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Manx Norton 40m Restoration (I hope)

75K views 161 replies 28 participants last post by  Cyorg 
#1 · (Edited)
I got a phone call almost a week ago, I missed it but the caller left a message. The message recorded poorly but my knackered old ears heard "I've got a couple of bikes", "restoring" then "Norton" then I though I heard "Manx" then "Seeley", "Surtees" and "Beart"! What the......... Best I call this guy back but best not sound too keen and perhaps I should give it few minutes? Bollocks I must have called him back before he had put the phone down.

The chap on the phone was an old racer, now 75 years old and still had two of his old race bikes, he gave me his name which was a little familiar then started to tell me about his bikes. One was a 1954 350 Manx with a Surtees connection and the other was a period built special which consisted of a 57 Beart Manx frame with a Matchless G50 engine fitted, the engine was the 3rd G50 AMC made and the full bike was constructed in 1958. All very interesting and right up my street, appointment made and the next day I went to see the bikes.

I met with a spritely gentlemen who then took me to the bikes. Both were hidden under piles of stuff, the Manx was in big pieces and looking very sorry, the Manx G50 was as last raced in 1972 and complete. I hatched a quick plan a decided the Manx would be the most problematic, probably incomplete and would take the longest. The Manx G50 I could get on with later in the year.

So what do I hope to do under this post? I plan to write a short post every few weeks accompanied by a half dozen photos of the restoration work as it progresses. Hopefully some of you will find it interesting and not too boring. I will detail the engine build and other parts if there's enough interest. This Manx has gone through many changes but these will be reversed and the bike restored to 1954/5 spec as requested by its owner. Or rather this bike will be a restored as the factory racer that in my opinion every "caferacer" owes a debt.

By the way the old racer had ridden for Francis Beart winning a Junior Manx, rode for Ray Petty, has won the Thuxton 500 on a factory supported BSA and endurance raced Laverda's for Mead and Tomkinson amongst lots of other stuff.
 
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#2 · (Edited)
1st Post

Perhaps the last post.

1st van full of bits: Tank, gearbox, engine and a box stuff including cambox, primary drive, carbs, engine plates......

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Started the strip today. I noticed the spark plug was only screwed in a turn so feared the worst.

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I was right! Cylinder thick with rust, piston solid! Yep that is a high comp domed piston in there somewhere.

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Not looking good in the timing chest.

Rust

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A poor mistreated magneto, which still sparks!

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The engine doesn't looks so bad but wonder what's lurking inside the cases? Will see tomorrow if I can get the bottom bevel off! But it looks like I've got work to do.

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#7 ·
Interest from me too!

I feel your pain, this is Porsche head off an engine I got years ago, after a little clean up…



That one shot water/mud all over a shop wall when I pulled the plugs and tried to turn it over. There's still a stain there 10 years later. Amazingly it did still turn over though!
 
#13 · (Edited)
I couldn't move the piston so I removed the cylinder studs and parted the cases and 1st look inside below.

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Then.......

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Started cleaning some internals so establish what's scrap and the internals are cleaning up ok. This is the oil scavenge tube form the very bowels of the engine is fine, so is the case thread!
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#14 ·
So. Given the quality of your work. And the epicness of your work ethic. You will have this running by Valentine's day won't you? :D

Love seeing the insides of these engines, even in sad shape.
 
#16 · (Edited)
Errrrrh no.

The crank with piston and cylinder attached are currently enjoying a hot oil bath; about 90 deg C. They can stay in the bath for a day or so.

When parted from the piston the crank must be dismantled and sorted, the bearing feels ok but it has to be checked and cleaned, I have no doubt it will be full of crap, the flywheels need to be cleaned and shot peened (and I might re polish). Crank flywheel pins mic up OK. And the mains are good. The drive side main is a works type and unobtainable, these are broader than the standard Manx drive side main.

The cylinder needs relining, I can see what looks like seizure mark on the bore (although the owner said it was running ok!), the piston is scrap. The bore has been shortened so thinking the engine has a 2 ring piston fitted. The cases also need cleaning out and then robustly blast cleaned and new chromate. The cambox doesn't turn God knows what's going on in there. The frames needs a lot of work too, wheels and forks look ok (hopefully).

I have another 6 bikes on the go ranging from close to finished to not started in the shop, I have started this one as some of the lead times can be very long so best get in the queue. Some of the cycle stuff will 4-6 months to turn up. Hopefully by late summer for this one.
 
#18 · (Edited)
It a customer bike.

The white stuff is oxidisation, the crankcases are magnesium not alloy and its not very stable stuff, it will bloom with very little provocation. This engine has be stored dry but in a cool garage if there's a reasonable change between day and night temperatures the workshop breathes and so does the engine. If the engine does this for 35 years the "white stuff" is usually the result. It does look worse than it is, if its painted with a thin oil the crystals will dissolve slowly and the residue can be removed with a little effort. In this instance the black chromate has been breached in a number of places so this coating needs to be reapplied to prevent further corrosion or rather slow it down.
 
#19 ·
I've found that sort of corrosion in several early VW engines I've brought back to life. The magnesium is a little thin around the sump plate on those, and fairly often the bottom of the case will fully rot out with the engine in the car and flat tires...
 
#21 · (Edited)
Magnesium engines - Never store a fresh or unused engine as you need to make sure everything is coated with oil inside, if you must wrap it 100% in cling film ans store warm. Never store a bike with fuelled or oiled or battery fitted. Do not run bikes on R that will be stored for long periods either, modern formula R is much kinder but still dries out and will oxidise get sticky. R is a one meeting only oil, its not meant to be used over and over again. Also if your engine runs on methanol you will need to drain the oil, refill the oil tank with a synthetic oil, run up then drain again. R and water (in methanol) love each other and will reek havoc in your engine. R will mix with fully synthetic oil (but not mineral oils), Amsoil do straight 30, 40 and 50 straight grade race oils which I have used in big Harleys and a few g50 without problems, or if the engine is plain bearing BE Miller CFS is superb. Block the exhaust and the carb and breathers, I make bungs to fit exactly. If the motor is a single bring the engine to TDC (roll back on compresson) to keep the BE out of crude that may form and the valves closed. Always spray the magnesium whilst in use with an anti corrosion spray, let it dry and do it again and again the more the better. Store the bike vertical on stands and under inflate the tyres. always cover the bike. Vac bags are fantastic for long term strorage but fragile for multi use. keep the temperature as constant as possible. In the house if you wife doesn't object, in the house if she does!

Generally - Bikes shouldn't be stored for years at a time, they need to be started and run for a minimum of 10 to 20 minutes every 3 or 4 months. They don't need to be throttled either but say to 50% of the revs when hot. Race engines should be warmed at a higher RPM than street motors to avoid knocking the hell out of the bottom end (high compression) and cams due to strong valve springs.
 
#22 · (Edited)
Engine strip is now complete, there's plenty of corrosion but should be ok. Oil pump is scrap as it cracked and the gears have some rust pitting which is too deep to ignore. The mains when removed looked horrible but will clean up fine, timing side main is perfect, the drive side is filthy but absolutely perfect with no measurable wear. The cambox however has problems, input shaft and bearings are shagged out and the top vertical bevel also. Everything else measures OK.

The piston was well and truly stuck and despite enjoying 36 hours in oil heated 90deg and being tortured under a No6 fly press with a little direct heat the piston would not move. So into a hydraulic press and the piston freed off with an almighty bang which frightened the crap out of the guy pressing the buttons. The crank has now been stripped and needs attention. The cylinder as suspected needs lining. So off to the blasters and then new chromate on Thursday for the magnesium parts, the crank and cylinder will be sorted in the mean time.

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This is a works type main bearing arrangement and fitted to 54 works machine only.

Brass Metal

The troublesome piston, it a two ring type as fitted to 1962 machines. We will keep to the later piston and cylinder. But might, if I can find and earlier cylinder, revert to 1954 spec. This will require that I change the bevel drive arrangement, fit a taller cylinder and 3 ring piston. And also a cambox mod.

Have been taking a look at cycle stuff. Specifically the tank which has had a life and is bashed about but at least it original Norton so worth repairing, both sides are dented and the top bellied. Even in this state it's still worth a small fortune. So this will be sent to my tank guy tomorrow. Sadly the oil tank seems to have gone missing during the bikes 44 1/2 year hibernation. So need to find another big foot tank (can anyone help?).

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I had a quick look in the box of bits that came with the 1st van of stuff and there is some good stuff hiding inside. A late Amal 10GP carb and float which is weir type, and a rare long snout GP which would be correct for this bike in 1954 / 55 and the correct float and mounting bracket also, the float type is bottom feed and can be prone to flooding but its correct! Also hiding inside the box is a correct primary chain oiler, clutch centre, a few original Doherty throttles, rear torque arm and host of other original parts like head steady and plate, front engine plates have turned up too.

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#25 · (Edited)
Now that all the engine parts are either with the blaster, an engineering workshop, in an oil soak or in the bin, it's time to take a good look at the primary drive and gearbox.

Clutch - The clutch centre has been welded, this is was a common period mod and by doing effectively removes the cushdrive and adds strength to the clutch centre. Disadvantage is that "no" cush in the clutch centre is not friendly to the engine, gearbox and drive train, or the frame! So it was decided to restored the centre and reinstate the shock absorber. Simple enough to face off the weld and then press all apart. As a rule running any bike without a shock absorber in the drive train is not a good idea and usually on British specials I will install clutch centre and rear wheel shock absorbers especially if its strong engine.

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The clutch is the earlier Burman 3 spring type for Norton (Burman made 6 and 4 spring versions too and see note below) and correct for this bike, plates both plain and friction are knackered likewise the chain wheel so need to purchase new. The chain wheel will be a road item narrowed down and further lightened by scalloping the basket.

Gearbox, which is also a Burman laydown type is up next!

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Note - There are two types of Manx (featherbed) clutches supplied by Norton, the Burman clutch fitted up to and including 1956 (1st seen in 1936) and the AMC Clutch in 1957 to 1963. These differ from each other as follows; The Burman has friction inserts in the chain wheel, the friction plates are driven via the chain wheel and the plain plates drive the clutch centre, also clutch adjustment is achieved at the gearbox and finally the pressure plate is steel. The AMC has a plain chain wheel with a friction back plate, the plain plates are driven by the chain wheel and the friction plate drive the centre. Adjustment is at the clutch pressure plate which is alloy. The main differences between the Manx and road clutches is that the Manx is 1/ Narrower, with slimmed down centre and fewer plates 2/ It is much lighter due to a scalloped chain wheel, narrow width and fewer plates and 3/ The centre has 6 bolts whereas the road clutch has just 3.

A simple mod to help the chain wheel run truer is to replace the roller bearing cage with all roller bearings you need 50 in total rather than the 15 fitted as standard. Also make sure they are 1/4 x 1/4, many dealers will sell you 6mm x 6mm or 1/4 x 6mm. Get the right rollers!!!
 
#26 ·
:D

awesome stuff as always!
 
#27 · (Edited)
The gearbox: Not a huge amount wrong. The bearings are ok with a little noise but will replace all, the shield on the sleeve gear bearing has been rejected from its seat so oil will leak from behind the sprocket, the other bearings are relatively cheap so will do these too.

There is a little wear on the driving faces of the gears especially 3rd (always 3rd) so will stone the edges to remove any burs, that stuff will end up in the oil otherwise and it is bloody hard.

Other than one dodgy thread in the gearbox case all looks good for a 60 year old race gearbox.

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The only real design difference in the business part of the gearbox (apart from ratios) are rollers in the sleeve gear. Not present in the road box. And the lack of a kick start. And yeah I know about the Daytona bikes but that was due to race rules demanding a Kickstarter, I wonder how many half wits have tried to kick start a long stroke 500cc Manx with over 12:1 compression and have walked home?

One thing that does annoy the crap out of me is parts dealers who supply AMC gearbox parts for the laydown gearbox, true some parts are interchangeable for example the bearings are the same size and the sprockets share the same spline but the sealing arrangements are different. The AMC box using a spacer and seal behind the sprocket and the bearing is usually non shielded however the Laydown box has no lipped seal, the bearing is shielded and the sprocket has a shoulder which butts up against the bearing. Often there's a big felt washer fitted which acts as a dust seal and oil seal (ish). So when I order laydown stuff from so called specialists and I get f*cking AMC stuff I get a little pissed. What can be confusing is that some convert the laydown case for the later seal arrangement and there is nothing wrong with that other than its confuses some parts dealers.

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Chassis next!
 
#36 · (Edited)
Have been a bit busy on other stuff lately and have managed to get three bikes finished and out of the shop. Then I got myself distracted by a 500 Norton Dominator and a Yamaha TZ350F both of which are coming together nicely.

However a small unopened box of parts for the Manx on the bench has been tempting me for a while now and some nicely vapour blasted gearbox cases next to it likewise. Time to build the gearbox.

1st thing is to wash the cases, although they have been vapored (mixed bead and high pressure water) and look super clean best to make sure there's nothing lurking. So clean out the threads with correct taps and then boiling hot waster and detergent, the hot water will open up the pores in the cases a little and release any trapped grade. Then a thorough blasting with compressed air. I had already washed the internal parts so all is ready for assembly.

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I decided to go for the layshaft roller bearing conversion, the original is a deep grooved ball race which has a habit of wearing fast and collapsing. The roller is stronger and is a good mod in standard AMC gearboxes. I am also fitting the original type shielded sleeve gear bearing with the oil deflector washer.

Cases in the oven for 20mins and the bearings dropped straight in. Always tap the "outer" race of each bearing to make sure are in correctly, they should make a nice bright sound if the are home. Next fit the indexing lever and the cam plate, no seals on the shafts in a laydown box (see photo below), then the sleeve gear remembering to fit the oil deflector between the gear and bearing and new rollers in the sleeve gear, the sleeve gear bush was good so left alone. One thing I did notice but not surprised by was the amount of oil that wept from the cases when in the oven. Not a huge amount one can do, welding 60 year old alloy that weeps oil isn't easy, there is resin vacuum impregnation but its not reliable on old oily alloy.

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Assemble the ratios: In an old gearbox assuming the gears are good I tend to do this by feel rather than measuring all. For example install a gear turn its shaft or slide it on its spline to make sure there no tight spots then fit its opposite and do the same make sure meshing is correct and shim if required. I build the box dry 1st so I can feel all the play in the bushes and floats. When I am happy I will take the ratios out oil and reinstall. Sometimes if a gearbox has too much end float but shims are in my opinion too thin I will surface grind the appropriate gear to allow the fitting of a thicker and more robust shim. Often thin shims will spread and break up.

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Layshaft needing a quick clean, note the roller race on the end of the shaft.

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There are no oil seals on the quadrant and cam plate shafts so I make these, a flat alloy washer with an O ring fitted crush is about 3thou to limit drag on the shafts, too much drag will make the gear change action sticky.

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New rollers in the sleeve gear, grease holds them in place for assembly.

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Inside the assembled end cover, different to the AMC box. Also the clutch lifter which is more like TZ than AMC.

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Trimming off the excess gasket, I hate it when I see engines with big lumps of gasket poking out!

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Finished, well nearly, just waiting for some new case screws and two new lower covers studs - 10 min job! The out cases on the early manx pre AMC gearbox were not highly polished, I will wire wool and solvol to get the final finish correct.

Still need to get to work on the chassis!
 
#57 ·
View attachment 18032
New rollers in the sleeve gear, grease holds them in place for assembly.
If you happen to stop by and if you would be so kind...I have a memory test for you. Was there a steel thrust washer between the sleeve gear and the splined bronze thrust washer on the mainshaft?
In a parts diagram that I found (link below) it is shown as #12. The gearbox that I have arrived in pieces and there isn't a steel thrust washer. The way it looks, the bronze bit #11 doesn't look like it would suffer from being run directly up against the sleeve gear. I can only assume the parts diagram is correct and it needs the steel thrust washer but it would be nice to know for sure. I also wish I knew how thick it was, because I probably have a couple squirreled away and don't imagine they are easy to come by. I would also appreciate it if you could steer me towards a good source for new parts and a decent parts diagrams.

https://andover-norton.co.uk/en/shop-drawing/409/laydown-gearbox
 
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