A few years ago I had opportunity at someone's suggestion to read Julian Ryder's 1999 Honda's V-Force, subtitled Their four-stroke V4s on road and track. An enjoyable read, nicely illustrated and well-written, and containing many interesting observations and insights. It's rewardingly engaging.
I actually found a lot to like in the content covering the first-generation production bikes. I particularly like his description of Honda V4 engine power as "seamless'" and a resto on a V65 Magna I did a few years ago reminded me of how "electric motor" -like the power is. Very uniquely so. I did however stumble over one or two things Ryder said about the technical aspects of the early production bikes, especially that in Chapter 4.
VF500 Crankshaft Recall
Ryder doesn't mention that this was in fact a recall, meaning that it had serious safety implications. But for all that it was pretty limited in scope. It should be noted that the recall, which involved replacement of the whole engine, which you could do while the customer waited, was preemptive and more importantly, a customer perception issue primarily, as far as the United States was concerned. The actual fault was crankshaft flywheels that cracked under a certain unique condition, that of sustained top speed use. The crankshaft was quite minimalist, mass wise. Since there is nowhere that kind of riding could be done in the U.S. outside of the salt flats or a racetrack, it was almost academic in the U.S. Even Germany's autobaun isn't as wide open as many think. Anyway, it was a good move, but as I say, really perception control, PR if you will, in the U.S. The engines came inside wood crates with foam rubber balls in their intake and exhausy ports. I knew a tech who left in one of the balls and had it fly out on startup...
Oil Banjo Bolt
The oil banjo bolt thing borders on the apochraphal. I was there, first at the corporate office and later at the dealership, when these bikes were introduced and were afterward current models. The shaft drive (Sabre, Magna) and chain drive (Interceptor) bikes have different oil banjo bolts. The difference is the shaft drive bikes' bolt has a jet construction, something Honda also did on the early inline fours in the same area, the beginning of the oil path to the top end. Of course on 1st-gen V4s this path looks like a steel tube, whereas on the SOHC fours it's a drilled passageway in the cylinder casting and head casting. The V4 shaftie bolt is different because its oil feeds its unique part, the right angle drive, whereas the chain drive bike didn't have this unique oiling need, so its bolt was plain Jane, no jet construction at the end of the bolt. However, some wise guy noticed the difference between the two bolts and began spreading the misinformation that replacing the jetted bolt for the non-jetted (speaking strictly of shaftie V4s) was a good field fix for supposedly oil starved cams. However, oiling had nothing to do with the cam issues, and besides, lowering the oil pressure (which presumably would increase its flow) was by no means a good idea, and further and more importantly, was not sanctioned by American Honda. In fact we (I was there at AHM) categorically recommended against the modification, having learned about it early on.
V4 Design Runs Hot, Contributes to Cam Failures
I don't believe Honda V4 engines run excessively hot, and even more clearly, rear cams did not fail before front ones, and even if heat were a factor, you would have to bring in oil breakdown to even start to make a case for this. No one has ever proved even theoretically let alone statistically that heat is the primary cause of these cam failures. Further, there were any number of bikes whose engines were known serious heat makers, on the order of 350 deg F oil temps, which anyone will tell you heavily taxes petroleum based engine lubricants and yet these engines did not experience cam failures. The CBX is a prime example.
Bad Cam Chain Tensioners as a Cause of Cam Failures
This is actually funny. How could the two be related? Not only that, but only the very early tensioners went bad prematurely, and then only by backing off their tension to the point that the very massive link plate cam chain made its presence known audibly. A very minor thing, really. The updated tensioners, which I was already installing as a dealer tech in 1983, simply had a slightly thicker shaft. You know how they worked, don't you? Think of a screen door closer. Remember that you could prop the screen door open temporarily by sliding a tiny plate down the full length of the closer's shaft? Then when you wanted the closer to work normally again, you slid the little plate all the way the other way. The V4 cam chain tensioner worked just like that. As the chain wore, a shaft slid through a plate that was cocked to grip the shaft. During installation or removal, the tech merely uncocked the plate to retract the shaft. The updated tensioner was exactly the same except it had a thicker shaft, I suppose to offer more surface area to the gripping plate.
Final Solution The Special Valve Adjustment Tool
Let's cut to the chase. Honda themselves changed their mind about this tool, as Ryder dutifully mentions. The whole cam tool thing was corporate coverup, that is, a way to blame someone, and that someone was their dealers (which OEMs have a track record of doing, by the way. There were some abnormally loose cam bearings in 1982. Techs approached those unique few bikes with a totally different solution, hand-fitting sanded down bearings, and Honda later produced a special kit. I did this myself. There is no relation between loose cam bearings, which appeared on only a few hundred bikes at most, with cam failures that went on for the whole series of 1st gen 750s and 1100s. Related to this, I suspect Ryder borrowed some ideas from my website, which existed at least 7 years before his book did, when he speaks of this tool. The information is in a very obscure dealer bulletin (not even a bulletin but a mechanic's newsletter that no one reads) available only to authorized dealers. In any event, he seems to agree with me about the tool being bogus specifically because the bulletin that accompanied the tool's release specifiies a change to higher engine idles, on all models, something that an experienced technician would associate as I did with tighter than normal valve clearances.
Honda's Replacement of the Early Production Run 1982 Cams and Bearings
There never was a program for this. We (I was at the factory handing parts out, that was my job) learned of Japan's -330 (I think that's the right number, see my article) bearings and -990 cams and were suggesting their use to dealers and occasionally authorizing this under warranty auspices, but there was no program, and very very few wholesale replacements. And again, it was for only the first couple hundred 82 models, to bring them to the same spec as all the later ones were by then and would be later. In other words, normal 0.003" clearance instead of the 0.005-0.006" that was common on some very early units out of the chute. Please note that 0.003" is still quite loose for a cam, but every manufacturer before and since has worked to the same spec. The DOHC fours prior to the V4, the CBRs after. Cam bearing clearance has nothing to do with cam failure, only in some cases engine noise.
I realize this critique may sound harsh and self-serving, but ss good as Julian Ryder's book is, I doubt he was there when ths stuff happened, judging by these mistakes. A good read nonetheless, and a book well worth getting, from the historical perspective, excellent writing, and technical interest.
Early Honda V4 history
Fallacies about first-generation V4s found on the web
Early Honda V4 cams -- what really happened