#1-Properly serviced carburetors
Obviously the carburetors must be clean, but did you know this includes the idle jet? Many don't even know where the idle jet is, or how to remove it for cleaning and vetting. The idle jet, at just 0.35mm size and due to the size of the engine and the bike's gearing, affects a good portion of the practical operating range of the carburetor, and consequently is the most critical jet. Its outward dimensions are tiny also, making it easy to overlook. And, I always "size" the idle jet, meaning I measure its orifice. Another thing a properly rebuilt carburetor means is having the correct air bleed jets in place. This can be a challenge as replacements are hard to find on the aftermarket, the ones in kits (ugh!) are usually incorrect, and the jets' correct placement in the carburetor is somewhat non-intuitive. The larger bleed jet goes in the smaller primary main circuit and the smaller one in the larger secondary main circuit. Another thing folks miss in carb rebuilds is the GL1000 has a very unique float setting procedure. Unlike the GL1000 carburetors' cousin the CB450 twin and the similiarly notched CB750, the float gauge is NOT inserted into the cutouts (notches) in the carburetor casting (body). Doing so will set the floats considerably richer than stock. Also, GL1000 carbs need their pilot (idle mixture) screws set richer than what is intuitive. Slightly rich makes up for two things GL1000 carburetors suffer from. By design, the carbs are actually too large for the engine. Making the pilots slightly richer than your ear or even an exhaust gas analyzer would indicate will compensate somewhat for these design shortcomings.

#2-Properly serviced ignition
In my more than fifty years in this industry, I have installed virtually every kind of aftermarket ignition system available: Martek, Prestolite, Maxi, Gerex, MSD and many more. But in the end, I always came back to the stock system as my preferred ignition. And I emphasize "stock." Not Daiichi crap. Once properly set up, the stock point system is more reliable than an aftermarket system, just as powerful, and very low maintenance if initially set up properly. The points don't need replacing any oftener than 20,000 miles if OEM and dressed and checked every 3,000. Even if the ballast resistor is removed, which I did pretty often in those days. The problem is, very few people are capable of properly adjusting the GL1000 ignition. Whether using the split timing method (which all good techs were using within a year of the bike's introduction), the "bombsight" tool, or any other method, most folks just seem to have a lot of trouble with this procedure. And it matters. A lot. This is this engine's Achilles' heel. You also want good spark plug caps. Every GL1000 I have serviced in the past 20 years has had faulty caps. As well as caps that were loose on their wires.

#3-Spec cylinder compression
I cringe when someone says, "at least they're close together!" In contrast to what many forums seem to promote, having the cylinders close to equal takes a distant back seat to having proper numbers. The numbers are important. If you can't get 150 psi out of your engine, don't spend time or money on any other part of the motorcycle. And don't bother checking compression hot, don't mess around with oil and any other tricks. Just hold the throttle wide open and with a well-charged battery see what you can get.

#4-A clean fuel tank
The problem with the Wing fuel tank is it is not easy to remove, which means it will likely not see the service it needs. Get after any rust in your tank. Some folks report good results from in-situ reverse electrolysis. Others use one of the modern non-acid solutions. Either way, don't depend on your fuel filter to be your carbs' only defense against rust.

#5-Good electrical connections
Fifty year old motorcycles can have frighteningly bad electrical connections. One place you may not have thought about however is the keyswitch. The factory switch does go bad eventually and the aftermarket ones are typically much worse. Do a quick check of your keyswitch by putting a multimeter set for low DC Volts across the red and black contacts. Turn the key ON and note the reading. You want less than 0.2 volts as a reading. The value displayed is the drop, the loss, across the switch. Another common dirty connection is at the engine stop ("kill") switch. Same test. Voltmeter across the black and black/white wires. Key ON, kill switch ON, take a reading. Again, you can allow up to 0.2 volts. More means the switch or its connectors are corroded or dirty. The contacts themselves may be grungy (the kill switch is exposed to atmosphere full tine) or its wire connectors may be dirty. Everyone has heard of folks installing Bosch type relays between their keyswitch and ignition coil. I don't favor that, viewing it as a bandaid fix for otherwise dirty connectors.