we have lift off – thanks to Bernoulli…

and a few other things as well.

First, there’s the engine de-coke and re-build. Whilst doing this, I opened the exhaust port a little and opened the exhaust port throat a little more, smoothing the flow as best I could. A new crankshaft seal was fitted on the drive side and I took particular care to seal the small gap above the key way slot, in the primary drive sprocket, as some primary compression can be lost here. The little end bush also seemed a little tight, so the bush was gently eased using 1500 grade wet and dry sandpaper.

Second, I’ve flexibly mounted the carburetor. Now I was quite nervous about cutting the inlet manifold as there’s no going back but I did it anyway and fortunately, it worked out quite well.

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The advantages I hope to gain are:

  1. Reduced vibration of the carb that could be causing the float to bounce and flood with petrol; a persistent problem I’ve had,
  2. Reduced heat transfer to the carb from the engine, that I suspect is causing vapour locking , NB: Petrol boils at 95C, however ethanol boils at 78C, so modern fuel are far more prone to this. Sir Walter has always been a bad starter, 10 and 20 minutes after a hot stop.
  3. Increased clearance between the carb and the wheel as the petrol connector nut can touch the wheel, particularly if the wheel bearings are set a little loose. I cut 6mm out of the manifold and left a 3mm gap between the ends.

The finished job looks quite neat, as shown. You’ll see I changed to a different rubber hose as the black one above was too tight. I just hope the clear reinforced hose I used is ethanol proof, or I’ve a breakdown waiting to happen.  I’ve also added some thick black foam rubber around the inlet spigot, so that it’s supported where it goes through the carburetor cover.

Third, I’ve lapped the float needle to the petrol connector using a new method. Previously I’ve spun the needle in a drill whilst holding the petrol connector between my thumb and finger. The problem with this method is the lapped seat may not be axially aligned as it’s done outside the carburetor body. Consequently, it may leak when assembled.

First step is to make a nylon plug on a lathe, that’s a tight slide fit into the float bowl. Also drill a 1.6mm hole in the centre of the plug (on the lathe) to take the float needle, thereby ensuring the 2 diameters are perfectly concentric.

Then fit the petrol connector into the base of the float chamber with its fibre washer and tighten. Next put a dab of fine abrasive paste (Solvol Autosol) on the needle seat and insert it into connector and up through the nylon plug. Finally carefully tighten the chuck of a battery drill onto the exposed tip of the needle and spin it slowly for a minute or so.

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Repeat this, cleaning the needle each time, until a good even seat can be seen on the needle. The beauty of this method is that the new seat is perfectly aligned and shouldn’t (I hope) leak.

 

Fourth, open up the silencer to improve gas flow. This also makes it louder and it’s a scientific fact that something loud goes faster; or so it seems. My silencer is the type that doesn’t come apart (for cleaning), so I simply drilled a 10mm hole in the baffle plate that I could see inside the tailpipe. Yes, crude but effective.

 

So what’s this got to do with Bernoulli? Well in 1738 Daniel Bernoulli published a book called “Hydrodynamica” (great title), in which he detailed some principles of fluid dynamics.

In a nut shell, he stated that, “if a fluid (liquid or gas) increases its speed, then the pressure drops” and this is one of the fundamental reasons that a 2 stroke engine works. As the products of combustion accelerate down the exhaust port, they cause a drop in pressure that sucks the fresh fuel charge into the cylinder. So it follows that the faster the gases exhaust, the lower the pressure, the greater the suck, the more fuel is drawn in and the more power you get – simple. And that’s what I’ve done to improve Sir Walter, (amongst other things) and IT WORKS!

He can now climb steeper hills without LPA, he’s revving out much, much better and he even sounds fast.

PS, Bernoulli’s principle is why aeroplane wings generate lift, a spinning football bends, ships can’t pass close at sea, jetties always have water beneath them and why a F1 car’s areopackage works, amongst many other things.  Where would we be without Hydrodynamica?

 

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all is not well…

as Sir Walter has lost what little “get up and go” he had. Now he’s more “slow down and stop”. I always had to use LPA (light pedal assistance) on hills but now I’m doing it on the flat!  He also hasn’t revved out correctly for weeks, even when stationary with the clutch in.

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I’ve tried everything without success, so it’s time for a strip down to see what’s going on.

And the cause became evident very quickly. The Cyclemaster engine is already limited by the exhaust port area, so carbon build-up like this just stops it breathing. If the burnt gases can’t get out then the fresh charge doesn’t get sucked in.

Oddly, the transfer ports were also partially blocked up.

                           EXHAUST PORT                                    TRANSFER PORT

Restrictions like this have a very severe effect on a 2 stroke (negative unfortunately)  as they disrupt scavenging; the effect where the outgoing exhaust gasses suck in the fresh charge. Cyclemaster utilises Schnuerle porting, like the majority of 2 strokes.

Schnuerle porting loop scavenging

The cylinder has a single exhaust port and two transfer ports that are angled backwards. This causes the fresh charge to swirl away from the exhaust port and up towards the spark plug, minimising mixing of the burnt and fresh gases and improving efficiency. You’ll see the exhaust port opens before the transfer ports, when the piston is travelling down, causing the high pressure gases to vent through the exhaust. This flow of hot, expanding gases generates suction behind the flow, that helps draw in the fresh charge – at least when the ports aren’t blocked with carbon. And why have they blocked so quickly in less than 1000 miles?

I’ve added oil to the petrol in the correct ratio of 25:1 (or 4%). The recommended oil in 1952 was SAE30, so I’ve used Coma 2T that’s based on 30 grade mineral oil. It’s Jasco FB rated on ash content, so I expected it to be OK but it’s obviously not. Being positive, the engine hasn’t seized, which is a common problem with the Cyclemaster as they run very hot due to marginal cooling.

So what next?

When re-assembled, I’ll start with semi synthetic (Jasco FD) at 30:1 for a tank or 2, whilst the rings bed in. I’ll then change to fully synthetic at 35:1 and maybe even 40:1 over the cooler months.

And hopefully, Sir Walter will be back to climbing hills again.

I don’t know where this started but I do know where it’s going….

and hopefully, that’s from the East Coast of England to the West Coast, when Sir Walter and I partake in the East to West Adventure.

Or to be exact, from Crimdon Dean (famous North East Holiday resort) to Whitehaven (famous Cumbrian Georgian seaside town), covering a distance of 135 miles and crossing the Pennines with a total climb of 6,666 feet.

However, the build up didn’t go well. Ten days before the event I noticed a broken rear spoke. Oh well, perhaps one broken spoke would be OK? Then Sir Walter started to run weak, wasn’t revving out very well and had less pulling power than the elephant man in a nightclub. And then, when testing different engine setting, I hit a pothole and broke another spoke. So it was engine out, strip down and re-build with just a few days to go. This revealed a broken carburettor casting where it clamps to the inlet spigot (common problem) and I figured it was sliding back off the spigot and leaking air; hence the weak mixture. At this point I must give credit to Pete Stratford and Philip Crowder, who sent me the parts required, at short notice and enabled me to get Sir Walter back together the day before the event – thankyou.

Things were looking good on Day 1 at Crimdon Dean when Sir Walter started first spin, which is quite unusual but it impressed the watching crowd (4 people including my son Christopher). However, It quickly went downhill as the engine was revving even worse and Sir Walter seemed to want to be a plodding 4 stroke rather than a buzzing 2 stroke. Dropping the needle 1 notch helped but anything above half throttle resulted in Sir Walter going even slower. Not good, as a strong 18 mph headwind was forecast for Upper Teesdale. My enthusiasm was further dented when a fellow rider (who shall remain nameless but you know who you are) said I wouldn’t make it to Alston before dark!

 

However, things settled down and Sir Walter was reasonably happy at 5/8 throttle – I know because I’ve added graduated marks to the lever! Soon, I was caught “speeding” through Trimdon but please note, I only pedalled like that for fun and my son certainly found it funny based on the chuckling.

So onwards to Shildon where I tried advancing the timing but it was no better. And then on to Staindrop for lunch, where I tried retarding the timing but still no better. Then on to Egglestone where I tried reducing the points gap but, you guessed, still no better. Time to give up on adjustments and slog up Teesdale. And I did, through some of the best scenery the UK has to offer. Sir Walter was flat out (5/8 throttle) for one and half hours, with “gentle” LPA (light pedal assistance) and it was a delight to spend the time absorbing the wonderful views. This area really is one of the best kept secrets in the UK.

The only downside was the wind. Around Yad Moss, it was getting difficult to make forward progress and I was a little worried I’d get blown off the road and have to spend the night on the moor. However, I knew that support from Martin Wikner was only a phone call away… but I had no signal. And then Alston appeared and it was still light, even at 4:30. Oh yee of little faith, Sir Walter had delivered with a little help from me.

After a quick look around the Hub museum, which is well worth a visit, I then went back down the hill (not the best of planning) to Garrigill to find my B&B and a well earned rest.

The next day started bright and sunny, as Sir Walter posed for an early morning shot.

DSC_0041

Eastview Bed and Breakfast, Garrigill

Now, being the entrant with the smallest engine and slowest vehicle, I decided to get an early start the next day, and head for Hartside an hour earlier than planned. Some would call it cheating but I was getting embarrassing arriving everywhere last. As it turned out I was the third entrant to arrive at Hartside, looking a little like Laurel or is it Hardy. You just can’t get good passer-by photographers these days, or perhaps it’s the subject? Or was I just happy to have made it?

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It was now onwards and downwards, or so I hoped, to Hesket Newmarket in the Northern Lakes. This leg went well despite some surprisingly steep (up) hills that we just managed to climb under power – no walking for me and Walter.

And then dismay, in front of a large crowd at Hesket Newmarket, he wouldn’t start. So I pedal up the street with the choke on. Then pedal back down with the choke off and still no firing. Pause for thought, twiddle a bit (technical term), try again and heh presto away he goes. But it gets better. After a short distance, Sir Walter really starts to rev well and buzz like he should. Until that is, he splutters and stops. Good news is, I’d switched the petrol off during the twiddling phase. Even better news is, it proves the revving problem is flooding of the carburettor. Only dissapointment is that it’s taken me almost 100 miles to realise this and I only did it by accident; so much for being an “Engineer”. But now is not the time for a carb strip, so it’s onwards and upwards to Bassenthwaite where my wife and son are waiting to meet me at the Lakes Distillery.

The final leg is a leisurely run through lovely english countryside into Whitehaven via Cockermouth, where I arrive last as usual but extremely pleased to have completed the Adventure.

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Made it, and aren’t I pleased! So pleased, I even did a burn-out, Cyclemaster style.

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And we finished, albeit last to every checkpoint, including the finish. But as Philip Crowder said, anybody can do the East to West on a moped but I was the only one on a cyclemotor.

So the journey is over. Not just the journey to Whitehaven but the journey back to life for a rusty Cyclemotor that hadn’t ran for 50 years. And there is something special about a Cyclemaster; it’s to do with the way you have to work together, particularly when faced with a hill – you help the engine and it helps you.

Man and machine in perfect harmony, now looking for the next challenge.

Acknowledgments

I must thanks, those who helped me from the EACC. In particular Martin Wikner who drove support and Sharon who both planned the route (with help from Dave Watson) and rode it on her little red Honda. And thanks to Neil Catling for his words of encouragement.

And finally, thanks to my sons for their help: Christopher for getting me to the start, Daniel for getting me home from Whitehaven and Michael for looking after Mam and driving her to the Lakes Distillery to laugh at me.

 

a new record… and it’s broken again

Sir Walter phut phut, that is.

I say broken again but since making him legal, he’s done over 100 miles without serious problem. Not exactly JD Power top 10 performance but not bad for a 65 year old relic of the 1950’s. “Shake down testing” is the way I look at it. In preparation that is, for the Coast to Coast in June, over 2 days, East to West against the wind, with an overnight stay (or re-build!) in Alston.

And the testing, or development, has gone quite well. Sir Walter has proved he can climb some fairly severe hills with pedal assistance. And we have plenty of those in North East England, like the one below with Weardale in the background.

DSC_0085.JPG

Early on, it became apparent the engine was running very rich as fuel consumption was far short of the reported 240 mpg and the engine had a tendency to “4 stroke”. These small 2 strokes are often called buzz boxes due to the high pitch noise they make and when they 4 stroke, well, they just don’t buzz! Carburetor flooding was the cause and a sticking float needle was the culprit, quickly resolved by cleaning it and lapping the needle seat with Brasso.

As part of the “shakedown”, I found that Sir Walter pulled better with more ignition advance and started easier with a smaller contact breaker gap of 0.012″/0.014″compared to the spec of 0.018″.

Which leads me to the record of .. top speed.

First run, I got 24 mph. Not bad as the rated top speed is 20 to 25 mph. After correcting the fuel level, I got 28.5 mph. Then I achieved 29.5 on a long downhill with a tail wind. There was a “fast” left hander in the middle of the hill, with a sunken manhole cover that I hit. I’d like to say the suspension coped well but Sir Walter doesn’t have any, so it didn’t and I had more shakes than Shane Shakey Burn (BSB hero google him). Great fun.

Final try. After a bit more running in, I found a steeper and straighter hill, complete with left hander but no manhole cover this time. I gave full throttle and he revved out well. I even got down behind the bubble (i.e. headlamp) to improve the aero package. I got to the bottom safely and was hopeful I’d set a new record, when cough, splutter, phut phut … he died.

First thought were, seizure, melted piston and broken rings due to throttling off from high revs and loss of lubricating oil.

But I was wrong. Fortunately, on checking, I found that a screw had came out of the contact breaker assembly and I’d simply lost the points gap and spark. Better still, this is the Endomondo screen shot:

Screenshot_2017-04-21-22-15-50

So I’d hit the magic 0.3ton! A new personal record.

But you’ll notice my AVG. SPEED is low. And that’s because the screw was stuck inside the flywheel on the magnet and I had no puller to get the flywheel off, so I had to pedal home.

No support team for me, as I continue the British obsession for land speed records and tread in the steps of other famous daredevils. But at least Sir Walter and I have our own personal record; for now at least.

 

Michelangelo I’m not..

but as the great man said, “Genius is eternal patience” and that’s what’s needed to paint the Cyclemaster engine cover – patience that is; not genius.

So, after a quick rub down with “wet and dry” sandpaper, it’s on with the primer. I used Rust-oleum  for no other reason than it was cheap. I was unsure whether it was suitable for a cellulose based top coat but decided to find out!

For the top cost, I chose a silver that was close as possible to the original Polychromatic grey, then had it mixed at a local motor factors who supplied in an aerosol for a very reasonable £11. It went on well but dried to a flat finish as I’d got paint without lacquer. I did because cellulose lacquer is not resistant to ethanol and it would most likely lift on the petrol tank.

So the next problem was how to paint the red lines on the embosses and the black on the background of the Cyclemaster badge.

I started with the engine cover and found that a magnifying glass and a mascara brush worked well. Yes it’s the first time I’ve used a mascara brush, even though the result looks like I’m a pro!

The foam pad worked well on the raised embossing as it didn’t wipe down the sides like a brush would. However, the red flashes on the petrol tank and carb cover are different as the embosses aren’t flat topped – they are V shaped. So the first job was to mark the lines and I used my vernier set at 4.5mm to make some very small scratches. I then applied 6mm wide masking tape to form the straight sides. Now, the curved ends were a problem and I came up with what I think is a nifty solution; I used a hole punch to make a semi circle on pieces of masking tape.

These were then positioned to close the ends of each flash and the flash painted with a fine brush.

I removed the tape before the paint was dry, to prevent it from bleeding under the tape. Some “experts” recommend leaving it until the paint is dry but I was also concerned the tape may then pull the red off.

The final detailing job, was the black background to “Cyclemaster”. This was a really delicate job that I did with the smallest brush I could find. For some of the detailing around “MADE IN ENGLAND” I used the old cocktail stick trick; for example to apply the dot to the A’s – not easy.

TIP Boyes has a good supply of paints, brushes and masking tape etc.

The final job was lacquering and the big problem here is that it needs to be ethanol proof. The best lacquer for this is two pack and I found an aerosol called Pro2KClear made by Capella Solutions Group. It has a clever little ring pull on the bottom that releases the isocyanate into the paint to start the curing process. This worked really well, the lacquer went on easily and the results speak for themselves.

So far the lacquer looks very durable – scratch resistant and not yet affected by petrol spills.

However, as I said, “I’m no Michelangelo”. But a Cyclemaster is no Sistine Chapel and I’m as happy with the result as the Pope is with his ceiling – job done.

PS TIP Don’t use Humbrol Enamel for the highlights as it wrinkled a little when the lacquer was applied. At one point I thought it was going to have to start again. However it dried OK and the wrinkles can only be seen when examined closely which won’t be a problem when I zoom past at at least 20mph!

eat your heart out Mr Bluemels…

that’s Mr Bluemels of the world famous Bluemels Brothers Ltd. – manufacturer of automotive accessories and more importantly, number plates!

For most of the 20th century there was one motor accessory manufacturer whose name stood for top quality British Engineering and that company was Bluemel Bros Ltd.. Founded in 1860, at one time they manufactured a huge range of superb quality products including OEM steering wheels, auto lamps, cycle lamps and accessories for grand touring cars. They were one of the few regular suppliers to the bespoke coach builders of the 20’s & 30’s, catering to the likes of Rolls Royce & Bentley. As the coach built motor business shrank with the introduction of serious mass production in the 50’s, so Bluemel’s business evolved and by 1961, their portfolio included auto, bicycle, and motorcycle accessories, plastic moldings, dials, and number plates.

BLUEMELS-NUMBER-PLATES-original-1957

However, by 1983 the company faced insolvency. And like so many great British companies they folded. Worse still the name lives on in the guise of SKS Bluemel – a German bicycle mudguard manufacturer – how sad. And so typical of many other great British companies.

So, it’s down to me to make the rear number plate for my Cyclemaster. I doubt I can do it as well as the Bluemels Brothers but I’ll give it a try. The first thing I need is some material and I’ve “acquired” some 18 SWG mild steel sheet and some aluminium sheet. Applying the Colin Chapman principle, the ali would be better as it’s lighter and more suited to my puny engine and equally puny legs!. However, I’d prefer to weld the mounting brackets in place, rather than have unsightly bolt heads showing, so the steel it is; and I’ll just have to work on the legs.

So after cutting the required size, I scribe a line 5mm from the edge to form a “safety edge” (bent back, in other words). The line is positioned in the vice and the blank bent back using a rubber mallet to avoid denting the plate.

Each side is bent back to within 25mm of the corners. I then cut  a suitable radius on each corner with tin snips and formed each corner back, using an old socket.

I left a tab in the centre of the top edge for a rear light. Now, to keep the boys in blue happy, it should really have a clear area on the lens to illuminate the number plate and comply with the Road Traffic Acts. However, I’m a risk taker (and a cheapskate), so I’m just using the Raleigh rear light. My plead for leniency would go like this, “Being practical officer this autocycle doesn’t go any faster than a bicycle. So if you want to record my registration number, in the dark, just walk alongside (or jog if I’m going downhill) and ask me”.

Now I need mounting brackets; one at the bottom with a single bolt fixing i think and one slightly above the middle with two bolt fixing. Bottom bracket first. I cut a strip of steel then formed it into a U shape as shown below, using a suitable screwdriver as a former.

I then turned it over in the vice to close it up, then squeezed it back on itself.

After drilling and filing to smooth the edges and clean it up, the finished bracket looks like this. Ready for welding, once I’ve made the top bracket.

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Which is a bit more difficult, as I’d like it to follow the form of the mudguard. I started by bending a strip of steel around suitable formers by hand – my bike stand and a screwdriver in this case – see below.

However, my rear mudguard has a raised centre section so the bracket needs a relief groove to clear it. I formed this, using the vice (again) and a screwdriver (again) and a hammer .

and it turned out fairly well. Not perfect but the shape can be carefully improved by using (you’ve guessed) a hammer.

I just need to cut and bend back the tabs and it’s ready for welding onto the plate. To get the angle and length of the right, I used the well tried method of cutting a piece of cardboard as a template – easy to cut to get it right then use it to mark the metal.

Now welding is a bit like brick laying. You don’t need a degree in engineering, you just need years of practice and more practice. I wasn’t a bad oxy acetylene welder in my day but that was in the 70’s. And when I say “my day”, I mean ONE day! So, first thing is to set up the MIG in the “welding bay”.

DSC_0059

I’d love to say the weld below was my first attempt but it wasn’t. “Pigeon droppings” is an apt description of the test welds but it did come together eventually – unfortunately on the last one.

DSC_0061

And after priming and painting, this is the result.

DSC_0081

The last job is to fix the self adhesive alphanumerics and this can be difficult as you only get one chance. The method I used was to apply masking tape as a base line to get them level. I marked the tape with the position of each alphanumeric, leaving me with the task of making sure they were straight.

And now the final steps of drilling, fitting and standing back and admiring.

but the Bluemels Brothers would have nothing to worry about, had they survived.

and finally, some Bluemels adverts from Graces guide,

Im1951MShow-Blumels

Im19360610Cy-BB

Im19250306MCT-Blue

Im1920Cov-Bluemels1

and the last one is a gem.

blu_let-1

I particularly like the bit, “a junior member of staff (male or female) can handle the simple assembly procedure.” In other words, so simple a female can do it – sexism hadn’t yet been invented, just practiced!

And look at the name of the Sales Executive…..

 

First test run.. with a flat cap

because a flat cap makes all the difference.. doesn’t it?

But fitting the cyclemaster wasn’t as easy as the manual indicates.The biggest problem was setting the drive chain tension, probably because it’s badly stretched. I found that when I dropped the engine to tension the chain, the carb clashed with the wheel. So I tried turning the eccentric adjuster into the forward position, then the plug cap clashed. So then I fitted a shorter plug cap and that seemed OK.

The next difficulty, was setting the wheel cones – very important as too slack will cause wear and a wobbly wheel and too tight will overload the bearings, leading to early failure. Anyway, I eventually got a reasonable setting, only to find the drive chain was now too tight – back to square one..

After a couple of hours the bearings and chain seemed OK, so time for a test ride and here we go.. with a cap.

and it goes downhill but struggles up….or is that just me expecting too much from 32cc and 0.8HP? I gather the “secret” is to pedal early to keep the engine revs up and in its power band but I’m not sure it has one.

Great fun though and the back pedalling brake actually works but I won’t be leaving any black lines just yet!

And after a bit of tinkering it’s also ticking over quite well.

Next step is to make and fit a number plate. And yes, the DVLA have came up trumps and I have a nice new log book, with the original number and better still it’s transferrable.

However,immediately after my first ride, I got a “sign”. I received an invite from the buzzing club (The National Autocycle and Cyclemotor Club) to join them on the C2C in June – see link.

http://thebuzzingclub.net/news/coast-to-coast-2017-the-dates-in/

Two journalists did it last year on a motorised tandem and that set me thinking. One of my sons has an old tandem. Would any of them be up for it? Or perhaps each of them in rotation – wear one out, then swop.

And I could fit the Cyclemaster to the front wheel, then we’d have a full set of gears, rather than just one and that will help with the serious climb up to Alston.

I wonder…?

I’ll let you know..

 

 

 

beware, this gets technical….

so switch off now, if this type of stuff bores you.

In this blog, I’ve listed some things I’ve learnt when re-building my Cyclemaster engine and some tips that may help you. They are based on my experience but if you don’t agree with something,  then feel free to just ignore it.

1/ Put the small crankcase casting on after the clutch casting

You can then support the crankshaft at the opposite end to take the reaction from pressing on the drive gear and the clutch housing. This also ensures the crankshaft is fully into the drive side housing and avoids the risk that it may be mis-aligned and put excess pressure of the disc valve.

engine-schematic

However you must put a support between the crankshaft webs – see below

I measured the crankshaft web gap at 6.88mm, then found a spanner that measured 6.83mm thick – perfect. Just insert the spanner between the webs and you won’t damage the crank, if you have to tap the clutch casting on.

2/ Warm castings before fitting them.

This makes it easier to fit them where bearings are a press fit. I use a heat gun, gently, on low heat setting.

3/ Repair crankshaft taper and magneto fit

My crankshaft was damaged and the magneto wasn’t fitting correctly. This is the reason it sheared 2 woodruff keys. It also explains why the flywheel was loose when I got the engine and the Woodruff key was missing.

dsc_0003new-text-2

Look closely and you can see the crankshaft taper is swollen. This was repaired by gently filing the raised area down, then putting fine lapping compound on the shaft and spinning the flywheel without the key fitted. When the fit had improved, I finished it off by lapping the joint with chrome polish – Solvol Autosol in my case.

The flywheel still didn’t tighten onto the taper correctly and this was because the nut was also too tight, as some threads were swollen.

dsc_0018-text-cut

I used a gauge to measure the tpi (threads per inch) at 24 and my vernier to measure the thread OD (outside diameter) at 0.305″. The nearest thread I could find was 5/16″ x 24tpi UNF (Unified) so I bought a die to cut the thread so the nut would go fully onto the thread.

                       CUTTING THREAD WITH DIE                 FINISHED SHAFT

Hopefully that’s the end of my flywheel problems. Only downside is I’ll need a “Puller” to get it off now, as previously it just came off when the nut was loosened.

4/ Make your own gaskets.

It saves a little money and is quite a satisfying job to do.I’ve been collecting bits of brown paper for a while, so just select a piece that is the right thickness and rub it over the casting. It’s like tree bark rubbing but use a dirty finger rather than a crayon. Then I tap the holes very gently with a small spanner to cut them out.

Finally cut the profile, using curved nail scissors for the tricky bits if necessary. And this is the finished gasket.

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5/ Do a little tuning when it’s in pieces

I can’t be certain this will help but improving gas flow can’t do any harm. I polished the transfer ports and removed sharp edges, as shown.

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6. My tips for fitting clutch Hub

The Cyclemaster manual recommends you fully assemble the clutch plates, then fit the assembly to the output shaft (LH photo). However if you do it this way you cannot see if the Woodruff Key is correctly located. So I suggest you leave the cover plate off and fit it when the clutch is on the output shaft (RH photo) – see below:

Also I find it helps to hold the key in position with a small screwdriver down the back.

Finally check you can see the end of the key. 

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If the key is not in position you will have no drive and the engine will need to be opened again.

7. Amal carburettor

The main jet in the carburettor is very small as the engine is small and does not need much petrol. This makes the jet very sensitive to dirt and it blocks very easy. My engine was running badly then would not start so I cleaned the jet.

Some people say the filter disc from the float chamber must be fitted a certain way or the fuel does not flow through it. I cannot see why the fuel would not flow both ways but I turned mine anyway.

amalparts-crop-text

and now it starts, runs and idles well – see video. I think it was dirt in the jet but I can’t be certain; turning the filter may have helped.

After running for 30 mins at low revs the spark plug looks like this. 

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It’s dark brown which indicates perhaps a little rich but this is better than white as that indicates too lean, which can lead to piston seizure. So I’ll leave the fuel mixture as it is, until the engine has done more mileage.

But to do that, I’ll need to get it into the Raleigh, or “Sir Walter” as he’s called and that’s the next job.