About cyclemasterron

They say people become more like children as they get older and my wife thinks that's what happened to me. I prefer to think that I've gone back to my interests after many years of working for a living. Yes, I've retired! Yes, I have more (spare) time than since I was 4 and started nursery. And yes, I've gone back to tinkering with "things", hence this blog about my Cyclemaster.

4 days to go and I’m ready but it hasn’t been easy.

Speaking as a reformed pessimist, I’ve made good progress. The engine is running well following the re-build. There are no unusual noises, it doesn’t drip oil over the floor and more importantly, the blue cloud of exhaust smoke that followed me (and sometimes passed me) has gone.  So the exhaust valve seals are doing their job and I can be confident the engine internals are as good as I can get them.

But I had doubts about the oil pressure relief valve and in particular the pressure relief spring that had been over stretched. Few things will kill a good engine as quick as low oil pressure and nothing makes the engine leak oil like too much pressure. So after too much calculating and measuring, I fitted a new spring, attached a pressure gauge and was delighted to find 60 psi at the camshaft – perfect (I think).


And then, after a short ride I noticed the smell of petrol. It could have been a leaking gasket but no; the petrol tank had split on the underside.

Crack in LH side of tank.JPG

And then I realised I was legging it when pulling away uphill, like a 3 year old on a scooter, who’s just heard the ice cream van has pulled into the street. (those of my age will understand). No option but to reduce the teeth on the engine sprocket and no option other than to make one – old 18T sprocket for the hub and new 17T for the teeth – a cut and weld job that turned out well.

Race plates fitted and ready for action.


It even runs quite well and rides even better.

Now it’s off to Bologna for the start of Motogiro D’Italia 2018 and with luck, I may even make the end; riding that is and not in the back of the support van.

I’ll post my progress over the coming days – stay tuned.






I really do need my head looking at..

my cylinder head that is.

After making a second copper head gasket to get the correct cam chain tension and fitting the head, I found I could see light through the joint! Worse still, it was at the edge near where the oil gallery runs. So back off with the head and this is what I found.


Ideally the head and barrel should be skimmed on a horizontal milling machine to correct the “out of flat” but I don’t have one. So it’s back to my friends trusty old Colchester lathe to see if I can skim the head and barrel on that.

First problem was how to hold the head and I settled on making a frame from aluminium extrusion that I secured to the head using the 4 x M6 cam cover holes. I then clamped the aluminium frame in a 4 jaw chuck and trued up the head face using a dial indicator.

Using a new TCT tip tool, I skimmed the head, using a very slow cross slide auto feed, to get the smoothest finish possible and in total I removed 0.19mm.

To skim the barrel, I first made a plug out of nylon, that was a tight slide fit into the bore – tight enough that it needed tapping in place with a mallet but hopefully not so tight that it would split the steel liner.  The plug served 2 purposes. Firstly to allow the liner skirt to be clamped in a 3 jaw chuck without risk of crushing the skirt and secondly to keep the barrel true by supporting it with a floating tailstock.

To true the face, I removed 0.14mm. The good news was that removing a total of 0.33mm, enabled me to use the fist copper gasket I made; the 1,2mm thick one.

Now the joint is perfect and clamps up without daylight!


Job done (hopefully).

“I’ve been to Paradise but I’ve never been to me”

is a very, very, cheesie song released by Mary MacGregor, Charlene and others.

It’s about living a hedonistic lifestyle but never finding self fulfillment – very deep. Hedonists believe that their sole purpose in life is to maximise pleasure and happiness whilst minimising pain. Full-on hedonism is a bit extreme but I don’t see the harm in some pleasure and that’s what I’ve had with Sir Walter, since we became road legal in April last year.

Wherever we go, young children cheer as we go by (or is it “jeer”), teenagers point and laugh, builder’s mates hang out of transit vans and shout “give us a wheelie”, women often smile (sometimes shaking their head from side to side) and even Jack Russells are happy when they realise this is the first “motorbike” they can out run!

We’ve been stopped by pedestrians jumping into the road to ask, “what’s that?” and brought nostalgic smiles to men who were young in the 50’s and had a Cyclemaster as their first “motorbike”. One motorist even asked to buy Sir Walter, as “it’s exactly what I want for Steam Rally weekends”. Virtually everywhere we go, we strike up conversations with strangers. And we’ve been to quite a few places.

We’ve been on the East to West Adventure –

FROM CRIMDON DENE                            TO TEESDALE

AND HARTSIDE                                     TO WHITEHAVEN

We’ve been High and Low  –

Collage 2.jpg

We’ve been to Castles and Windmills

We’ve been to North America

Collage 1

and in the words of the song

“We’ve been to PARADISE


and we’ve also been to PITY ME”

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a great year all told. Bring on Hedonism.

go faster…. Cyclemaster?

Every motorcycle rider gets to the point where they want more power. For the Cyclemaster owner, this is usually as you are straining on the pedals up a steep hill, wondering if the engine in the back wheel is just a dead weight making your task harder. So what can be done?

First thing is make sure it’s running at its best, in standard condition. Critical things to check are ignition, fuelling and exhaust.

Getting the basics right.

1/ Ignition. The Wipac magneto needs to make a spark that jumps 5 to 6 mm in air when spun at around 1000 rpm with a drill. To get this you need clean points with a gap of around 0.016″, a good condenser, a flywheel woodruff key that is a tight fit (so peak magnetic flux happens at the right time) and an HT lead that is low resistance and not leaking to earth (often where it exits the case). For the timing, I find a little advance makes it rev out better but a little retard gives better low end torque, so you choose.

2/ Fueling. The first thing is to be sure there are no leaks. Often the Amal carburetor mounting breaks at one of the 4 segments where it clamps onto the steel inlet stub. I struggled with leaking here for months until a friend repaired it by making a new brass adapter that was threaded into the machined carburetor body.  Not an easy mod but it works perfectly.


The next place where you need perfect sealing is the crankcase. The crankshaft, drive side, rubber seal must be in good condition AND correctly positioned. The seal runs on a small step on the crankshaft and it can miss this step if either the seal or crankshaft are incorrectly positioned. The seal may not be pressed in far enough or the crankshaft may be too far towards the disc valve side – NOTE: the datum position for the crankshaft is against the drive side bearing – away from the disc valve. The pressed metal cover over the disc valve can also come loose and leak (as mine did), so check it’s sealed.


Next you need the right mixture to give maximum power (called stoichiometric mixture). I find the standard jet and needle are fine on the Amal carb, with the needle in the middle position, as recommended in the manual. The main thing that causes incorrect fuelling with a clean carburetor is flooding, either due to poor sealing of the float needle or vibration. I strongly recommend the carburetor is flexibly mounted – see my earlier blog    we have lift off – thanks to Bernoulli….

Finally, you need the correct fuel oil ratio. Remember adding more oil , weakens the air petrol ratio, and adding less richens it. I use Castrol semi synthetic at around 30 to 35:1, making the motor slightly rich which helps it run a little cooler, avoiding the risk of seizure, particularly on hotter days.

With everything set correctly, this is what my spark plug looks like. It’s perhaps a little weak but this was after a “fast” ride

3/ Exhaust. The exhaust ports and silencer must be clear of carbon build-up, or the motor will be well down on power. I regularly soak my silencer in a strong solution of caustic soda, even leaving it overnight. You can also drill a hole through the main baffle plate like I did to help the gases flow more easily.

So once you have the basics right, it’s time to think about more advanced options, if you still need more power. This is where I am at the moment, so none of the following modifications have been tried yet.

Advanced Options

To get more power from an engine you need to burn more fuel in the most efficient way, in the shortest possible time – easy? Maybe…

To get more fuel into the engine you could fit a larger carburetor and open up the inlet tract. Another way, would be to open up the slot in the disc valve plate, so it’s open longer. I’m not sure of the standard timing but it could be open from just before bottom dead centre (BDC) to just after top dead centre (TDC). Opening just before BDC would perhaps allow the suction through the transfer ports, to draw in more fuel.

The next step is to get more fuel above the piston. This is done by removing metal to open up the transfer ports and even cutting slots in the piston skirt and barrel to make the transfer passage as large as possible. Another way, (that has been used on Cyclemasters I’m told) is to raise the cylinder by fitting a spacer between it and the crankcase. This has the advantage of also opening up the exhaust port for longer, so the gases escape more effectively. I’ve heard it said that the exhaust port is the limiting factor on a Cyclemaster engine but I don’t know if it’s true. I’ve calculated that a 1 mm spacer would open the transfer and exhaust ports for approximately 38% longer, so this could give a very significant power increase.

However, if you raise the cylinder you need to machine a similar amount from the the cylinder head to avoid reducing the compression ratio. If you remove more then the compression ratio increases and the downwards pressure on the piston increases, improving power output. I’d probably remove metal from the top of the cylinder, rather than the head, to maintain the same gap between the piston and the circular profile in the combustion chamber.

You then have to ignite the fuel, consistently at the optimum time and to do this you need electronic ignition. The good news is that there are cheap ignition kits available from China that can be made to fit, particularly if you have a friend with a machine shop, or have access to machines and can use them yourself. The kits are the internal rotor type, so you are faced with 4 challenges

  1. You need to make an adaptor to fit the new rotor onto the crankshaft taper,
  2. You need to drill and tap the primary chaincase casting to mount the stator,
  3. You need to make a dummy flywheel to add mass to the rotor
  4. You need to experiment with the rotor position to get the best ignition timing as there’s no manual you can follow.

Here’s a photo of an Chinese electronic ignition that a friend fitted to a Cyclaid. He made an iron flywheel and tells me it starts much easier and revs far better.


Lastly, an expansion chamber could be fitted to get better suction through the engine. The shape of the expansion chamber is critical to give maximum suction at the desired rpm and a lot of experimentation would probably be required to get the tube diameters and lengths right.

Now for the extreme..

If time, effort, cost and complexity wasn’t a problem, then you could try these modifications:

  1. Bore out the cylinder to take a bigger diameter piston. The cylinder wall is quite thick, so the standard bore of 36mm can probably be opened up to at least 38mm, giving a capacity increase of 12.5% to 36cc.
  2. Rebuild the crank with an offset crank pin, to increase the stroke from 32mm to 36mm. This increases the capacity by 14% to 41cc
  3. Build a twin cylinder Cyclemaster by connecting the crankshafts.
  4. Fit the Cyclemaster engine forward of the seal tube, with chain drive to a multi speed hub in the rear wheel (e.g. 14 speed Rohloff hub – circa £1,000!!)

I say extreme, but I know people who have done these modifications, to a Cyclemaster so they do work.

Problem then would be, how do you stop a fast Cyclemaster?

Maybe that will be subject of my next blog?


How to pull a bearing out of a blind hole?

With the crankcases split, I decided to replace all of the bearings but one in particular was a problem as it’s fitted into a blind hole, so I couldn’t drift it out from the opposite side like I did on the others.


There may be an easier way but after a bit of head scratching I decided to try to make a threaded puller, that would go into the 15mm bore of the bearing and hook underneath the inner race. I started by turning a nut down to just under 15mm diameter on my friends lathe. I left a small step on one end at 16mm diameter for about 1 mm and then split the nut with a hacksaw, so that it would act like a split collet.


This also gives clearance, so the 2 halves will go into the inner race, with the step engaging under the bearing at the bottom. The plan is to screw a bolt into the split nut and hope it keeps the lip under the inner race whilst the bearing is jacked out.

DSC_0070 TEXT.jpg

I then made a steel spacer with a 36mm counterbore to clear the 35mm diameter of the bearing outer race.


and the finished puller looks like this.


I heated the casting with an electric heat gun to expand the aluminum and reduce the interference fit a little. Then I quickly screwed in the bolt, held the head and screwed the nut down. After a few turns it started to turn easier so something was happening, either the bearing was pulling out or the split nut was pulling through.


and fortunately it was the bearing coming out – job done!


One step forward and none backwards; now that must be a first!








115 days to go to the Motogiro D’Italia…

and it’s turned into a full engine rebuild.

I’d hoped to get away with minor bedding-in but the list of issues has grown to the point where I can’t trust anything,

  1. Burning oil due to to non standard O rings being fitted in the wrong place on the valves
  2. Cylinder head gasket leaking oil due to poor head gasket alignment
  3. Overhead Camshaft bearings not running smooth
  4. Cam chain far too tight as cylinder gaskets were too thick (hence cam bearing problem)
  5. Slipping clutch with springs shimmed up and going coil bound
  6. Excess end float on clutch basket causing clutch to rub on Primary cover at one side and clash a little with the drive gear when it thrusts the other other way. (helical gears)
  7. Gearbox input shaft doesn’t turn as smooth as it should, so there could be a bearing issue in the gearbox.

So that made my mind up for me. Full strip and check everything.


And it’s just as well I did. The previous engine builder had a preference for using silicone for gaskets and like most people, used far too much. It then squeezes into the engine and can break away blocking oilways, leading to total engine failure. Not something I want to happen in the middle of Italy…



a Cyclemaster for all seasons

It may be just me but I think historic vehicles should be used as originally intended. Not “wrapped in cotton wool” and trailered to summer events, or put into storage as an investment, as is common practice nowadays.

Thankfully, nobody in their right mind would buy a Cyclemaster as an investment and come to think of it, nobody in their right mind would go out on one, on a winter’s day when the temperature is -2C. Nobody that is but me.

Because that’s what owners did in the 50’s. You couldn’t be put off by the weather when you had a shift at the pit, or needed to get to work, whatever you did and neither will I.

Our route takes us along the snowy Bishop Auckland to Spennymoor Railway Path, formerly the Auckland Way Railway line that was opened in 1885.

DSC_0066 (4)

The line was built in two sections and passes through the 200 acre Auckland Park which was created over 800 years ago, as hunting grounds for the Bishop of Durham. The first section from Spennymoor to Byers Green belonged to the Clarence Railway Company and it was built to transport coal to Port Clarence on the River Tees in 1841, from where it went to London. Over 40 years later it was extended to Bishop Auckland by the North Eastern Railway, linking Bishop Auckland to the east coast main line.

Bishop Lightfoot was the bishop at the time of  construction and he insisted he didn’t want to see the railway from his Palace or even when he entered in his carriage from Durham. It’s a sign of how powerful the church was at that time, as considerable expense was incurred in making a cutting to hide the Railway and they even built special bridges for him to pass over. The bridges were extra wide and planted with trees at each side (and over the top) to hide the line from his view and they became known as the Bishops Bridges. They survive today, as Sir Walter takes a well-earned rest.

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However, maybe Bishop Lightfoot was right. His motivation was perhaps selfish, but it has left subsequent generations with two great public assets. A Railway Path enjoyed by walkers and cyclists. And a 200 acre park with a Georgian Gothic Deer House, a beautiful arched bridge over the River Gaunless just before it joins he river Wear, an ice house and a stone pyramid that caps an early water supply to the castle – hidden treasures yet to be discovered by Sir Walter.

Today demonstrates how rugged the Cyclemaster is and how the half million produced, transported their owners to work day after day and in all weathers. I just hope he recovers for his next adventure.


no going back …

as I’ve now booked my place on,

The 26th edition of the Motogiro d’Italia

that’s 154 days to get the MV sorted, ready and in Bologna for Monday 30th April 2018 for scrutineering. Stage 1 starts the following day with the sixth and final stage on Sunday 6th May, after which I’ll hopefully have covered 1576 km or 979 miles.

Motogiro D'Italia

There’s museums and other events along the route and we finish at the Ducati factory, who are sponsoring the event this year.

Next April sounds a long way off but the MV is in pieces and will be until January when the new clutch arrives. I’ll then have to hope the weather is kind, so I can fit in some long “settling-in” rides, complete with thermals.

and there’s the transport and logistics to organise

and a spares package to pull together

and I need to find out what this means:

“a TIME TRIAL event (MOTORAID) founded on: transfers, time check controls, time and stamp check controls and ability trials, that will take place in the localities described in the check cards. for the competition”

and the MV needs fitting with 3 event number plates

and it’s not charging and the speedo doesn’t work

and learning some basic Italian wouldn’t be a bad idea..

As I said there’s, “not going back” because the deposit is non-refundable. So if all else fails, I’ll be the first and probably the last, to attempt the Motogiro on a Cyclemaster.

(979 miles at 15mph average = 11 hours riding per day. That’s doable isn’t it? I may even get an award for the slowest ever finisher.)

In search of the source of smoking…

There are only 3 ways that oil can get into the combustion chamber:

  • up, past the piston,
  • horizontally, through a break in the head gasket or
  • down, from the valves.

So I’ve removed the cylinder head from the MV to find out which it is.

UP: The piston crown is clean and shows no signs of oil burn at the edges so oil is probably not getting drawn up past the rings. There’s very little movement of the piston in the bore which confirms it’s recently had a new  piston and I can’t see any scoring lines on the bore which would indicate a broken ring.  However,  I will remove the barrel later to be certain.


HORIZONTAL: There is a problem here, as the seal around the oil passage from the barrel to the head is poor, due to the hole in the head gasket being in the wrong place making it eccentric to the O ring.

Part of the O ring is under the gasket and part of it isn’t. This significantly increases the chance of oil leakage and explains why the front of engine was a little wet with oil. However, the seal to the bore doesn’t look like it’s been leaking, so this isn’t the cause of oil getting into the combustion chamber.

DOWN: To remove the valves I had to make a hairpin spring compressor and I then found the inlet valve was wet with oil – not good.

Next I inspected the exhaust valve and port and they were wet with oil – not good, not good at all!

The port is wet with oil around the valve guide and it hasn’t came through the combustion chamber or it would be dry.

THE CAUSE: Is therefore oil getting sucked down both the inlet and exhaust valve guides. Now most people think oil won’t get sucked down the exhaust valve guide due to pressure in the exhaust but this is not the case.  It’s true there are pressure waves but Bernoulli’s principle states that when a fluid increases its speed, the pressure reduces.  This is why carburettors suck fuel up the jet tube into the intake air, it’s also why aeroplanes fly and why you get some suction in areas of exhaust ports. There’s one final sign and that’s the small black patch of burnt oil directly below the inlet valve – see photo.

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This indicates a small amount of oil is dripping through the inlet valve when the engine is stopped then burning when it starts. BUT WHY?

There is some wear on the valve guides but nothing excessive. The problem, I think, is that both valve stems were fitted with an O ring just above the valve guide. Now I guess the previous engine builder expected the none-standard O rings would remain stationary in the alloy spring carrier plate but unfortunately they are going up and down with the valves. Not only does this make them totally useless as an oil seal, it actually makes them act like a reciprocating pump – one that pumps oil down the valve guide! When the valve is up, the recess below the O ring fills with oil and when the valve goes down the O ring compresses the oil and pushes it down the guide – not good.



THE SOLUTION: I could just remove the O rings and hope that this solves the problem. But it would be better if I could improve the valve stem sealing, as insurance and that’s what I’m going to do.  So it’s off the my local engine repair machine shop, where the owner “lends” me a large sweet jar filled with surplus valve stem seals with the instruction, “see if you can get any of those to fit” – happy days!

And it looks like one of these 2 types should fit, with a little trimming.


and then the finished job will look like this.


All I need to do is trim the underside of the valve stem seal, so it will seal effectively against the top of the valve guide. There’s a nice recess on the underside of the alloy spring holder that will hold the seal in place and prevent it from moving up and down, like the O rings – hopefully….


I’ve now removed the barrel and everything looks good. Virtually no wear and the piston and rings are near new. The piston is the 4 ring type (2 x oil control rings and 2 x compression rings) so the likelihood of oil being sucked up is very remote.


The piston ring gaps, measured 25mm down from the top of the barrel are:

  • Top compression ring = 0.65mm = 0.025″
  • Lower compression ring = 0.52mm = 0.020″
  • Top oil control ring = 1.21mm = 0.047″
  • Lower oil control ring = 0.42mm = 0.016″

The top 3 are a little bigger than I would like. However, current thinking is that ring gap is not as critical as previously thought and many modern engines run quite big gaps from new.

But to be safe, I will drop the piston manufacturer,  “Asso” an email to get their opinion.

So, it’s new gaskets and back together. I just need to decide whether to make a copper head gasket or buy a composite one, as some say copper is much more reliable.

a day of discovery…

as the MV is now road legal. So I’ve been out riding to find out what is good… and not so good.

First the good. It’s amazingly fast, extremely comfortable with fantastic brakes. At least compared to my Cyclemaster! It also generates quite a bit of interest  – probably because it’s red and Italian, a bit like a Ferrari to the 4 wheel petrolheads.


But there are some less good aspects. First, it’s smoking a little but I’m hoping that’s because the motor is running in, after the new piston was fitted (eternal optimist at large). And the fueling is very poor. It won’t idle and seems to be running rich. It hesitates at full throttle and then picks up as the throttle is rolled back.

So it’s another carb strip to check the idle jet and pilot circuit. Everything looks fine apart from the pilot jet is very small at No.35. Such a small pilot jet is most often used on smaller engines around 125cc and research saws the early version of this engine was fitted with a No.45 jet. As luck would have it, the spare carb bought with the MV has a No.40 jet, so it’s worth a try. Good news, it now idles OK but still won’t rev out correctly, regardless of slide needle position.

A quick bit of research on the excellent Dellorto website uncovered the original carburettor settings and for some strange reason both the main jet and throttle needle are the wrong parts. The main jet should be 102 and a 109 is fitted; the needle should be E12 and an E10 is fitted. The E10 needle is much smaller at the pointed end and this is the cause of the rich mixture at large throttle openings – problem solved.

But not quite.

The engine now pulls and revs much better but the extra torque is making the clutch slip….

and the battery is not charging……

and the petrol taps drip…….

and the speedo reads wrong…….

and the sump plate is leaking a little oil……

and the cam box cover is leaking a little……

and finally (for now) there’s the cam shaft oil feed mod I want to do. The standard method is to drip oil onto the camshaft from a tube mounted above it but this isn’t very effective as the spinning cam shaft just throws the oil away, leading to premature camshaft wear and failure.


The better method is to feed the oil through the camshaft (like all modern OHC engines) and this is the mod I want to do – WHEN I FIGURE OUT HOW.