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Powersports Media
Part 1
Common Internet fallacies
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Motorcycle user forums are not good sources of wisdom; none of the real issues of maintaining a motorcycle can be found there. Instead, they deal in the trivial, the faddish, the apocryphal, the vacuous, and do so with a rabid, almost religious devotion to extemporaneous ideas. There are of course seemingly very talented folks on forums, very creative custom motorcycle builders and modifiers. Astonishingly adept, many if them, at restoring and fabricating. Yet strangely, these same folks, most of whom have never made a living maintaining these same motorcycles, have received very scanty technical training, and have never been refined in the fire of a retail repair environment, these folks don't even know how to check their oil or lube their chain or replace their fork seals. And they won't for a minute allow career mechanics to tell them. Here is just a small sample of the vast world of misinformstion found on motorcycle user forums.
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Carburetors
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Item: The supposed evils of ethanol-laced gasoline
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This may be the biggest fallacy on the Internet. Ethanol is not the evil scourge the powersports media says it is. This fallacy is often described in terms corrosion, loss of performance, chemical damage of rubber components, and reduced fuel shelf life. The motorcycle industry did in fact make some very corrosion-prone carburetors. Despite this, no motorcycle, ATV, scooter, personal watercraft, snowmobile, or recreational vehicle's carburetor is more than slightly more at risk for corrosion due to ethanol than before there was ethanol, and post-1980 carbs have never been vulnerable. Those who perpetuate the ethanol myth don't understand the technology, don't know the history, and aren't aware of the forces at work in the powersports industry. More...
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Item: The over-valuing of carburetor felt seals
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There is a pervasive but false notion that your carburetor's throttle shaft seals contribute to performance issues. Actually, they don't. These felt rings are dust seals only, not vacuum seals. The sole job of these seals is to slow the entry of abrasive dirt that would hasten the wear of the brass bushings the throttle shafts are mounted in. That's it. They guard the bushings, not the vacuum. Instead of all this hand-wringing over supposed effects the felt seals have on performance, it is much wiser to go after the things that really do hurt engine efficiency. More...
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Item: Float level
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There is a tenacious belief among motorcycle riders that the height of the carburetor's float is somehow linked to float bowl overflow. In other words, that a float's height is the carb's first defense against carburetor flooding. This is wrong. Float level equals mixture control. Nothing else. If you experience carburetor overflow, fix the problem. Don't try to strangle the carb dry by altering float level. Shutting off your house's water main isn't how you fix leaky plumbing. More...
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Item: Float valves
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Though they're beginning to change, many forums and other Internet sources unabashedly endorse carburetor rebuild kits. However, no professional carburetor rebuilder uses rebuild kits. Because they're junk. The crappy aftermarket valves cost $5 and the good OEM ones more than twelve times as much. There's a good reason. More...
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Item: The less air test
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Internet "experts" often promote such troubleshooting techniques as spraying aerosols around the intake manifolds, not realizing or even willing to believe that maybe that is not the way professional mechanics do things. In fact it is not. The pro way is called the less air test and it really works. Not only that, it is the professional way to not only discover vacuum leaks, but more importantly, to narrow down troubleshooting possiblities between mechanical, intake, and ignition, and it even helps with rejetting carburetors. More...
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Item: Honda's idle drop procedure
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User forums propagate a technique that has little to do with proper tuning. It's one more instance of the powersports media latching onto the trivial at the cost of the vital. Honda's idle drop procedure is not part of correct idle mixture screw adjustment. The idle drop procedure is uniquely Honda's. It originated on their early cars. Call it whatever you like, it is not tuning. More...
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Item: Honda CV carb slide holes
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It is often stated that when removing a Dynojet kit--which CBX carb rebuilders do fairly often--the slides need to be replaced because of the hokes drilled in them. It's not true and shows a lack of awareness of what those holes do. What Dynojet was trying to do with the slide hole enlargement was...more...
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Item: Deadly carb rebuilding practices
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There is a ton of this out there. But let's take just three items: stroking throttles, burnishing float valve seats, and using pliers on float pivot pins. Stroking throttles is very bad. If you look closely at the throttle plate of a modern CV carburetor you'll notice the plate's edge is not machined at 90 degrees, it is rather at an oblique angle; it is in fact a knife edge. This angle accomodates the angle that the plate is itself mounted in the carburetor, so that the edge of the throttle plate seals perfectly against the carburetor body. More...
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Item: Running carbs dry
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The advice to run carbs dry is showing up more and more on vintage Honda forums as a technique promoted to avoid fuel varnish. Unfortunately, though it sounds intuitive, it does not work. Running the vintage Honda engine until it dies will not eliminate all the fuel. See my video to learn why.
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Item: Vapor honing as a substitute for cleaning carburetors
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Wet blasting, or as it's known, vapor honing, is a very popular carburetor repair technique. I use it myself. But it is possible to misuse wet blasting. When it is used as a cleaning procedure, that is bad practice. It does not clean, it texturizes. More... ************
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Engines
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Item: Refacing Honda valves
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In our grandfathers' day valve recession was corrected by removing the valve from the engine and grinding its ridge on a special machine that had a super-smooth grinding wheel. This was called "refacing". But 70s and 80s vintage Hondas are unique. Many mechanics persist...more...
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Item: Head gasket leaks
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One forum is saying that special parts and engine modification are needed to make vintage Honda head gaskets not leak. This is not so. Careful prep of the mating surfaces and the use of factory quality gaskets makes all the difference. More...
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Item: Forged versus cast pistons
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It's true that most aftermarket pistons are forged, but that is due more to manufacturing realities than to product superiority. Performance engine builders prefer the freedom forged pistons offer of excess material on the crown with which to customize the piston top to their needs, something that cannot be done with minimalist cast pistons. More...
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Item: Gasket sealers
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Much of the powersports Internet endorses the use of silicone sealer on motorcycle engines. This is really a bad idea. There are specially-designed sealers for that purpose. More...
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Item: Cam holder bolts
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The cam holder bolt torque specs in many OEM manuals are incorrect, and Kawasaki, Honda and Yamaha have documented the issue. Using these specs results in over-torquing leading to bolt failure, and worse, distortion of the cam holder, which has resulted in cam seizure. More...
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Item: Engine break-in
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There is no such thing as "break-in" in the sense that it is used online. Due to the high precision of manufacture and assembly inherent in Honda top end parts, the cylinder compression of a properly rebuilt Honda engine will be the highest it will ever be minutes after startup, before it even leaves the shop. It will not increase with miles. More...
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Item: Early Honda V4 camshafts
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A lot has been said on the Internet about the failure of first-gen Honda V4 cam failures. It is misleading. Lubrication has nothing to do with it. At one time there were a number of different oil hose kits available. These kits exist solely due to...more...
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Item: Porting
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There are two completely different worlds when it comes to cylinder head porting. It's not at all what most folks think. The knowledgeable person concentrates on radii and contours, not volumes. More...
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Item: Cylinder honing
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One thing almost every forum's engine repair thread includes is the mention of honing in-service cylinders. Likely the notion of honing in-service cylinders originated when engines were basically solid cast iron and had low-tech pistons, the combination requiring clearances of several thousandths of an inch. During this same era, piston rings weren't the best either and...more...
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Item: Valve adjustment
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Something career mechanics have known seemingly for eons is that loose valve clearances are better than tight ones. Loosening valve clearances, though no substitute for the needed valve job, often restores a measure of compression and results in...more...
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Electrical
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Item: Supposed defective Honda charging systems
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Honda's 70s sohc fours come in for a lot of criticism on forums for their charging systems being "inadequate". These critics have somehow found faults that have been unknown to Honda riders for more than fifty years. Honda's electromagnet-based charging systems don't exceed an equilibrium point until 1300 rpm, which means they don't charge at an idle. More...
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Item: Ignition coil fallacies
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The Internet is really confused about ignition coils. Visitors to user forums are just as mixed up. Rhetoric is more common than logic in ignition system descriptions. What is missed in the discussion of coil primary resistances is the fact that...more...
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Item: The Bosch relay mod
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Forums encourage fitting the classic and simply Bosch style horn type relay in vintage Honda ignition and headlight circuits. This is promoted as a way to increase the performance of these circuits by way of increasing the voltage to them. While effective...more...
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Item: The stick coil craze
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Many forums advocate the retrofitting of "stick coils"--that is, coil over plug ignition coils--to vintage motorcycles. Can they be thinking that many of the modern engines they're found on are more powerful because of presumably higher voltage sparks? They're not. Stick coils are actually the lowest output ignition coils ever. More...
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Item: Electrical crimps
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General
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Item: Drum brake actuating arms
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All over powersports media the telltale oddly-angled rear drum brake actuating arm indicating dangerous arm "recamming" is evident. Many folks in the 70s discovered the advantage of splining the arm backward a few degrees to gain a few extra miles of brake shoe wear. There is a really bad practice and a serious problem. More...
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Item: The VIN system
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Folks on forums call everything a VIN (vehicle identification number), as if it were just another name for a serial number, a kind of shorthand or nickname. But a serial number and a VIN are very different animals. The serial number, which merely identified a vehicle within its series, reigned until the 1981 model year, when everything changed. More...
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Item: The decel wobble
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Vintage Hondas can develop a head shake when decelerating rapidly from 60 mph, especially when you take your throttle hand off the bars to check your helmet catch. The decel wobble is not normal. The cause of the classic decel wobble is...More...
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Item: Sanding brake pads to eliminate squeal
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It does you no good to sand a brake pad or brake shoe. Yet so many seem to think it should. It's amazing how long this fallacy has hung on. Brake squeal is caused by pad or shoe vibration. That is why later disc brake pads are nestled in place with all sorts of leaf springs jamming them against the caliper body. But vintage brakes didn't have that. What some vintage brakes did have however were gaskets. They work well. See my vintage Honda brakes how-to booklet.
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Item: Allen (socket head) screws
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How many times have you seen Internet "experts" recommend replacing Phillips screws with Allen head screws? What you need to know is this simply replaces one problem for an even greater one. You have merely traded unprofessional handling of the heads of the screws with unprofessional treatment of the screws' threads. You've not gained anything. You've actually made things worse. More...
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Getting it backward
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Here is a brief list of things Internet motorcycle "authorities" get wrong, and not only wrong but actually completely backward.
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Most of powersports media encourages folks to make their bikes' valve clearances tight but their pistons loose. The reality is the exact opposite. Valve clearances need to be loose and pistons tight.
The powersports industry has done its damnest to convince riders that their biggest carburetion worry is what is in pump gas. The opposite is true. As already mentioned, what is missing from today's gas is the real worry, not what's in it.
Aftermarket powersports retailers want everyone to think that changes to the exhaust make huge differences and changes to the intake virtually none. This is backward. Intake modifications upset carburetion ten times as much as do exhaust changes.
Many voices in powersports insist that glycol brake fluid is better than silicone brake fluid. This is shamefully false. Silicone brake fluid is superior to glycol fluid in virtually every measurable way.
Forums propagate the ethic that having cylinder compression consistent across cylinders trumps having compression nominally high. This is ridiculous and backward. Having all four cylinders hovering around 110 psi will do you very little good. The bike will run like a turd. Cylinders that range from 130 to 150 result in much better performance, despite the variation.
The wannabe mechanics in this industry seem to believe that moderately increased cylinder compression results in the need for more fuel, i.e. it leans out carburetion. The opposite is true. The moderate compression increases resulting from rebored cylinders improve combustion, thus making fueling more efficient, thus carburetion effectively richer.
Forum "experts" make much of Honda's presumably overly optimistic cylinder compression values, calling them unrealistic and impossible to achieve and encourage capitulation. This is not only backward, inasmuch as compression is the single most important aspect of performance, it is stupid. What they should be talking about instead is the correct tools and methodology for measuring compression, where the lost compression has gone, and how to get it back.
Internet sources like to disrespect everything OEM: specifications, dealer mechanics, procedures, parts quality, etc. What they should do is first, recognize they haven't even begun to approach the excellence of that which they mock--they are nowhere near OEM level--and second, become students of that which they are so woefully ignorant of. It would definitely improve their outlook.
Those on forums who have electrical engineering backgrounds apparently believe their education trumps the lifelong, specific-applications observations of career mechanics. Not so. Not a one of them understands the tension, the gap, between how a part is designed and how it actually works, something that is second nature to the professional mechanic. Again, they have it backward.
All of the Internet vintage Honda voices think nothing of slathering any and all gaskets with unnecessary sealers, but inexplicably neglect the one gasket that actually requires sealer. Backward again.
Most forums promote valve lapping as if it were a normal part--seemingly the only part--of a valve job and completely ignore what a valve job is. Very backward. No one who gives it ten minutes thought will ever lap a valve and it is never part of--let alone the predominant part of--a valve job.
Those outside the industry portray carburetor synchronization as some rare, very occasional, even isolated thing. The reverse is true. Professional mechanics know the reality that synchronization is a task requiring frequency and is very often the final step in all sorts of maintenance scenarios.
So much of the online powersports media talks about carburetion as being all about fuel and ignore the air aspect. This is backward. Carburetors are air instruments, not fuel instruments. What is compression? Air. What is combustion? Air. What is throttle response? Air. What is carburetor synchronization? Air. What does the throttle control? Air. What goes into the engine and then leaves it? Air. Air is the engine's medium. The fuel's job is to manipulate that air, the carburetor's is to manage that. Air does all the work.
The powersports media also likes to tout the forged engine piston as obviously superior to the cast piston. As with so much that they say, this too is backward. As mentioned above, most riders don't need the forged piston's increased detonation resistance and ability to be custom shaped and would instead rather have the cast piston's better sealing, quieter operation and longer life.
Forums are almost defined by their insistent rhetoric concerning ethanol, as if it is the most dire issue regarding the carburetor today. It is not. Far from it. Ethonal is not only the least of our worries, it's actually a non issue, as reported previously. The real carburetor catastrophy is the fact that as of 2020, Honda has finally run out of original equipment carburetor internal metering parts for their 1970s inline fours, specifically the jet needle and needle jet sets. This is no small occurence.
So many restorers, careful and insightful observation will show, focus on the appearance. Powdercoat, polish, plating and presentation. That's their stock in trade. But motorcycles are so essential. That is, so minimalist and basic and direct, mechanically, that they demand just the reverse--the beauty and perfection and completeness that comes out of mechanical rightness. And that is much more work.
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Getting motorcycle maintenance advice on the Internet is like putting the Coca-Cola company in charge of your healthcare.
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Last updated January 2025
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© 1996-2025 Mike Nixon
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