This is such a trail of devastation through the engine, you have to feel for the owner who has probably already spent a great deal of money. The saving grace is that it will now be fixed properly by Dave 🙏

Great show.

I always enjoy these. I don't even own a British bike but it's fascinating to see how these were made.

you realy know your stuff dave.i enjoy your videos a lot

Wonderful that you are able to retrieve this machine from the precipice 👍👌👏

Thanks Dave. as iconic as old brtish bikes are, the more i see the amount of work and knowledge needed just to run them, let alone fix them; the more i get pulled towards not getting one 🙂

Very good Video which all owners of 'classic' bikes should see.

When you thought you were paying for Ogri to do your rebuild but it turns out Malcolm did it. Plastic padding; bloody hell.

シングルエンジンは素晴らしいですね👍😍🇬🇧

What a wealth of knowledge from experience and keen observation.

RESPECT Thank you for sharing !

There is a good video on KZfaq of an anti wet sump valve being tested on a jig setup, clear oil lines and a power drill to run the Norton oil pump. It lets you see how long it takes for oil to reach the pump from the very poor suction made by this type of pump. These rely on gravity to keep oil right down into the pump. The spring & ball valve arrangement means there is very little oil sitting next to the pump at start up. Video shows a good 5 minutes before the valve fully opens and proper oil flow restores. They then show their manual shut off valve with an electric micro switch to shut off ignition whenever valve is closed. Immediate oil flow to pump when opened, immediate oil pressure out of pump. Based on this, I made my own setup for my '850 Commando with a standard hardware store ball valve and a micro switch on the handle. Works a treat. No wet sumping and no oil starvation worries. There are a few vendors selling exactly the same setups for use on many different bikes (Feked web site has one; Holland Norton Works another). Mine cost my $10 in parts and a little time.

Very interesting video. In the process of rebuilding a 650SS. The sludge trap in the crank was so full with debris that it lead to oil starvation on the left journal. Had to regrind the crank. Will have to pay more attention to the pressure relief valve, thanks. Didn't know automatic anti wet sump valves existed for slimline twins. As far as I knew, Velocette is the only ones who fitted them. Not so bad on a roller bearing crankshaft but very dangerous on plain bearing cranks if malfunctioning. On Velos usually the steel ball will be replaced with a plastic ball.

Very informative probably the best! I run a 1975 Triumph Bonnie daily, taken years to sus out why it would run crap once stopped after an hour riding, the heat from the engine was being transferred to the carb boiling the fuel up , acquired thicker spacers for between the head and the carbs.. sorted!

Thanks for sharing this Dave, you’ve had to be a bit of a detective as well as a great mechanic with this one. I’d love to get an old British bike but when I see this I think I’ll stick to my old Honda for now.

Really very interesting video - I was glued to every moment and will send it on to others who will enjoy it too !! . . Sad to see the Norton has suffered so badly - I am glad that it is not beyond repair and is now in very capable hands for rebuilding . . . The Atlas is such a great bike . . Your workshop is so full if interesting machines - the wonderful Scott in particular - what a work if art that is - really looking forward to seeing it out and about with the "Chair" attached . . . Thanks again for this new video - very enjoyable indeed . . .

I would agree with Dave completely here. That bodge on the barrels is disgusting. You can take the crank apart yourself and there are studs or bolts available to rebuild it👍🇬🇧

G'day, thankyou for your excellent description of repair, to help me with my Atlas rebuild. Cheers mate

complimenti dave i tuoi video sono sempre molto interessanti

I really enjoy these vids, thank you

Dave love your videos. The video logs are good, but really like the videos where you recondition a bike. I have a T160 Trident and I ofter use your T160 reconditioning video as a reference. Cheers.

Thanks dave twas very interesting

Very interesting, an enjoyable watch. Cheers.

A great informative video, thanks.

I had a valve pocketed on my 650ss way back in 1977, really hard to set tappet clearance of course, and eventually it broke, went straight through the piston and that was that. The good news is, I took the plunge and rebuilt the engine and ever since then have been able to learn to do new jobs. Now I’ve got another 650ss, which I’ve also rebuilt the engine and box. Done about 600 miles,so far ok, thanks always to help from the experts like you guys.

Great job Dave! Keep up the good work!!

Great really enjoy the workshop videos, I had the same problem with the new valves on my Bonneville, I have mushroom type tappet adjusters and they made a furrow in the top of the valve, very disappointing, had to strip it all down again. They were a named brand as well.

Brilliantly put across Dave Great work 😊😊

Good and interesting video,mans a genius👌👌❤️

That Atlas engine doesn't surprise me. I had a two year old Atlas which had a 'vibration-broken' engine, and which had been re-engined with an undamaged 650SS engine from an accident write-off bike. The hybrid Atlas, now essentially a 650SS, never ran that well. Blue smoke always burn't out through the oil pump side of the engine, just that side only. Stripping it down, also only a two year old engine, there was a chapter of errors. Apparently the camshaft was 'bent' from manufacture, giving extra vibration again (they vibrate a lot at the best of times) and 'incorrect valve timing'. It also turned out that the righthand cylinder was receiving full high pressure oil delivery from the oil pump up through a drilling in the righthand big end upper shell bearing, much much more than was needed. The other side cylinder received an apparently correct amount of lubrication to the cylinder walls, so it was decided to replace the drilled upper shell bearing with a undrilled standard shell and determine if the oil burning on that side would be controlled. It was. The engine was still a dog really, when compared with another Slimline Featherbed I had in the garage at the same time, with a beautiful 6T pre-unit engine mounted in it, making it a 'Triton' . . really that Ed Turner designed Triumph parallel twin was in another world of beauty, power, smoothness, and reliability, and relative ease of servicing. Have you ever tried replacing the heavy one piece Norton Dominator head in position with just two hands? You need more fingers than an octopus has tentacles to get the pushrods correctly in position - it is just plain difficult and the process fights you. The Triton's 'Wheel-mark' 6T had been fitted with Bonneville cams and twin carbs. The power delivery was strong and seamless and smoothly delivered, all 47hp. The 650SS engine was pretty much everything the Triumph engine was not. At 6,800rpm there was possibly slightly more power (50hp?), delivered in a 'peak of raucous vibration' that was mechanically unpleasant and you could 'feel' that that engine was just another timed hand grenade. The contemporary BSA Firebird 650 was claimed to produce 54hp, however that fully encased unit engine also had the tendency to overheat and 'cook' the main bearings on either side. At least guys that was the story from back in the day. That Triton was the perfect combination of handling and usable power and surprisingly to the eye it looked as if it were just designed to be. The Triumph pre-unit engine was beautiful to look at. The bike was in mid-purple and black. It was just gorgeous from stem to stern. It made the most heavenly noises. It went like the wind through the mountains on a summer's day. Over the years of Japanese and Italian bikes it remains to this day the ultimate motorbike to my mind.

Always fascinating Dave - thanks for the clear exposition of what can go wrong. I have a 73 Commando which I fitted with an antisumping valve on the pressure side of the pump - plus an oil pressure guage for good measure. All good so far!

Thanks dave , another great video it's just like being in the workshop with you , keep this videos coming and where can I get myself one of your mugs cheers mucka 👍

As soon as Dave said "cutting out when hot" I was thinking MAGNETO, I've pushed many a bike home that has run great until it got hot and the windings / condensor in the mag gave up the ghost, leave the bike to cool down (after pushing it home) and it'll fire right back up. Mag off for a rebuild, get the old timing wheel out etc etc. Having seen the absolute miriad of problems with that engine, I'm amazed it even ran at all! I would have exclaimed bingo after finding all those, it's a FULL HOUSE.

Love your videos Dave..had an atlas in the 60s. Should have used superblend bearings as used in the later commandos when they stuffed their mains. From nz

As I have finally caught up with all 15 of your vlog videos, I have to say that I enjoy learning of the items to look for and to measure and inspect as I rebuild my '68 T100R. I have decided to tear mine down to the crank as I have no idea the mileage of the bike or owner history. Peering down into the crank cavity (I have the top end off down to pistons), a lot of sludge at the bottom, so I figure the trap needs cleaning at the least, so I will renew all bearings as well, start fresh. Looking forward to more vlog postings in the future!

I had a 650ss and at about 95,000 miles discovered it had no oil pressure 😮 where the oil pump feeds into the timing cover there should be a 1/4" blank, but was never fitted from new 😢 instantly the pressure was about 50 psi, Then discovered as it got hot the pressure was zero 😳 so I fitted an oil cooler and got about 15. I raced it for a while and even got a few wins, it was fast. It never did more than 10k miles between rebuilds. I later discovered the alloy heads are porous, just compare the weight to a Honda 500 twin. After riding cb750 and gs 750/1000 the Nortons were passed on.. Oh a good mate bought my Atlas and drooled over it, but his taste in Women was also suspect 😜 my last bikes were Huyabusa's , big soft rockets 😊

Excellent video Dave! I do wonder why people bother with these old bikes when modern ones are so well engineered and put together. I guess its nostalgic to see our motorcycling history back on the roads again, even though it ended badly for the British motorcycle industry back in the 1960s...

l bought a reconditioned Bonnie engine for a Triton project years ago. Misplaced trust meant l was conned into believing the engine was good....I'm of the opinion that 'bodging' is pretty common.. Nice to see a professional showing what sometimes goes on. As for my project l ended up seeking better advice plus new parts, including a complete renovation of the magneto ..once rebuilt the engine was a good starter and operated as spec...l had many years of riding the twisty country roads with just normal maintenance thereafter.

Great videos Dave,you know your stuff.

Dave Mitchell is lucky I'm thousands of miles away in the states and not within driving distance from wherever this is. He'd have to ban me from his shop because I'd be dropping by all the time, "What'cha working on, Dave? Mind if I watch? Happy to lend you an extra pair of hands." The oil pump on that Atlas is totally different than the pump on my 60's Triumph. I'd be curious to know how much all of that is going to cost the owner. That's a lot of work being done by top notch professionals. Adds up quickly. He'll have a beautifully running motorcycle when it's all said and done.

Great video. nearly finished my 67 atlas, found out that they differ from earlier models, Norvil have been fantastic, shipping parts to NZ. the last 10% feels more like 90%. i have so many questions! hopefully your next video will answer them, cheers.

Great video Dave. Are you going to the Stafford show?

Enjoy all your videos Can you do a carb tuneup balance for pre unit Bonny.

Couple of comments. Looks like head gasket was blowing a lot of oil. Head warped? Oil pressure relief valve should just barely rattle when it is properly shimmed. Gas BBQ grill works a treat to heat cases. Won't stink up the kitchen.

You can actually get the head off with the engine in situ, it’s tricky and you need to be careful with the pushrods which must be held right up tight to the tappets. Certainly doable though. PS edit, mine’s a 650SS, maybe Atlas is different…

Was the talk of crankshaft radius missed or edited out? Thanks for the videos, makes me wish I hadn't avoided the Trident refresh all those years ago.

Hi I have built more engines than I care to remember from RC model engines to truck engines they all have the same requirements and suffer the same problems watching your vid it would seem to me that most of the problem is the engine builder. There was no need for the plastic padding the dry liner would have worked just fine, it was probably the cause of the main bearing cage breaking up.The poorly fitted circlip is evidence of an inexperienced/careless engine builder the extra shims behind the pressure relief valve look to me as an example of trying to get more oil pressure and not understanding how the system works. The oil pump looks like it was the one fitted by norton it is hard to tell how much is damage due to dirty building and ware and tare over the years Keep up the good work

How many CC's will that add with a..040 overbore?Great video!! Can A50's or A65's transmissions be converted to five speed like on Triumphs ? Any other British bikes?

At what stage do you instead of fixing all the screw-ups it's easier and cheaper to maybe buy a recon engine?

Personally I always preferred the Atlas over the Commando

If the sump is filling with oil faster than you’d like, then the oil pumps knackered. So don’t go and fit a sprung ball valve upstream! I’ve never trusted them.

The barrel damage is classic broken con rod breakage damage

Boy I'll take wet sumping any day over a check valve or even a on/off valve that would lead to oil starvation. I thought Norton guys were all overly anal about their repair work... :P

that magneto is the wrong one for a Atlas it should be a Lucas k2fc First Atlas was made on 21st of April 1962 101xxx engine number

Oil does NOT pass between the pump gears! Oil is pulled around the gears in each of the gear teeth interstices. Just sayin’

If the owner paid someone to butcher his engine i would be looking for a refund WTF I could do better myself! I used my mothers oven when i was at home, i used to wait until she had gone out but she always knew - no matter how careful you cleaned the cases the kitchen was full of oily smoke. Don't think i ruined a Sunday lunch🙂

Norton atlas was UGLY+ CLUNKY compared to the norton 750 n15cs street- scrambler model < evel kanievel started out on a n15cs.

Hi. My name is Lemay. Nelson. My fraind fother had a Norton. Atlas. 750 cc. We used to. Disconnect. Speedo clock. and take it to okland California. USA. Bothe of us. Lived in fair oaks California. Finally. His. Fother found out what we were up to. His fother. Took us aside. And told us bothe. You can take. Her for a ride I don’t Minde. But. Leave the speedo clock alone. We wore the tires of it. But we put are money together to. Get new ones. That bike was a lot of. fun. Lemay. Nelson. Vancouver Washington Pacific Northwest. Thankyouso much.

I don't like putting a liner in cast iron cylinders, I refuse to do it on a 750 Norton because the liner is so thin due to the thickness of the cylinder, or lack of it, above the flange. looks like absolute cowboys have been in that engine! anyway, new cylinders, a grind and new set of NJ306EM1 superblends and it's a good un! The problem with British bikes is British owners!