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Maybe it's not even reasonable to discuss the following on Britbike (or anywhere else, for that matter), since the posts of relatively few people here deal with issues beyond swapping broken items with replacement ones, or sending components to specialists to repair for them. As an indication, out of the ~60k threads, only a dozen (~0.2%) that weren't started by me mention the word 'Sunnen'.

After watching several hours of automotive machining videos on Youtube (typically not all the way through; just until I saw an example of advice that made me cringe) on installing and cutting valve seats, installing valve guides, honing cylinders, etc., I didn't find a single one that didn't have at least one significant error. By that, I mean an error that would have an effect on the function or lifetime. For example, someone deliberately bending the cutter sideways against the pilot to cut a portion of the seat that the cutter hadn't hit (because it wasn't Concentric with the guide), making a new seat from relatively soft steel, using an incorrect interference fit for a new seat, determining the "clearance" of the valve in the guide based on how much it rocked back and forth, etc.

Turning to books, most motorcycle "restoration" books basically just describe taking parts off a bike, cleaning or replacing them, and bolting them back on. Unfortunately, even a 250-page book is severely limited in the level of detail possible. Despite the 247-page length of Radco's 'The Vintage Motorcyclists' Workshop', its Chapter 3 "Engine Work: The Top Half" is only 34 pages long. Contrast this with a book from the automobile world, John Edwards' 494-page 'Sunnen's Complete Cylinder Head and Engine Rebuilding Handbook', which covers the same subject matter, but at a depth requiring over fourteen times more pages.

In an offline discussion with Shane in Oz about this I mentioned it was impossible to know if my observation about Youtube means many automotive machinists don't even know proper procedures, or if only "bad" machinists make Youtube videos. Shane responded that I was looking at those videos from the point of view of a precision machinist not a motorcycle mechanic. Hmm, perhaps so.

Finally getting to the point, the acceptable quality of restorations in 1976 when Jeff Clew wrote his restoration book was considerably lower than when Radco wrote his just ten years later, and since then another 35 years have passed. Certainly, the acceptable level of cosmetic restorations has continued to increase over that time, but what about the mechanical aspects of restorations and rebuilds? Given that internal combustion engines are very tolerant of wear and abuse, so that rebuilders can "get away with" being quite sloppy when working on them, how should someone working on old bikes look at this? An aftermarket bush pressed into place might work OK as-is, but the only way to know if the resulting clearance meets the original published specs and it won't fail prematurely is with a precision measurement instrument. And the only way to deal with it if it doesn't is with a hone. However, are such things, out of sight, out of mind? Is time spent on the mechanical internals, beyond getting them "good enough," time wasted?

Beyond the pleasure that doing such precision mechanical work might bring, in monetary terms are you (me) wasting your (our) time? Are people who buy restored old British motorcycles today unlikely to put enough miles on them to reveal shortcomings in the mechanical work? Would someone pay any sort of premium at all to buy a bike with documentation showing details of the mechanical work, or is chrome and powder paint all that really matters? Does the average buyer of an old British motorcycle (as opposed to the average Youtube video maker) know enough, or care enough, about the mechanical aspects to even judge the quality of, say, someone else's work to install new guides and seats?

Basically, I'm hoping for an informed discussion of questions like these with people who do more than bolt parts together, which would mean people who at least own a lathe and mill. However, as I said at the start, it doesn't seem very many people on Britbike fall into that category so this could be a very short thread.

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If I want to know how to apply a new technique to repairing or making a part on my mill or lathe I use YouTube but only experts in lathe or mill. Never look at bike mechanics working with machinery as they are not experts.

So first go to guy

Joe Pieczynski

https://m.youtube.com/channel/UCpp6lgdc_XO_FZYJppaFa5w/featured

Maybe that's because I worked in automotive manufacturing for 35 years as a qualified engineer even though never as an engineer. I never applied my qualification directly but knew enough to know [***] at 100 paces.

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It sounds to me like you are looking for feedback from machinists, as you seem to group anyone who doesn't own a lathe or mill with those that simply "bolt parts together". I think there is a wide range of skills that span much more than those two groups. For example, I've taken motor parts to guys who have been doing this work professionally for longer than I've been alive (and I'm not that young) and most of them sent parts out to professionals. Not your typical "bolt parts together" type of guys, nonetheless

Originally Posted by Magnetoman
Are people who buy restored old British motorcycles today unlikely to put enough miles on them to reveal shortcomings in the mechanical work?
I think this plays a big part in it. At, say, 1000 miles ridden per year, my BSA engine could blow itself to pieces at 20k miles (rather than the expected 25k miles wink ) but that puts it at 20 years out.

Originally Posted by Magnetoman
Would someone pay any sort of premium at all to buy a bike with documentation showing details of the mechanical work
I doubt it, and here's why:
this would then assume that anyone who doesn't provide this documentation is a hack. Or, any documentation you're not able to provide indicates you're trying to hide something. That's 100% not the case so anyone who's providing the documentation is patting themselves on the back but, unless they're linking some type of warranty to this documentation, it's going in the file without spending too long trying to understand what it means.

I personally think more important than knowing how to do your own work is knowing when not to do it and send the parts out to craftsmen who will do it correctly. It's too easy to watch Youtube and think yourself an expert. We all have our strong and weak points and we all make mistakes. What differentiates the true experts is that they realize they made a mistake where a novice won't.

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Originally Posted by MarcB
you seem to group anyone who doesn't own a lathe or mill with those that simply "bolt parts together".
My original post already was too long, but it was too short to properly qualify all statements. But, I don't see how anyone could believe I simply lump people into just those two categories.

Originally Posted by MarcB
this would then assume that ... anyone who's providing the documentation is patting themselves on the back
No, you've made an incorrect inference. It's common practice for a mechanic to provide copies of receipts, or an itemized list of out-of-pocket expenses, along with their bill for labor. It's not patting themselves on the back to provide documentation for the $20 to buy a valve guide, so why would it be for providing documentation showing how they installed that guide?

Originally Posted by MarcB
send the parts out to craftsmen who will do it correctly.
That's certainly a fine approach, but it gets back to one of the questions I raised. How do most people know someone is a craftsman, and how do they know they will do it correctly? Just because someone has been doing a job for many years doesn't mean they might not be doing it the same obsolete or incorrect way they did it at the start of their career.

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One example of the perils of sending things out to craftsmen happened to a friend of mine, whose magneto had 'packed up'. He sent it off, had it 'rewound', which is what the expert said it needed, only to have it pack up again within 300 miles. My friend was so trusting that he was about to send it back to the same guy until I, and a number of others, staged an intervention and persuaded him to send it to someone who really knew what he was doing.

I have a Phil Pearson crank that I am soon to install into two new John Cronshaw Gold Star crankcases. I know John Cronshaw's reputation from other friends, one of whom built a Gold Star trials bike around a Cronshaw engine. Before he retired, Phil Pearson was one of the best-known BSA engineer/machinists in the world. At the bottom of the engineering pile is me, who will be bolting it all together. If I don't screw up too badly, I'm hoping that the premium I paid for the work of these renowned experts will get me out on the road.

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Originally Posted by Magnetoman
Originally Posted by MarcB
send the parts out to craftsmen who will do it correctly.
........... How do most people know someone is a craftsman, and how do they know they will do it correctly? ........
Oh boy oh boy, is this a problem. We are down to two machine shops in our town. Neither one is full service ie crank grinds, line honing or line boring or even hot tanking. I have to send some jobs 60 miles away and others even farther. A recent BSA A10 crank regrind cost me $350.00. I do almost all of my own work and know enough to recognize acceptable work. I have literally taken my mikes with me to pick up machine work from well known "specialists" only to find incorrect (undersize) journal dimensions on a reground crank.

So IMO, the only way you can know is by your own track record and relationship with the particular specialist. But even that is no guarantee. I've been taking stuff to some of the same guys for years and frankly, I have occasionally just eaten substandard work in order to preserve the relationship. And the fact is, even the best guy can have a day when something didn't go right.

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I’m logged in here after browsing Sunnen honing machines on eBay…

I’m a machinist…

I own John Edwards textbook, and have had him do work for me (RIP)…

YouTube is spilling over with people needing attention and affirmation. My opinion is that the folks that know how like to guard their knowledge, or are too busy to make online tutorials.

Finally, it’s frustrating to participate when sound advice is drowned out by the peanut gallery regurgitating something they read elsewhere on the internet (really bad on the Facebook groups) or the same peanut gallery sharing pictures of their bike even though it has zero relevance to the discussion (also really bad on Facebook).

It can be horribly time consuming or expensive to make certain repairs correctly. It’s far easier to refinish something to look nice and leave the finer points of the mechanicals out of sight, out of mind.

Chris

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Originally Posted by Magnetoman
the posts of relatively few people here deal with issues beyond swapping broken items with replacement ones, or sending components to specialists to repair for them..
Motorcyclists, mechanics, machinists and precision machinists seem to form a Venn diagram with diminishing degree of overlap. A lot of motorcyclists are mechanics (trained or otherwise), far fewer are machinists, and very few machinists are precision machinists, so that's going to be a rather small subgroup.

Originally Posted by Magnetoman
Given that internal combustion engines are very tolerant of wear and abuse, so that rebuilders can "get away with" being quite sloppy when working on them, how should someone working on old bikes look at this? An aftermarket bush pressed into place might work OK as-is, but the only way to know if the resulting clearance meets the original published specs and it won't fail prematurely is with a precision measurement instrument. And the only way to deal with it if it doesn't is with a hone. However, are such things, out of sight, out of mind? Is time spent on the mechanical internals, beyond getting them "good enough," time wasted?
That's always a tricky on. Later BSA and Triumph workshop manuals were quite good at providing torques, tolerances and wear limits, and I think most people will work to those figures. The rules of thumb for fits and tolerances for different materials are available, though not so readily.
Material selection and heat treatment is a rather more esoteric area, and often involves cross-referencing between not entirely compatible standards.

The question of "good enough" is another vermiform container. Production pressures meant that the motorcycle factories worked to the "good enough" level, which is really what the figures in the workshop manuals show. Competition shops blueprinted to some extent, but even then practical factors of time and staffing came into play.
When all is said and done, even the designs were compromises, often working to greater safety margins than necessary to allow for production line and maintenance realities.

After many years in the "mechanic" category, I finally have the time and space to put together a half-decent machine shop, and try to learn how to use it. As such, the machining discussions are quite invaluable, as are some of the Youtube channels (kommando, I quite agree about Joe). As magneto man said above, winnowing the wheat from the chaff online can be quite a challenge. Even the better examples on Youtube have blind spots which may not be immediately obvious without sufficient experience to know when they're wrong.
In other cases, it's obvious BS.

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Given that most of these old crates were produced on machinery that would
be termed scrap by some people's standards my own feeling is that spending
inordinate time and money sending my machine work to the National Physical Laboratory
will never make these things much better than they can be by just applying general
good practice and accepting there faults. Blokes who remanufacture engines as a
facsimile of what they were are not ending up with the genuine artificial anyway.
For example, how many goldies did Phil Pearson build at BSA using genuine bits and
their machinery?

A ford Cortina rebuilt by Cosworth/Vandam Plas is still what it is,,,, a Ford Cortina.
Some people will obsess over stuff but others just don't worry about it.
Some people love to lecture and make youtube videos telling everyone how clever
they are, other people would just rather ride their bikes.

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Originally Posted by Chris Johnson
It can be horribly time consuming or expensive to make certain repairs correctly. It’s far easier to refinish something to look nice and leave the finer points of the mechanicals out of sight, out of mind.
I don't think everyone understands that it can be horribly expensive just to return many things to as-original specification. Also, people who buy into the urban myth about the Bronze Age quality of the original machining don't realize how much improvement to lifetime and functionality can be made by simply blueprinting the the engine and gearbox, i.e. making sure they have the specifications the designers gave them. I suspect Alp Sungurtekin didn't go 175.6 mph on a pre-unit Triumph without having done more than just bolt the engine together.

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quote
I suspect Alp Sungurtekin didn't go 175.6 mph on a pre-unit Triumph without having done more than just bolt the engine together.



Yes, i bet he just blueprinted it eh?

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To go one step further I have difficulties with people who don't know how to ride the bikes they have anyway.
No matter how carefully put together if the person doesn't know how to operate it as the factory intended then you have an unhappy marriage with everything being blamed except the riders lack of knowledge. Woe betide the person who tells a fellow motorcyclist he doesn't know how to ride
.
Modern motorcycles have more or less standardised controls. You can move from one to another expecting to find the basic controls, brakes, clutch, throttle, etc in the same place and working in the same manner.

Not so with earlier machinery, Not only can the controls be wildly different they often doesn't respond well to a new rider trying to modify these controls to suit their riding style rather than them changing to suit the bike. The classic case in point is the modern self closing twistgrip throttle. This is not a happy combination with either a hand gear change or the need to give hand signals (not that many other road users appreciate them anyway) and certainly not with an elderly two-stroke lacking an ignition key where the engine is intended to stop when the throttle is closed. I have an ongoing role explaining the reasons behind the adjustable friction screw on AMAL twistgrips and that twisting the throttle off as well as twisting it on can make for a much more relaxed riding experience.

All in all I think a high proportion of older bikes aren't ridden that much because the owners don't know how to.

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This thread already has had some interesting responses to the questions asked in the original post. However, people who aren't interested in the the subject of this thread are encouraged not to post here since it only detracts from those who are interested.

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"Beyond the pleasure that doing such precision mechanical work might bring, in monetary terms are you (me) wasting your (our) time? "

No, personally it gives me great pleasure to assemble mechanical stuff with the correct fits, I like to think that it will make the bike better to use.Usually this involves refining poorly made parts so that they will operate correctly.


"Are people who buy restored old British motorcycles today unlikely to put enough miles on them to reveal shortcomings in the mechanical work?"

Sadly , yes, in my LBS I have seen several examples of old bikes which were only fit for gazing at in the garage, new chrome and paint, dreadful mechanicals.



"Would someone pay any sort of premium at all to buy a bike with documentation showing details of the mechanical work, or is chrome and powder paint all that really matters? "

If i was in the market for an old bike , yes , definitely to documentation, I would be put off by shiny chrome , particularly exhaust pipes.


"Does the average buyer of an old British motorcycle (as opposed to the average Youtube video maker) know enough, or care enough, about the mechanical aspects to even judge the quality of, say, someone else's work to install new guides and seats?"

Thats a tough one, very few purchasers would be in the position to strip a motor prior to purchase. i would view any potential purchase as a potential grenade unless it came with receipts from Phil Pearson, or some other bona fide specialist marque machine shop.
My own interest is unit twins, i paid over the odds for my current bike because I knew the motor had been built by Devimead.


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Originally Posted by Magnetoman
Originally Posted by MarcB
this would then assume that ... anyone who's providing the documentation is patting themselves on the back
No, you've made an incorrect inference. It's common practice for a mechanic to provide copies of receipts, or an itemized list of out-of-pocket expenses, along with their bill for labor. It's not patting themselves on the back to provide documentation for the $20 to buy a valve guide, so why would it be for providing documentation showing how they installed that guide?

I guess my point here was that the guy that measured everything and nailed every spec perfectly will include this in their notes. The one who lets a few tolerances slip here and there won't.

But the inverse isn't also true. The guy who doesn't provide documentation isn't necessarily doing so to hide shoddy work.

So, as the client to a machinist or mechanic it is probably important but the question wasn't about the services rendered. It was about purchasing a restored motorcycle. To me as a classic bike buyer, the documentation is nice-to-have but I'm not going to pass up a purchase because it's not included. The $20 for valve guides helps set the price of the bike, but the tolerances do not (at least, not to me).

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Random post to test the inline embedding function.
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Will delete soon.

First bird-caged cable end this a.m..
Cheers to Cyborg for his tip on Laphroaig 25 Year as a quench.
Does give it a lovely nose.


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I am not a machinist and I have to rely on others for that type of work. On the mechanics side, I had to learn to do the work myself because I didn't have the money to pay someone else. As a result, I have progressed from being a dreadful mechanic to simply being a poor one. However, even as a poor mechanic, I have found that much of the work done by commercial shops on British bikes doesn't even rise to my level. While I appreciate the difference when work is done to the level that Magneto Man is discussing, I do wonder, however, whether for most purposes, if perfection isn't the enemy of "good enough." I also question whether working to that standard would be commercially viable. Years ago, I had a broken fin on a cylinder barrel. I spoke to a very high end Harley race shop that a friend had ties to. They started talking about all sorts of problems that could occur and why it was important to use qualified folks like themselves. Then they quoted $200 to do the job. I went to a welder that worked out of his home and he did the job in 5 minutes for $20. It still looks great 20 years later.

Ed from NJ

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Originally Posted by edunham
I also question whether working to that standard would be commercially viable.
That's a very important question, and certainly has direct implications for this thread. But, it's a complicating factor that's hard to deal with in the context of this thread.

Originally Posted by MarcB
the documentation is nice-to-have but I'm not going to pass up a purchase because it's not included.
Private purchases usually allow for starting a bike and listening to how it sounds, and possibly even a test ride. Auctions do not.

Consider the following hypothetical scenario. A shiny bike of a type that should sell for ~$15k comes up for auction, and at the same time in an alternate universe the same bike comes up, except with detailed documentation of the mechanical work done in its restoration. Would the you in the alternate universe bid more for that bike than the you would for the documentation-free one? If you would bid $15k, how much would the alternate-universe you bid?

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Originally Posted by Gordon Gray
Wouldn’t it be difficult to prove that the work in the detailed documentation was actually carried out?
In the olden days of manual cameras and Kodachrome film it would have been difficult and expensive to document everything, but with today's digital auto-focus, auto-exposure cameras and phones, and inexpensive color printers, it would be easy and cheap. Yes, things could be faked, but that's an issue even for simple things (e.g. you could be charged for changing the oil and filter on your car, when the work was never done).

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Originally Posted by Magnetoman
Originally Posted by MarcB
the documentation is nice-to-have but I'm not going to pass up a purchase because it's not included.
........... A shiny bike of a type that should sell for ~$15k comes up for auction, and at the same time in an alternate universe the same bike comes up, except with detailed documentation of the mechanical work done in its restoration......
I can't help but wonder if we aren't looking a bit too closely at a false choice? For the average guy, buying a collectible is usually an emotional decision based on desire and opportunity, not a rational economic decision. If you want something rare that is seldom for sale, you will probably buy at your first chance. The professionals in the business know this and focus like a laser on what sells, the look or "eyeball".

For really high end stuff, documentation is almost always part of the price. This provenance, which can include repair details with loads of glossy photos, chain of custody records, significant race history, famous owners and so on is expected. But, documentation can be and is faked routinely. High end collectors have staff doing nothing but research on cars they own or would like to own so they can weed through all of it and make an informed buying decision..

And unfortunately, documentation is in my experience not a real guarantee of mechanical fitness. I've seen too many times well documented collector cars that were in absolutely laughable mechanical condition. All this applies to motorcycles as well.

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Originally Posted by Magnetoman
Consider the following hypothetical scenario. A shiny bike of a type that should sell for ~$15k comes up for auction, and at the same time in an alternate universe the same bike comes up, except with detailed documentation of the mechanical work done in its restoration. Would the you in the alternate universe bid more for that bike than the you would for the documentation-free one? If you would bid $15k, how much would the alternate-universe you bid?
That's hard to say because 1) I can't spend $15k on a classic motorcycle so, unless I expect the auction to close at half that, it's out of my league. And 2) if buying at auction I expect to save about 50% of non-auction prices. If I don't get to sit on it and ride it around the block, the value (to me) is greatly diminished. In the end, I think I would be fooling myself thinking that a well-documented example would be worth more to me. I ride my bikes and know that it's always one loose screw through the carb away from grenading.

I'll offer a similar scenario, though: my 1968 Spitfire could hypothetically sell for $10k as a perfectly restored example or $4k for a dirty non-running one. Mine is neither of those: it's the wrong color with mismatched hardware and non-period correct pieces. However, it's essentially a one-owner bike that's been on the road its entire existence (I have a picture of myself at the age of 2, 12, 22, and so on sitting on it), the engine was meticulously rebuilt, has all the right upgrades to make it a dependable rider, and starts first kick. In this case, I built is so I know what I have more than any piece of paper would suggest.

If I were to sell it (I'm not), to me it is worth the top-end of the price range and I have (some) documentation to back the points I made above. However, I wouldn't expect most buyers to agree... I think it would take a very specific buyer and I'm not sure how much of the documentation would help sway them. Hell, I doubt I would be interested in it myself if it wasn't a family "heirloom".

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Originally Posted by Stuart Kirk
I can't help but wonder if we aren't looking a bit too closely at a false choice?
I agree it's complicated, and there are various interesting issues that might make it seem hopeless to conclude anything. However, I think/hope it's not that hopeless as we navigate around all the trees to explore this forest.

I deliberately picked the $15k value in my previous post to place it between $5k, where the buyer should be happy if the bike is basically sound and mostly there, and $100+k, where there is a much smaller pool of potential buyers and they likely have different expectations. Also, the issues of possibly-faked documentation and provenance differ between bikes at $5k and $100+k.

I think for $15k most buyers would hope they were getting a machine that ran well in addition to looking good on the outside, so the question is if they actually were willing to pay more for one documented to have been properly assembled. I suspect for most people it would be largely an emotional decision to bid on a $15k British bike, but the question is if there is at least a tiny rational component to their behavior? And, if so, how many additional dollars that rational component might be willing to spend.

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Originally Posted by Gordon Gray
Wouldn’t it be difficult to prove that the work in the detailed documentation was actually carried out?


Further to this, difficult to prove it was carried out SATISFACTORILY. & CORRECTLY. ???

I was surprised to see in a recent thread here a number of well experienced folks who 'confessed' they had their own theories on torquing things - and to my mind were over-torquing things.
If I bought something they'd built, I'd want to strip it down, resurface things and torque them 'to the book'. ???
Not that they were selling things that they built.
And had a seemingly successful record.

While admitting that few if any brit bikes were ever DESIGNED to be torqued to any specific number,
most of the torques now quoted are what is termed a 'post hoc proctor rationalization' ...
(think of a number, and make it official ) !!

I'll also quote something I observed in chrome plating/electroplating classes.
One of the chaps had decided that the washing/rinsing stages should be omitted in his plating of things.
Since this "might promote rust". (!!).
The lab technician soon became involved, and laid down the law to him about contaminating HIS baths,
and if he persisted would be ejected from classes forthwith.

What if you bought something that had been plated like that though ?

Chrome in particular is famous for peeling off in whole sheets if its been contaminated in the plating.
A local shop had a v expensive Stutz front bumper peel off the whole chrome plate, and they didn't
even know what they'd done incorrectly. And that'd be $thousands ....
At least it didn't happen to the customer, when he went to polish/wipe it over.

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Originally Posted by Magnetoman
Turning to books, most motorcycle "restoration" books basically just describe taking parts off a bike, cleaning or replacing them, and bolting them back on.
The one restoration manual I bought for the triples was written by a complete idiot! Half the text is explaining the mistakes the author made. Granted, they're all mistakes we all made when we bought the bike 40 years ago.
Most times YouTube info is junk. I can't find two videos on painting which agree on the same air pressure settings.

Originally Posted by Magnetoman
Finally getting to the point, the acceptable quality of restorations in 1976 when Jeff Clew wrote his restoration book was considerably lower than when Radco wrote his just ten years later, and since then another 35 years have passed.
Perhaps it's more the precision of the parts available. I remember my first rebuild of a '74 T150, I didn't measure but I NEVER had to ream any part to size just to get it to go on, but that was in 1984.
I had this problem when I rebuilt my A65. I found one machinist who could grind the crank, another who could size the crank bushing, and yet another to bore the cylinders. And I'm still not sure that any of the work was done correctly. Frankly I do not expect to have to inspect a professional's work!
I found someone who replied yes to the question, do you have a torque plate to bore a T150. That yes answer was enough to give him my business.


Knowledge speaks. Wisdom listens.

72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
92 BMW K100rs "Gustav"
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...for the guy here commenting on doing 1000 miles per year...that is nothing to worrying about this or that perfect work by an specialized mechanic etc.
I imagine also putting those miles at low speed.
Years ago I heard a lot "how good" a given bike was, but barely had mileages...

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