With all of the effort that's being put into these projects by all of these different people, somebody ought to look into having patterns collected for making reproduction parts that are correct to the type.
It would certainly be a special challenge for say, the folks who are making reproduction Vincents or MV Agusta 350 fours and the like, if they could make a proper sand-cast replica that all of the experts couldn't tell from an original. I know, it would take a hell of a lot of the mystique out of the whole thing, a reproduction part wouldn't have the same "soul" or whatever. Maybe they could have a small maker's stamp just so that people would know the difference, so that when they're doing their whole "touch-stone" thing and connecting with the past through this amazing time-machine of a motorcycle, they would know what's actually transporting them back in time, and what's just giving them a cool retro vibe. But yeah, at the very least, the bolts and screws and stuff, ought to have some reproductions made.
Because the real goal here is that ALL of the original bikes be put back to original condition, then ridden hard and put away wet for thirty-forty years, and re-built all over again! To THAT end, it behooves one to take decisive action. Because let's face it, it will be hard to find even the most anal-retentive kids of the next generation who'd be motivated enough to even read through some of these threads, unless it relates somehow to what they're trying to do with their '05 CBR restorations, so why not make it a little more "user friendly" for the next generation of Sand-cast restorers? You know damn well, it would be extremely lucky if all of the bikes are restored in the next fifty years, all all the more less likely people would feel inclined towards it in the first place, come ten or twenty years down the road. So, the more of these parts that have been oh so lovingly and carefully measured and restored and compared for finish quality etc, that they be reproduced in as authentic a practice as possible.
Perhaps reproduction dies for stamping the heads of these bolts could be fashioned? I dunno WHO, but certainly NOW IF EVER would be the time when a company would feel economically motivated. I doubt very very much that Honda itself would EVER feel the need to help out the restorators out there, they have such a crappy record with helping people with spare parts in the first place.
In my own experience, I had a '69 CB100 when I was sixteen, back in 1990, and when I asked at the parts counter for just a peep at the parts fiche and for help with getting parts for it, I was lied to point blank about the whole situation, and I think their reasons for doing such was that an inherent conflict of interest exists when dealerships are responsible for the warantee work and all of that rot, let alone keeping vintage machines on the road. The primary motivation for a dealership is selling more new bikes. The parts and maintenance dept should be a separate entity, taken on by the parent company itself, not subordinated to the local franchise dealerships. As such, the whole business model has been screwed from the get-go, long before these "early" bikes were even made. I've heard some real nightmare stories about dealerships in the early-to mid sixties, where Honda left them with ridiculous recalls to deal with, and more work being done in the local shop than ever went into the bikes on the assembly line itself.
But right about NOW would be the best financial incentive, and it would make life easier for those folks who'd ALSO like to restore their bikes but who may not be quite as anal as you are.
So, what I'm thinking is, maybe some of these very rare and special parts that each individual owner-restorer has his hands on, whether they be rubber damper blocks or gears from the transmission, or hubs or bolts or ... whatever, could be cast in a dental-silicone or whatever it's called, just a good solid supported mould, maybe a chunk of plaster or even a ceramic mug to keep the whole project time to a minimum, anything size appropriately for the part, then the wax or silicone #$%*, supported by the hard object be it a mug or a plate or whatever, and then somebody ... NOT ME ha ha, could collect some of this #$%* together, hell I'd talk to some kind of specialy fasteners manufacturer, or even somebody who's a big player on the sand-cast parts supply end of things, so that those most rare and unusual parts could be made rather than just a substitution of later edition parts be they die-cast or late era sand-cast parts. There are already people out there making reproductions of the magnesium twin-leading shoe hub for the CR750, and the dual disc front hub was put into reproduction by aftermarket people a long long time ago (Though I sure don't understand why people wouldn't just use the gold-wing hub for that application....) so, despite the high cost of the CR rear drum, given the different materials I don't think it would have to be outrageously priced.
Then, perhaps even using mostly the same moulds with perhaps a different center insert, as was probably the case with Honda's production casting of long ago, the no hole and two hole and four hole hubs could be available to all, and what with all of the information gathered then people would know, or have some good indication, whether and which of these hub types was appropriate. I mean, IF they wanted to do up an authentic reproduction. I'm sure it would piss off the guys who've bought up all of the NOS stuff. Some of them invested in buying up every last NOS part available more than ten or fifteen years ago, but hey I'm sure they've made their investment back by now! Ha ha. Really though, there's stuff even THEY can't help you with. I'm sure that if it was a re-call part, unless a shop was truly neglectful of their bottom line or made a mistake, or an employee raided the trash bins, that none of that #$%* is even AROUND anymore whether in the stocks of the NOS specialists or the Honda shops they cleaned out years ago. It doesn't seem like Honda's sueing any of the people making reproduction Cub parts over in Asia. Hell, I'd bet that some of THOSE guys would be just the people you'd wanna talk to about making this stuff.
But the important thing, is that whether or not anything like that would ever be possible, hinges on just how anal-retentive you get with these original parts. And I don't think anybody on the whole sand-cast scene would make fun of you for going even further than you've already done. You know what they say, you can polish something, you can restore it, etc. But you can't put it back to original. The patina is one thing on a coin and another on a bike part, yeah I realize that. But I'm sure that something could be gleaned about the finish processes by some kinda chemist lab, forensics lab, etc. Maybe if somebody ever murders anybody else over sand-cast parts ... somebody famous, hopefully a case with some racial component so that the media gets sucked into it like another whole OJ mind-#$%*, THEN the most extensive forensic work would be done on these things. Of course, most of it would be bull-#$%*. Ha ha. But still, if there's somebody could take a look at some of those parts BEFORE you run a tap and wire brush all over the things, maybe take some micro-macro photos, some sampled flakes of zinc or chrome, then the best understanding of the correct finishes at different phazes of production could be understood.
That's the type of thing that's being done in the collectors' fire-arms side of things, and most of those lugers don't hold a candle to these bikes so far as value right now. Fact is, a lot of fire-arms restorators or evaluators know a heck of a lot about metal finishing processes, especially obsolete stuff. Not too sure whether there's much known about the stuff from this period of history, I'm sure they know a lot more about 1930s or'40s Japan, than the 1960s....
It also seems like the big problem with the sand-cast scene is a lack of communication between western collectors/hobbyists/restorators and Honda itself, or even the former employees of Honda's manufacturing plants. You might recall the whole "controversy" about vaccuum die casting vs sand casting vs gravity die casting etc etc. That was settled, well for SOME of us I suppose, by a conversation with a former casting line employee. Or was it somebody who worked next to the casting line building? In any case, the whole Western scene seems too preoccupied with the likes of Dick Mann or Freddie Spencer (I'm a DOHC guy, actually. My interest in the sand-cast is for the sand-cast tribute DOHC build I'm working on. Sort of like a "Dream-DOHC", in more than one sense of the word....) than they wonder who the first guys to ride the bike were, on the secret factory test tracks. But I'm sure that you sand-cast nuts, like me, are a lot more curious about THOSE guys, than you care about the whole marketing side of things, which is what the early competition track riders were doing. Marketing. 'Cause the development was already DONE. Right?
Just my two cents.
Kudos on your exhaustive efforts for these bikes. Your spread-sheets seem like a fantastic resource. I only suggest that - The next opportunity you have to measure some rare, odd, original parts? Go for as complete a "measurement" of them, be it chemical analysis or even just sampling for later analysis, (From what I gather, some Zinc plating type processes were proprietary secrets?) down to a good detailed bolt-head moulding using a good quality material. They use that dental silicone crap to replicate the labia or fore-skins of porn-stars for the boutique sex toys people seem to buy record numbers of. I only mention it, 'cause that's the first place I ever heard of some of these materials. Ha ha. When my ex-wife worked in a love-shop when we were in college. Damn, I could tell some stories! Ha ha. But yeah, from what I gather they're very dimensionally stable, and they pick up an incredible degree of detail. A lot of the bodywork parts seem to be defined by the number of holes or this or that impression, like the two dent vs four dent undersides of gas tanks. Well, it wouldn't surprise me if a selection of gas tanks were measured with ... either one of those ruby-sensor deals, or maybe some kind of lazer or x-ray photography technique, then there might appear to be different versions or shapes of say, side covers or air-cleaners or gas-tanks, fenders etc, that are not immediately apparent to the naked eye, or the untrained eye. There are plenty enough of these bikes constructed side by side, as in your case where you've got three or four bikes for comparison. But seldom are they consecutive serial numbers, or even from the same series sub-unit, so how then do we know for sure what's out there that could be radically different? Just a few guys out there, like yourself, pouring over photographs and fondling every part or bike that you can lay hands on. The more accurate numerical data collected, such as your spread-sheets, the closer to perfection, the closer to a person being about to pop on the scene with "I just found # 34XX in my uncle's basement. Is this a sand-cast?" or even "Is this a CB750?" ha ha, and they could just connect with the right people and be able to obtain pattern reproductions of every correct part they'd need to put the bike back to as-new condition. Maybe with a couple dozen secret silver-smith type stamps on the new parts.
Anyway, I'm talking around in circles. Just high. Sorry.
Oh, and by the way, by far the best thing I gleaned from this thread was, in addition to your advice about pre-plating-preparation, the stuff about the home-made welding rods. I've been looking at modifying DOHC parts, (rear-set plates, valve covers capping off tach drives, etc etc) and was unsure which aluminum welding rod to use and how to determine which to use for which application. Your info hit the nail on the head. Though it's likely Honda changed their alloy formulae over that thirteen-fifteen year period, yours is a good method of determining like-materials.
Again, kudos.
-S.
