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Aftermarket parts in the afterlife of Hondas…

Why can't they just make a perfect copy? A/m part on the left.
Why can't they just make a perfect copy? A/m part on the left.
Bill Silver

In recent years, those of us who are still wrenching on the 1960s Honda twins and singles sourcing NOS OEM parts has become increasingly difficult. Using eBay auctions, with sellers in Asian countries, have been a boon to those of us in America who are finding less and less inventories to pick from. Many sellers of vintage Honda parts have indicated a downturn in the amount of orders for the 1960s bikes, as the younger generations come up and seek out bikes from their youth; bikes from the 1970s-80s.

I have tapped into the resources of Retrobikes, ClassicHondaRestoration, Ohiocycle, Western Hills Honda, 4:1 and others who have been offering aftermarket parts to replace the withering supplies of OEM Honda parts. In some cases, these vendors have pooled their resources and had reproduction parts created for sale and then divided the costs and inventories among themselves, in order to contain the costs.

Usually, the replacement parts have been made to Honda specifications and work well in practice, but some products just cannot be recommended for use. A few years back, my friends Terry and Carole of Retrobikes, up in WA, were offering inexpensive D&K labeled gasket kits for the Honda 305cc twins, which seemed to be accurately made, dimensionally, however when engines were built with these new “non asbestos” gaskets, HUGE head gasket oil leaks erupted within moments of the first engine firing cycles. Ed Moore, my mentor and friend in the 250-305 engine building community experienced the same issues that I had seen; nearly instantaneous oil leaks as soon as the engine was run for the first time. Ed and I both contacted Retrobikes, who was one of the earliest customers of the D&K gasket sets. A few photos and samples of the failures yielded a rapid reply from Taiwan and new sets were shipped out with upgraded gasket material, which Retrobikes, in turn, shipped to all customers who had purchased the earlier types. Replacement gasket sets have been accurate and leak-proof, so far.

Honda 250-305cc Dreams used either Nippon-Denso or Kokusan ignition/charging system parts during the 1960s. N-D was the major contributor of many bikes, but you do see the K-brand on bikes, from time to time. Looking at eBay under “Dream ignition points” reveals quite a lot of the Kokusan-brand parts, but few N-D point sets. The two designs are totally different from each other, with N-D using a small adjuster screw that must be placed first before the contact set is installed. Kokusan parts just have a few small slots along the edges, where a flat blade screwdriver must be used to lever the contact set back and forth, so correct gaps can be achieved.

My personal peeve is with the “replacement” parts made by Daiichi in Japan. These are supposed to be direct replacements for the N-D point sets, but setting them side-by-side, reveals large variations in design and production of the parts. The only way to achieve both the correct point gap and specified ignition timing is to slot the backing plate another 10degrees, top and bottom. Otherwise, you are left with the backing plate fully rotated against the backing plate screws, while the point gap is just barely at .010-012”. New points have rubbing blocks with little high spots which wear off in the first one hundred miles or less, reducing the gap from the initial setting. Increasing the gap beyond about .012” will send the spark timing beyond the F mark initial timing and that takes the total spark advance past the II advancer marks on the rotor. There is no “work-around” for this problem other than to increase the slot lengths, as mentioned earlier. Thus, there can be NO recommendation for purchase and use of the N-D replacement ignition contacts which fit the Dreams.

Daiichi makes replacement parts for the factory N-D points on the CB/CL72-77s with Type 1 engines, which are a little more accurate and adjustable; however they should only be used as a last resort. You would think that a company with the resources to manufacture ignition point sets would make them more accurate then they have, plus test them on actual vehicles.

Back in the 1980-90s, a wholesale warehouse called “Dixie International” had made large purchases of OEM Honda parts and distributed a line of replacement parts, labeled “Superior” brand. Superior manufactured diverse parts like exhaust mufflers for Dreams and Super Hawks, ignition replacement parts for many vintage Honda models and even created chromed side covers for Honda fuel tanks of various sizes.

While the outer details of the Dream/CB mufflers were pretty accurately made, hoisting one up off the workbench left you with a definite feeling that there wasn’t a lot of metal inside these muffler shells, however. The end result was that the Superior-brand copies were 30-40% lighter in weight and had a tendency to rattle the inner baffles loose within a couple of hundred miles.

The fuel tank side panels were generally well-made, however they didn’t always install on the fuel tank mounting lugs easily and then the forward bolt hole might not line up just right. If you could get them installed on the fuel tank and fit the kneepads over the edges of the retainer lips, it can be hard to tell the difference between OEM and Superior brands.

A recent development arose when I purchased a set of D&K engine gaskets from an eBay seller in Japan who has them private-labeled on the packaging. They were ordered in advance of a repair job that I was anticipating doing within a few weeks. Delays pushed the start date back further; beyond the 30 days that eBay allows buyers to receive a refund on a purchase. When the bike came in for the top end gasket repairs, I was horrified to find that the gasket set was poorly manufactured requiring enlarging of numerous bolt holes and oiling passages. Several extra hours were spent reaming holes and trying various tricks to get the head gasket to square up with the cylinder bores and the bolt/oiling holes. Ultimately, enough effort was made to get the gasket to actually fit the cylinder block.

When I filed a complaint with the seller, he came back with the standard “I have sold hundreds of them with no complaints” instead of “Sorry you had a problem, tell me more about it.” I forwarded photos taken of the obvious defects of the gaskets, which were supposedly forwarded to the manufacturer for review and comments. My dispute case finally timed out, due to lack of response at the manufacturer level and the seller. So far, the bike has held up, but the additional time spent on making it fit cost me several hours of lost labor time.

Again, we have the situation where a company which has the capability to manufacture replacement parts with today’s technology at hand, still is unable to accurately create a workable part, then not take responsibility for the inaccuracies.

Honda put out bulletins to their dealers, even back into the 1960s warning dealers and mechanics NOT to use inferior aftermarket parts, often with good reason. Recently, a 1965 CL72 Honda Scrambler developed a large loss of oil out the breather tube, which normally indicates worn rings/cracked piston or other blow-by creators. Ironically, when the spark plugs were pulled, they were dry and normal looking which is not what you would expect to see with an engine having blow-by problems. The other condition which creates a lot of oil loss out of the breather tube is when the breather baffle plate is installed backwards, with the drain holes at the top, instead of at the bottom. This traps oil in the top cover and it is expelled at high rpms.

Removing the CL72 engine’s top cover revealed that a previous owner had used an aftermarket gasket for the breather plate, which had been installed correctly. However the gasket material had absorbed oil and it all turned into a congealed gooey substance which was trapping oil solids/vapors in the cover plate which were then pushed out the breather tube. With the old gasket removed and a new one installed, the breather plate was able to do its job, once again. Hard runs, at high rpms, did not push oil out the breather system afterwards.

Be aware that many of the gasket sets, made in the 1960s were created from asbestos-based materials and can be highly toxic when ground away into dust/chunks. Be sure to clean your work area well, after scraping gasket material from any vintage motorcycle, but use a broom and dustpan, NOT an air blower nozzle which will send fine particles into your workspace and into your lungs. Motorcycle mechanic work is fraught with dangers, especially chemical exposures from gaskets, clutch plates and brake shoes. Treat these items with care and dispose of the old material properly.

Whenever possible, use OEM parts, especially ones which have been manufactured within the past five years. You will be happy you did, even if they cost a little more money than the cheap aftermarket replacement parts.

Bill “MrHonda” Silver

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