W/NG - mileage

 It occurred to me recently that the mileages I record against each of the maintenance activities in my spreadsheets are inaccurate for bikes which have had their engines rebuilt since I've owned them. 

This issue is not really a problem for any of them except the W/NG which I rode for a while before I rebuilt the engine, so the engine related maintenance activities are not being held at the right mileage. 

This became a bit of an obsession for a few hours following my return from a two week trip to France for my daughter's wedding. After a bit of digging I found this receipt for the speedo rebuild:

Since I didn't have any records of any activities against maintenance activities, though I have hundreds of blog posts recording to work I have done, I went through all the pictures I had of the bike showing the speedo and recorded the dates and the mileages:

• September 2017 - first ride in my ownership
• February 2018 - 185 miles
• September 2018 - 383 miles
• October 2018 - 422 miles
• August 2019 - big service, documented in this post, probably about 600-650 miles.
• August 2020 - the engine rebuild, probably at around 1000 miles
• March 2022 - 1485 miles
• February 2023 - 2023 miles
• April 2023 - 2124 miles
• April 2023 - 2133 miles
• August 2023 - ridden to Tom's, and pictured in this post. It stayed there for two years.
• September 2025 - retrieved from Tom's as documented in this post.

As will be seen in this blog, various small jobs ensued and the W/NG is now the daily rider. Maintenance is now properly documented in it's own Excel spreadsheet - listed in this page.

W/NG - a bit of maintenance and a run out

It's a beautiful day in Norfolk and after doing a lot of routine maintenance it's time for a quick run out to warm up the oil prior to changing it. We make a 20 mile round trip to Cromer to do some shopping.

On the way back we stop at home to drop off the contents of the panniers and find something interesting - leaving the bike running on the field stand reveals that it smokes on the field stand - and drips oil from the decompressor.

The reason is obvious when you think about it - the rocker box is drained down the pushrod tubes and on the field stand the whole rocker box is higher on the push rod side and will fill up with more oil than it would when standing vertically. Consequently oil goes down the valve guides and out of the decompressor...

The picture above is the giveaway to this theory - here the bike has been standing outside Morrisons for 10 minutes on the field stand but not running. There's barely a drop of oil on the ground and what there is is on the timing side. It comes from the magneto to chaincase connection I think.

Still, the decompressor shouldn't leak so we'll have to have a look at that yet again. 

I wondered whether the main nut was square to the rocker box and was successfully making a seal there but it appeared that the decompressor body thread was loose enough in the rocker box to accommodate any out-of-flatness. What wasn't so good though was the thread - it's 5/8" BSW but it has an undercut down to something like 9/16", so the 3/8" BSP Dowty washer I was using is way too big. Since I don't have a 9/16" sealing washer, I used a 13 x 1.5 mm O ring and a 5/8" fibre washer - we'll see how that goes whilst we order the correct parts!

W/NG - maintenance

 Amidst a couple of days of routine maintenance, greasing, oiling, checking stuff, chain adjustment, cables etc. I finished a couple of outstanding jobs on the dynamo.

One was the missing felt pad from the commutator end bearing;

The other was fitting the missing cable boot.

It's starting first time, though there seems to be a lot of piston slap and it's quite rich. 

There's also a lot of oil around. On the drive side it's clear the primary case is leaking; on the timing side we have oil coming from the back of the magneto chain case. I suspect it's not pulled up tightly enough...

Charlie's shed - adjusting primary & rear chains

 The Huntmaster clicked over 400 miles on a run recently and is bedding down nicely. Checking it over in the workshop revealed a front chain that was rather loose, and of course one of the issues that you learn when dealing with these old bikes is that if the front chain is loose the rear chain will probably be tight as sometimes the gearbox will move. 

It's time to have a look at both chains, and for this we will use the on board toolkit:

First stop is under the oil tank where we find the gearbox top bolt and the chain adjuster. Loosen the nut on the right a little bit and then use the chain adjuster to draw the gearbox backwards or push it forwards.

Next you need to gain access to the primary case so that you can inspect the tension on the primary chain and later top up the oil. If this is tight use a big flat spanner to undo the inspection cover:

Now you can see the chain. This should have about 3/8" up and down movement and this should be slack movement - the chain should not be stretched tight and you should not be putting much effort into moving it. If the chain is too tight you will be putting undue pressure on the engine main and gearbox bearings, not to mention the chain itself and the clutch basket bearing. Typically the chain will get looser as it wears and you will use the gearbox adjuster to draw the gearbox backwards by a little bit to tighten the chain. When you are done, leave the gearbox adjuster where it is and tighten up the gearbox top bolt.

Turn the engine over on the kickstart and test the chain in a couple of places to ensure it's not over tight anywhere.

Once the front chain is done, we can look at the rear chain. The Huntmaster has a fully enclosed rear chain case and the inspection point is behind a grommet which itself is behind the left hand side silencer. It's easiest to remove the silencer to gain access to the chain:

This is much easier on bikes with only a simple chainguard, but on this one we can enjoy the fact that the rear chain oiler is doing it's thing in keeping the chain clean and lubricated.

Once you can access the chain, slacken off both the wheel nuts and the lock nuts on the chain adjusters shown by the spanner in this next picture. When you tighten the rear chain you must make sure that both adjusters are turned by the same amount - count the flats - to make sure that the rear wheel alignment is maintained. Be really careful with this because setting up the rear wheel alignment is a bit of a pain. Do the lock nuts up when you're done and tighten up the wheel nuts again.

When checking the rear chain it's best to turn the wheel and sit on the bike, because a swinging arm bike will always tighten the chain when the swinging arm deflects upwards. Ariel recommend 5/8" chain movement with the swinging arm deflected to normal riding position and 1 1/4" to 1 1/2" with the bike on the stand. That's quite a difference and comes from the frame geometry - the swinging arm pivot is a long way from the mainshaft centre.

SQ4 - sump plate

 The sump plate looked a bit mangled when I took it out after the oil was drained.

After degreasing I cleaned it up using some clock cleaner which is an ammoniated fluid used for stripping the corrosion from brass and copper. It works very well on the gauze.

When I got it clean, I manoeuvred the washer that stiffens the hole for the oil pickup pipe out of it's wire prison. I managed to get it back into place and squeeze it tight to retain the gauze.

With that done I could think about refitting the sump plate. I destroyed the gasket completely when I removed it so I needed to make a new one. 

With a sump plate it's easy to cut a piece of gasket paper to the right shape and to mark the holes.

Punching the holes is the easiest way to make them tidy and I used the corner of the sump plate to complete the ring of gasket around the holes.

I cut the centre out with a craft knife - it will be big enough to use for something else.

When I drained the sump, there was around a cup full of oil coming out and of course the gauze was damaged. The pickup pipe was the cause of both of these problems in that it was out of position - too high and off centre. It's just a copper pipe retained with a bracket inside the crankcase so it's quite easy to bend it into the right place.

With some Threebond 1215 the sump plate is back on and the plug fitted.

Charlie's Shed - Maintenance Logs

This post records my bike maintenance activities.

This is a link to a shared Excel spreadsheet listing the maintenance tasks, the frequency with which they should be performed and the mileage at which I last performed them:

•  Square Four Maintenance Log

This post has been upgraded to a page. It's here.

Charlie's Shed - Ignition timing, and nearby jobs

Having fitted the new carburetter to the W/NG, I thought I would look over the ignition system before I shake it down any further. I was having trouble with the idle settings and I wanted to ensure the other maintenance settings were spot-on before I investigate the idle issue.

So this morning we are looking at ignition timing and some associated jobs. Our focus here is of course my 1942 Ariel W/NG, but the points are valid for any M01 magneto equipped bike - that's all the BSA pre-unit singles, Norton singles, Triumph singles & Royal Enfield singles.

Assemble tools

Get your tool kit ready. I always use the tools I have on the bike for jobs like this - next time you do it you might be grovelling about in the gutter, so it pays to make sure you have the right tools and that they fit the relevant fasteners.

For example, I once found my magneto spanner did not fit the points hexagon properly and needed to be opened slightly - I would not have been happy if I had discovered that out in the countryside, however sunny it was that day.

For this job, you will need a drip tray. The timing case will have some blow-by from the oil pump in it and you don't want it on the floor - you will slip in it when you are pushing the bike about, and then you'll drop the bike or yourself, or both, which will spoil your day.

Last thing is to put the bike in a high gear, so you can move the engine carefully from the rear wheel.

By the way, it is important that you do these steps in the proper sequence. Anything else is going to compromise the ignition timing and hence the quality of your spark.

Remove the spark plug

Use your tool roll plug spanner and tommy bar to remove the plug.

Have a look at the plug and deliberate over the state of your mixture, piston rings, and ignition timing. This one is verging on OK in my book - no oil, it's not burnt, but it is a little dark suggesting my mixture is a bit rich. I'll not worry too much about that since I have changed the carb and we are checking the ignition timing today.

Check the cable tension

The ignition timing is controlled by the advance lever on the left hand handlebar - at least it is on Ariel singles. Ariels use a 'tight wire advance' in that the lever is pushed away from you, pulling the advance cable to advance the ignition.

To start work checking the timing, we need to make sure this cable has a little slack in it. Look at the ferrule at the handlebar lever end and make sure it is seated properly in the lever:

The other end of the cable disappears into the magneto under this little rubber boot:

There is a cable adjuster under the boot. Have a close look at the cable ferrule again and make sure the cable is a little slack - if it's not, move the adjuster until it is:

Setting the points gap

The next step is vital - work on the ignition timing with the points gap set up wrongly is a waste of time - the timing settings will be way out. The thing is, when the points are closed, the position of the points heel or pushrod relative to the cam is dictated by the position of the fixed point: if the gap is set too wide (i.e. the fixed point is further away from the moving point) the points heel will contact the cam later than if the points were set too tight - which alters the ignition timing.

Start by removing the points cover from the end of the magneto - swing the spring clip aside, or unscrew the cover.

This reveals the points and the cam. You can see the shiny surface of the cam in these two pictures:

This is where it is useful to have the bike in gear - you can move the rear wheel to move the points. It's quite difficult to access the points from under the dynamo. This 1942 bike has the short 40W E3HM dynamo - access is even worse with the long 60W E3L. You may wish to take the dynamo off while you adjust the points.

Use your toolkit magneto spanner with it's built in 0.012" feeler gauge to test the gap - look for a light dragging fit.

Use the spanner to release the lock nut under the fixed point and adjust the fixed point. Feel free to move the point - on this magneto, it is much easier to access the points with them at the 9 o'clock position, though the points are closed at this position. You must move them back onto the cam (12 o'clock position in this case) to test the gap.

Don't forget to do up the locknut when you are finished - but note that moving the locknut usually moved the fixed point a bit. Test it all again when it's done up tight.

Checking the timing

This is what we came for.

The first step, if you don't have one, is to make a graduated stick. Mine is a Wagamama bamboo chopstick; it's a good idea to drill one end for a loop of wire or string - something to stop the stick disappearing down the plug hole.

Stick it vertically in the plug hole, and move the piston with the back wheel until the piston pushes the stick upward while you hold it vertically in the plug hole. When it is as high as it goes, make a mark on the stick aligned with some convenient geographical feature - a church tower, TV mast or even the top of an adjacent cylinder head fin.

This is 'top dead centre' or TDC, the highest point in the piston's travel. Use a ruler to measure some graduations above your mark - mark 1" in 1/4" increments, with something indelible like a Sharpie marker.

An aside that you might want to consider. There are obviously more accurate methods of measure the piston position and detecting points opening than the method I describe here. This method is simple, but not particularly accurate - it's 1920's technology not 2020 technology, but it will get you going and get you home.

Personally, I get a lot of pleasure from this low-tech approach; I also ride my bikes on roads that existed when they were built and remember, with a manual advance magneto, the lever can be moved at will - there is little point in setting your piston position to the nearest half-millimeter when the lever setting is so inaccurate.

Next, wind the piston backwards and put your thumb over the plug hole. Turn the wheel forwards until you feel the air pressure trying to blow your thumb off - this is the compression stroke, where both valves are closed. Turn the wheel back a little way to bring the piston backwards down the stroke. Watch the points move around the cam, noting roughly where the points are when they open.

The Ariel I am working on uses a magneto which turns clockwise when viewed from the points, and the engine fires at something like 11 o'clock. In this case, I position the points at 9 o'clock, because I can get to them easily and place a blue Rizla cigarette paper between the points. Holding the cigarette paper, turn the engine unto the points release the paper.

Now, if I do this with the ignition lever set to full retard, the paper is released (and the engine would fire) at TDC. If I set it to full advance, the paper would be released with the engine about 5/8" advance, which we can see from the position of the stick:

The various notes Ariel issued for the bike recommend setting the ignition fully advanced at 3/8" - 1/2" BTDC, or 'Before Top Dead Centre'. Since my lever allows the ignition to be set between 5/8" and TDC, this is OK.

Remove the timing chain cover

You did remember to put a drip tray under the bike didn't you? The timing cover encloses the magneto chain and this is lubricated by leakage from the oil pump. consequently, there is always some oil within the cover and you will want to catch it as you remove the cover screws.

Check the chain tension

The timing chain needs to be maintained at a reasonable tension as it wears, or it will be carving your timing chest to pieces. If you look closely at this picture, you can see two grooves in that threaded post where the chain has touched it in the past.

The tension is not too critical, but there are a couple of points to bear in mind. Too loose, and it will be noisy and wear the case; too tight, and your magneto bearings and possibly the armature will suffer. Worse is a misaligned chain - it's quite easy to get the two sprockets out of parallel which is going to wear the chain very quickly.

The workshop manual for the W/NG says 3/8" total movement, which feels about right.

The chain tension is adjusted by moving the magneto backwards and forwards on its mounting platform. An Ariel magneto is retained by these three inaccessible bolts, which pass up through the mounting platform into the magneto. Slacken them by whatever contortionist spannering you are capable of, and pull the magneto backwards until the tension is where you want it. Before you tighten the bolts, make sure the magneto is pushed into the back of the timing case - there is a foam seal there which prevents the oil, splashing around the timing case, from coming out.

Set the timing

If your ignition timing was not to your satisfaction, you will need to loosen the magneto chain sprocket to reset the timing. Back off the nut a few turns, leaning on the rear brake lever as you do so:

Fit your puller to the large thread on the sprocket. You will have to wind the screw fully out to get it on, but once it's fully home you can wind in the screw and the sprocket will come off it's taper.

An alternative approach which you may find easier is to remove the sprocket on the camshaft rather than the sprocket on the magneto - the effect is the same, but the camshaft will not move while you put the sprocket back on, whilst the magneto might.

Set the advance lever to full advance and using your graduated stick, move the engine into the full advance position - 1/2" BTDC on my W/NG. As before, make sure it is on the compression stroke or you will have a mysterious failure to start.

Next, put your fag paper back in the points.

Turn the points by hand in the proper direction. They should move easily - you are turning the magneto armature which is no longer connected to the chain drive from the engine. Turn them until the paper is just released and no more.

Next, go back to the other side of the bike and push the magneto sprocket back onto the taper, and do up the nut. Go back to the 'Checking the Timing' section to make sure you have it set correctly; you don't need to be too fussy as the handlebar lever allows you to adjust the timing to wherever you want it.

Next, reassemble the timing cover; put the plug back in and replace the dynamo if you removed it, and go for a test ride.

Cake Run

Overcast and chilly but dry, and recovering from a couple of days with the grandchildren, today came another opportunity to give the SQ4 another test run after the summer oil leaks and HT problems which were eventually traced to be the cause of a persistent and long term misfire. Although the cold weather might be masking a hot weather running problem, the bike is running better than it ever has.

Preparing for the trip, I noticed the oil level was lower than expected, though a few minutes idling had it a little closer to normal. I topped it up, and resolved to look at it again when I got back.

A 27 mile around North Norfolk had me grinning from ear to ear as usual, though I thought the handling was a little uncertain; the brakes appear to be bedding in, the chain needs adjusting and the lower chain guard is clanking as usual.

Back in the workshop (after collecting the pear & ginger cake from the excellent Picnic Fayre in Cley), I set about adjusting the chain and rear brake. Since I was adjusting the chain, I removed the wheel to take off the chainguard - more on that in another post. I moved the chain back half a turn and lubricated it; I adjusted the brake up 3/8 of a turn and put an 1/8 of a turn on the front as well. The primary chain looked OK, and the oil level was good. I checked and nipped up all the spokes on the rear wheel.

Turning my attention to the engine, I had a good look around underneath. There was quite a leak coming from somewhere judging by the clean oil 'trails', possibly:

• the engine breather, which had a drip on the outlet pipe
• the sump plate or plug
• the front offside main bearing
• the oil filter
• the oil feed to the engine or to the top end
• a combination of several things

Essentially, there were too many possibilities to narrow it down. I tightened the oil feeds, the sump plate and plug, the crankshaft bearing cover and the timing cover but essentially none of them needed attention.

The front main bearing cover has a peculiar copper/asbestos gasket which looks more like an exhaust ring gasket and I suspect is wrongly installed. It's not the gasket I would have chosen for that application.

More later.

All quiet

Nothing happening here. The weather is terrible, but the tappets are done. Number 8 was strangely loose, and I don't think the 1 1/2 thou feeler gauge will last much longer.

Next I need to read this article, which may help me understand what is going on with these NGK B6HS plugs:

They look rather too cold to me. Maybe I should try a set of B5HS which will burn off that carbon.

Meanwhile, as it has been raining, I have been writing an article for the AOMCC magazine, Cheval de Fer.

Servicing begins

Well, its been a beautiful day here in North Norfolk, the sun is shining, it's quiet but I have spent most of the day in the office. A lunchtime walk revealed the tide out and an empty beach, just to underline how lucky we are to live here.

I had a couple of hours spare in the evening to repair some floorboards and make a start on servicing the Square Four. I had a number of jobs to look at before the summer season, so stripping had to start.

Its always a bit of a fiddle to get the oil pressure gauge line undone, and as usual I used only the tools I carry on the bike. This revealed that you need two 3/16" BSW open spanners, so I added another to the tool kit. Once the tank was off, I planned to remove the plugs, carburetter and distributor in order to re-torque the head and cylinder bolts.

The spark plug spanner I made last year is intended to replicate the one in the spare parts list, and it works well in getting to the number two plug which is now confined by the new bi-starter parts:

The plugs themselves, one to four from left to right are a little sooty; we will keep an eye on that, but there is no evidence of any oiling. The oil comes from the weeping head gasket!

Once I had the carburetter off, I was able to tackle the head bolts with the usual variety of spanners including my new baby torque wrench, using the torques Ariel specified.

I was able to get a half turn on most of the bolts, which I expected.

I planned on removing the distributor to turn it through 180 degrees, to put the condenser 'bulge' near to the oil tank and give myself enough clearance for a carburetter insulator. Having done this, and attempted to re-time the engine I realised that the position of the distributor did not now allow it sufficient movement to adjust the timing. Furthermore, there was no way I could add a carburetter insulator without new manifold studs - so back to square one.

However on putting the distributor back in I realised it was not turning freely - so off it came again. I found that the shaft was so stiff I could barely turn it by hand. It freed off, with WD40 and some light oil, but how was it intended to be lubricated? I could see the 3/32" hole in the body, and the milled flat down into the drive housing, but there was nothing to introduce oil to the shaft. Was I missing something? I think that there was a modification in this area for the Mk2?

Actually the modification Ariel recommended was to allow oil to drain out of the distributor but Paul Ptak, on the AOMCC Forum came to the rescue. He said:

Pull the rotor arm off and drip some light oil into the shaft? The machine screw under the rotor arm is drilled though and I believe the shaft is cross drilled to allow the oil to get from inside the shaft on to the bushings.

Why didn't I think of that? I've done it hundreds of times on distributors on various cars... I must be losing the plot. Thanks Paul!

So that was almost it for the evening. I didn't fancy rebuilding the distributor (good thing - I was obviously tired) but I did try the new-first-paint tank in place:

And I also stared to look at various missing clips. Having bits in stock, especially fasteners, is a wonderful thing. These are from Draganfly:

 Here's one I made earlier:

Obviously needs a hole and some paint but we will replace the one holding the brake cable to the mudguard with this.