sluggish. It idles at just under 1k, but from 1k to 2k it has almost no power at all. I've been just bringing RPMs to 2k when launching from a stop and they really never get below that when riding it. It's not a problem for me as long as it's normal. My (somewhat) modern sportbike has very strong torque from idle all the way to redline, but every engine design is different, so no big deal if it's just not supposed to have any power until you hit 2k (or 2.5k to get a good strong launch).
2. At idle (1k), the engine rocks very slightly from side to side. It's not in danger of dying or anything, and the effect is slight - nowhere near the idle drama of my friend's Harley, which shakes and rattles like an angry dragon. It's more like a soft, inertial rock. Is this bad? Does it matter?
3. When it rocks at idle, it makes a bit of a tapping sound that is timed to the rocking. It's not loud, but it's noticeable. Again - bad? Does it matter?
4. I'm going to need a taller windshield. Any recommendations on where to look? I'm pretty tall - at highway speeds if I duck down about 4-6 inches it's dead quiet, but otherwise I'm in the turbulence above the screen. It doesn't have to be taller as long as it does a better job of pushing the air up away from the top of my helmet.
5. The tires have deep tread and show no sign of dry rot. But they're 13 years old, according to the date code. I can assume they are unsafe, right?
6. Last one - for now. The timing cover gasket has a gap in it where it looks like the gasket has been damaged/clipped somehow. I put some electrical tape over it just to make sure no dirt or debris got inside. Is this something that should be replaced urgently? The gasket gap is about 5 inches long along the side. Timing cover and engine seem undamaged, so I'm guessing this happened with the PO refreshed it. He said the first thing he did was change the timing belts.
Anyway - glad to be a GoldWing rider. I already feel like a part of a vast conspiracy of comfortable riding.
EDIT: Just to clarify question 1 - On my friend's Harley and on my sportbike, if I slowly let out the clutch the bike will slowly pick up speed. If I don't mind launching slow I can do it without using the throttle. On the GL1100, if I slowly let out the clutch the engine lugs and dies (and the light tapping sound gets louder). It does not have enough off-idle torque to get the bike moving. At 2k and up it's smooth sailing. Pulls forward just fine - I just have to slip the clutch a bit while keeping revs right around 2-2.5k, and it launches like a champ. And again - at 3k it feels very strong and at 4k it feels very similar to my sportbike. I have to lean forward to keep my arms from being yanked if I open the throttle while at 4k. I have zero problem with this if it's normal. I just don't want to damage the bike since, yaknow, I just got it and all!