® Wing Tips # 1

Compression covers a multitude of sins
Vintage Gold Wings don't have the problem with low cylinder compression that other old Hondas have, due to their valves being made much better. But they still can have problems with compression. The very first determination in any revival effort is to square away cylinder compression. If lower than 150 psi, loosen your valve clearances 0.002" to get some of it back, and in the mean time perform cylinder leakdown tests to pinpoint the actual issue. Compression is extremely important, but not for the reason you might assume. Cylinder compression directly affects carburetor mixture. Higher compression makes carburetion richer, lower compression makes it leanner. Literally. This is not exactly intuitive, but true nonetheless. It is a fact that 90 percent of the modifications folks make to their carburetors are attempts to unknowingly compensate for engine shortcomings, especially lower than normal cylinder compression. Compression really does cover a multitude of sins, making up as it does for less than perfect carburetion. This is not theoretical, but a fact I and others have proven countless times. Start with compression.

Ignition, the heart of your engine
One area compression can't compensate for is inaccurate ignition timing. I once exchanged emails with someone for almost a year helping him solve a performance problem, only to have him admit in the end he had steadfastly avoided even considering his ignition system, despite my repeated insistence. People consistently do this, and I am not sure why they do it. The ignition system is without a doubt the weakest part of the GL1000 Gold Wing. Not a bad part, just a weaker one needing a level of effort and skill that few possess, even professionals. I doubt I met more than three people in nearly 20 years of working as a shop mechanic who could do the job right, and these were career guys! Ignition service is extremely important. I frequently tell people they have no business yanking their carburetors off until they have properly set up their ignition system. And it isn't just timing I am talking about, though that is the main thing. Timing at both idle and 2500 rpm, of course. But also high quality points, not the all-too-common junk foisted on us these days -- even by Honda themselves. Timing that is off by just a few degrees will be felt, believe it. And having a Dyna or another electronic points replacement system fitted doesn't get you off the hook. It still has to be timed, for one thing. And timing a Dyna is nearly as much work as doing the same job on factory points for the Dyna does not come in the box properly set up. Not even its pickups are guaranteed to be 180 degress apart like they should be. Plus many aftermarket ignitions adversely affect (shorten) the advance curve and this must be accounted for during installation. Do this right. After compression is ignition timing.

The idle jet rules
No other carburetor circuit, and no other part of the engine, for that matter, makes as much difference performance-wise as the carburetor's idle jet. But it can be a challenge. It is the smallest jet in the carburetor. It is buried the deepest and often pretty difficult to remove. It's hole is only 0.013" in diameter, meaning this: unless you just removed and cleaned it, count on it being at least partly blocked. Guaranteed. And lastly, the idle jet affects not only idle but also starting, accelerating from a stop, and even cruising -- yes, cruising (at low load and low rpm). Nothing is more critical to a pleasant-performing bike. Make sure the jet is clean, and this does not mean merely blowing air through it. Also make sure the idle circuit's air bleed jets under the vacuum piston are the correct sizes. The idle jet really does rule.

The truth about air bleeds
Speaking of air bleed jets, the GL1000 carburetor has of course three different removable air bleed jets. Again, its car origin. The primary main circuit has one, the secondary main circuit another, and as just mentioned, the idle circuit has its own. Three differently placed and differently sized air bleed jets. Times four of course. Times five year models, as each varies. (Let's see, that's 60 possible ways to screw up). Goofy carb kits, goofy literature and even goofier "professionals" get this all wrong. You must have the correct jets in the correct places for good carburetor performance. Easily every third set I receive for rebuild has them messed up. Make sure they're right.

Avoid the notches
Speaking of rebuilds, the GL1000 has a unique float setting procedure. On the carb that the wing carb is related to, that on the 1960s-1970s CB450 twin, and in fact many other Honda carbs of the era, the float setting tool is allowed to enter into and rest in the gasket-retaining notches cast into the sides of the carburetor. But the very similar appearing GL1000 carburetor actually came from Honda's 600cc car, and thus there is a completely different ethic. The tool must not be placed into the notches or the setting will be incorrect. It will be way rich. Blame this inconsistency of similar carbs but different techniques on the car division at honda.

Look out for twisted throttle shafts
the GL1000's carburetors have fairly small diameter throttle shafts made of brass that are chrome-plated. A slit is machined along much of the shaft's length to receive the throttle plate. And don't forget that on one side of the carbs, these shafts stick out quite a bit, making them easy to grab. These three things together -- the soft brass material, the reed-like result of the machined slot, and the long shafts' ease of access -- make this shaft extremely vulnerable. Add to this the Wing's propensity for flooding its air plenum with fuel when a float valve malfunctions, laying down a LaBrea tar pit -like blanket of petroleum-based epoxy, sometimes an inch thick, and you have a common problem. Someone tries to force the throttles open, this twists and sometimes breaks the throttle shafts, and you have the reason why Wing carburetor throttle shafts are from time to time found to be twisted slightly, making getting a good idle and synchronization difficult. Be on the lookout for this. Don't force resined-up throttles open, and consider this cause when syncing is difficult.

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