To be filed under "What were they thinking?"

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A little story of woe that might be filed under the "what the %^&* were they thinking?"

I purchased a non runner mk3 a couple of years ago, just before I moved from Florida back to California. I finally tore in to the bike a month or so ago starting with a complete dismantling....

The first indication that things may not be quite as they seemed came with the discovery that the swing-arm was from an early 750. Ok, no biggy, can swap that.

Then I took a look at the tranny. It has the correct outer cover and the cross shaft. But strangely, so neutral switch. Opened it up and I find it's an Atlas case with an Atlas main-shaft. Complete with a slightly different end of shaft treatment that the Atlas has. So that needs to be changed, along with the case. Ok, this is mounting. Now we start on the main course.

The engine....drum roll

Off comes the head. Funny, I don't recall elongated slots in the through holes to mount to the barrel. Hmm....ah I get it, someone decided to use a 750 head and "make" it fit. Ok, more bodgery, surely that has to be it, doesn't it?

Nope. Let's crack open the cases shall we. Hmm, I wasn't aware that masking tape wrapped around a journal was a recommended way of getting an interference fit. Since the journal could still rotate they clearly hadn't used enough of it. And speaking of the journal, why were there fine grinding marks on one of the outer faces? There were no marks on either the case or the flywheel so someone had paid some attention to the bearing for some reason. At this point I'm faced with what I think is a totally trashed motor. Donning my Sherlock Holmes hat I couldn't get my head around the masking tape. The bore in the case seemed smooth with no evidence of a bearing ripping it up. So, I made a note of the bearing number on the journal and went to research a bit. What did I find? An imperial main bearing. Which has a smaller OD than the metric one that is supposed to be there. It was also wider, hence the grinding marks.

Oh crap, the inner race is also smaller, so did they grind the crank as well? Nope, the inner race they used was the metric one, the crank hadn't been buggered. That was the first bit of good news. The next bit was that when I offered up a good metric bearing to the case it didn't just drop in, not even "just the tip". So the case looks use-able. Now I know that when we buy old bikes we expect there to be some hidden problems, but these were really well hidden. Being philosophical about this, I will end up with a nice shiny head, a nice overhauled tranny, lots of new internals and everything back to being good with the world.

Now I have to track down a head, decide if I go std bore or 920 with some of those nice alloy barrels and if I go std cam. I also have to decide what grade of masking tape to use to fit my main bearings....
 

Fast Eddie

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Wow. That’s some ingenious botching!

The head should be salvageable, machine the head to take stainless steel ‘top hat’ plugs to the correct centres. Definitely doable. Whether it’s worth doing or not is another matter...
 
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I've done some silly things in my life, but..... the masking tape thing is just boggling my neurons. You are right... WTF were they thinking? I really must smoke some of what they had so I may comprehend the motive.

I hope your discoveries are over and things work out.
 
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I've done some silly things in my life, but..... the masking tape thing is just boggling my neurons. You are right... WTF were they thinking? I really must smoke some of what they had so I may comprehend the motive.

I hope your discoveries are over and things work out.
Some great news is that I have Rob North nearby (of Triumph fame) who has one of those "the smell of oil permeates everything" workshops here in San Diego. He's 82 and still kicking (although no kung fu any more). He can fix pretty much everything, except maybe my beer gut.
 

mean gene

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Once bought a BSA that had just been rebuilt, thank God it's battery was dead and it didn't start. Thought I'd open up the valve cover and have a look. Filthy dirty tor it down, lots of new parts but it looked like it was stored under a bench grinder. That's life
 
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Wow!
But seriously, could you smell pot cannabis when you stripped it down?
Whatever the engine bulider was taking it was introducing brain fade!
 
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Sounds like they threw it together just to sell it off for more money, instead of trying to sell it as a basket for less.
 

ashman

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Be aware there are bodgers everywhere even professionals who should know better and of course that concrete warranty when you ride away its non avoid and then there are the bike shops that don't seem to care who they rip off for a quick buck or telling their service guys to take short cuts but still charge you for things they never did, its the way of the world, sad really but there are still good honest people around.

Ashley
 

998cc

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Sounds like they threw it together just to sell it off for more money, instead of trying to sell it as a basket for less.
That pretty much sums it up.
Sadly, what the hack-job assembler was thinking is very clearly detailed in the evidence. Hopefully, you have gotten beyond the shock of the crime committed against the machine and can now focus on bringing it back to its former glory.

Regards,
Russ 998cc
 
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"Whether it’s worth doing or not is another matter..."

It's not. Sell it for parts (or just toss it) and write it off as a "learning experience." ;)
 

Mart UK

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I also have to decide what grade of masking tape to use to fit my main bearings....
Always plumber's ptfe tape with mineral oil, masking tape only with full synthetic...

I found a few things on my Mk3, like a RH shock not attached, because no washer on the retaining nut. Thankfully, a nice telltale vibration noise at idle. The best, so far, was an Allen screw in place of the plastic top hat spacer in the hydraulic primary tensioner. Caused the upper piston to seize fully down. That pushed the bottom piston fully out, stretched the chain, which wore a groove in the case. This caused sludge, which formed a perfect grinding paste for the sprag clutch bearing and clutch hub... Nice.
 
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This all sounds very familiar!

A few times now I have come across bikes with mismatched engine parts - two in particular come to mind when reading through the first post. There was a standard formula used on these, as the two were almost identical to each other in every respect.

MK3 primary (including electric start) - redrilled with three 1/4 holes
750 cases - combat i think, as the timing ear was solid, and the breather was on the back of the left half.
Weird barrels - 750 style (base fastening, not long thru bolts) but this was supposed to be an 850, so something going on there.
The pistons were mismatched and put in the wrong way
Badly machined heads with a lot of welding work - running inlet valves in the exhaust ports and the inlet valves so recessed they leaked very badly
All the electrics were Sparx (electronic ignition, alternator stator, rotor, reg/rec and handlebar switches)
No washers (or at least very few) were used on the bike and there were a lot of metric fastenings.

The owners paid a LOT of money for these bikes.
 

Carl H

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Your always better off buying a bike that has not been worked on ,, period , luckily I brought non runners many years ago when they were short money and not used or abused much, You could get them for about 500$ and they had great bones to build race bikes with. But always the transmissions needed lots of attention, but the engines were never worked on and butchered up.

It seems like the shops that did the work on Nortons had an inexperienced persons doing the work and it showed in the job they did on your bike and forget about a warrantee, they would just blame it on you, with a crappy excuse for the cause of the failure. HP costs money and you need lots of skills and tooling to do all the things needed to build a good modified engine.

If you can't degree in cams and do all the work to be sure parts don't collide with proper clearances, or have a shop that can do the work, your better off not trying it. A stock Commando can be a great bike set up by a pro.
 
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"Whether it’s worth doing or not is another matter..."

It's not. Sell it for parts (or just toss it) and write it off as a "learning experience." ;)
I go in to a bike with my eyes open. I expect there to be people who are quite happy to cover up crap and let you find out later. It's sad, but true.

No matter what I think it is going to cost to fix....it will be a LOT more. So I accept that. I also have a bit of a romantic side to me. There's something pleasurable about taking a sad piece of iron and making is beautiful again and bugger the cost. Great therapy is cutting out old spaghetti wiring and making the original work. As an ex design engineer I'm sympathetic to the guys who originally engineered something. It was put together as a whole and then we come along and improve things but often times those improvements are misplaced. These are some the rewards I get from ownership, I don't feel like the expense or time as a cost that must be recovered so much as part of the journey.

I'm not angry or terribly surprised, the seller in Florida was a pretty obnoxious individual - I found his bodges both amusing and sad. Sad, because there is someone in the world, who owns motorcycles, who thinks that spending time grinding up an incorrectly sized main bearing and then spacing it with masking tape and thinks it might actually work. My problem is the cost - his much more fundamental.

And look, we all enjoy the story, so there's even more value :)
 

BERT

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Yes there are thieves out there. I have been there too. One positive notion that set in my mind(after the initial emotions) was knowing I could never do that to another person and I sleep well for that reason.
 
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