Timing is everything
It really is. And on the GL1000 it's ever more so. No disrespect intended, but Robert Overby did not discover the split ignition timing technique. Though he wrote about the procedure in the June 1995 issue of Wing World magazine, he was 20 years late to the party, and for that matter was likely not yet born when the method was first endorsed immediately after WWII by BMW for use on their boxer twins. Thus it's no surprise Honda dealer techs were practicing this technique on the GL1000 from almost the Wing's very beginning in 1975 (in a conversation with the Honda factory in 1977 I discovered they knew about it at least as well as I and my colleagues did). It's a great method and far easier to get right than is dynamic timing on this bike. But before attempting points ignition timing on the venerable Wing, there are some things to know. First, tension the camshaft belts as carefully as you can, that will help. But even perfectly-tensioned belts will not prevent the forces of the engine's valve springs and their effect on the left side cam from varying ignition timing. The problem is simply built-in, so do the best you can. I have gone so far as hand-stoning the ignition advancer's lobe to compensate for the variations the soings and belts impose. But though the timing improves, the performance benefit just isn't there. The split timing method's results are just as good. Second, be aware that the longish advancer-mounting snout on the end of the left cam has been shown to often be bent, and this of course adds to ignition innaccuracies. Finally, realize that none of the parts inside the ignition points housing are mounted concentrically with one another. On top of that the mounting surface of the points backing plate is anything but a precise fit. Thus movement of any part within the housing during ignition adjustment takes place eccentrically as well as omnidirectionally in relation to the camshaft. Even if you're uber-careful and meticulous, each succeeding adjustment in the process necessarily upsets the previous adjustment, requiring a back and forth technique, with the goal ever smaller readjustments as you go. Maddening, if you let it get to you. Pros though, through much experience, know how to deal with this.
Alternator connector repair
Many folks bemoan the Wing's tendancy to melt its alternator connector, but few realize why it happens. More importantly, how to repair it correctly, and how to avoid its recurrance. You almost have to have a history with the Honda product, and to some extent all vintage Big Four (Japanese) vehicles, to fully appreciate the issue. And guess what? It's not alternator heat. It's not system load. And it's more a defective manufacturing process than it is a bad part. The fact is, mass manufacturing's wire crimping is the problem, made yet worse by open backed (unsealed) cannon plugs. Exposed to the elements through the old-school plugs, the factory's crimpings steadily oxidize, gradually increasing resistance until enough heat develops to melt the plastic plug. The fix? Address the two issues. Clean and solder the terminals (to their wires, not to each other -- i.e. upgrade from mere crimped to crimped and soldered) and back-fill the plug with grease. If necessary, replace the melted cannon plug, sourcing it from one of the half-dozen online suppliers, several of which I listed in a previous article. The problem will be in the past never to return.
Oh, those rings!
I was blessed to wrench in some heavily-trafficked Honda dealerships in my early years. I somehow quickly commanded the lion's share of the shops' Gold Wing work, along the way developing certain must-dos on services. For example, every time I did a maintenance service I unbolted the intake manifolds and replaced their all-important o-rings. Every time. Ever since then I have had the part number (91301-371-005) etched into my brain from those many years of asking for it from the parts dept. I include these o-rings in the shipment of carbs back to my customers even today. Another critical o-ring point are the two large diameter thin wall o-rings under the aircut valve. I usually glue them to the valve as I know most folks remove the valve during carb reinstall and I want to make it not as easy to lose the o-rings as it might otherwise be. But perhaps the most important o-rings in GL1000 carburetors are those on the push-in primary and secondary main jets. I replace these on every rebuild because they are the first line of defense against fuel mixture issues, seeing as how the jets are a slip fit into their cast aluminum towers. These o-rings are extremely hard to find by themselves, however, and the ones in most kits are incorrectly sized, and crap, no surprise there. The size issue is because, as is usual with Honda, the o-rings are very odd sizes, 3.2mm x 1.1 and 4.2mm x 1.1, respectively. As I say, pretty unique. And none of the half-dozen o-ring houses that have sprung up in recent years have them either. However, there are three retail oulets for these parts imported from Japan, among them Amazon (what don't they sell?) and the best probably being Cycle Recycle in Indiana, who has them for just $1 each. Look for part numbers OR-4604 and OR-4609.
Last edited by mikenixon
on Sat Nov 23, 2019 10:13 pm, edited 1 time in total.