NASA study that says lock washers do not work.
... there's at least one YouTube video showing nuts 'n' bolts vibrating loose with and without lock washers ...
This much I know from first-hand experience ... Having been using stainless since about 1979 or 1980, from a couple of years later, I was able to afford to change large quantities of standard plated bolts, screws and self-locking nuts (usually Cleveloc) to stainless steel bolts, screws and domed nuts. Early on, I lost a few domed nuts and sometimes the bolts, washers and components too. This was expensive, so I started fitting lock washers, usually what my usual supplier calls "Heavy Duty" - oblong-section wire rather than the more-common square-section. Also, around the same time, I paid more attention to the length of bolt/screw thread into/through nuts - as a rule-of-thumb I use the thread OD; e.g. a 5/16" bolt or screw has 5/16" thread length into/through the nut, a 7/16" bolt or screw has 7/16" thread length into/through the nut, etc. You know what ... I haven't lost a domed nut, bolt, screw or fastened component in a very, very long time ...
If the internet has a downside, it's that anyone can publish anything - right, wrong, well-researched, poorly-researched, biased, unbiased.
Internet search engines cannot make any of those distinctions, nor relevant or irrelevant; they simply return links that match keywords in a 'question'. At best, the internet is simply a tool, basically no different to a hammer, wrench, etc.; so the same applies - if you don't use a tool correctly, it won't give you the correct result. How do you know if a result is correct? Experience and judgement.
So, in many ways, I'm glad I did many things - stainless fasteners and other components, lock washers, DOT5 brake fluid, blah - Before Internet. Then, if something seemed like a good idea, I just tried it, rather than endlessly trawling the www and agonising over search engine returns. Now, with first-hand experience, I read stuff on the internet and think, "That isn't my experience". Then, if I'm that interested (e.g. lock washers work for me, why all the stainless on my bikes hasn't rotted them into heaps of corrosion on the garage floor), I can ask a question and use my "Experience and judgement" to sort out "right, well-researched, unbiased, relevant" from "wrong, poorly-researched, biased, irrelevant".
Couple of things to bear in mind here. Widely: NASA, ASME, Uncle Tom Cobbley An' All wouldn't design 4-stroke single- and 360-degree parallel twin-cylinder infernal confusion engine without a balancer shaft. But, lo-on-ng BI, engineers
"who just make things work" (to quote a highly-experienced engineer who posts on a few other Britbike-related sites) designed and built millions of the things, which conveyed similar millions of owners billions of miles. Speaking as someone who earned a crust designing and building computer systems for over two decades, beware the "expert" with a computer ...
More-narrowly: you're on this site because you're doing the same as everyone else here - keeping vibratory half-century-old motorcycles reliable for thousands of miles. If anyone else here is also
sending rockets into space, they're on different internet forums for that. With wide experience, it's easier to judge the relevance of sending rockets into space to keeping an old vehicle reliable.
should I use Loctite putting my 1970 Bonneville back together?
Define "Loctite"? If you look at the actual Loctite site
(as opposed to resellers'), there are a whole host of "Loctites". Ime, it'd be unwise to use Loctite Superglue?
Or even Loctite 263
of the "Threadlockers", which I suspect is what you mean by your question?
Fwiw, I've never used Loctite on any cycle-part fastener; generally lock washers work for me; the one place they don't regularly is on an aftermarket part I happen to use; there I use a Staytite (a particular type of all-metal self-locking nut) locked against a plain nut, which has worked for me for many years.
There are a few places in engines where the workshop manual recommends a particular Loctite "Threadlocker" type, and a few more where some people use Loctite 243
. Nevertheless, you're trying to keep a particular vibratory half-century-old motorcycle reliable, YMMV.
Finally here - neatly tying the two parts of your post together
- if you choose self-locking nuts instead of lock washers, bear in mind self-locking nuts wear out too, and they're a damn' sight more expensive to replace than lock washers.
Ime, the worst 'self-locking' nut type is Nyloc - I actually manged to wear out a handful in one afternoon fitting and adjusting an after-market part;
luckily, they were plated and I wasn't intending to use 'em anyway.
The rule-of-thumb for any self-locking nut is: if you can screw the nut fully
past the end of the bolt or screw with just your fingers, the nut's shagged.
Most of the original self-locking nuts on your bike were an all-metal type known as "Cleveloc"; the maker's still around and aiui still makes UNF.