Shakin' Strumpshaw Steam Rally

This years Strumpshaw Steam Rally provided the perfect opportunity for a decent ride, a lovely day out and the chance to shake out some more SQ4 problems.

Strumpshaw is a village in my home county of Norfolk located on the northern bank of the River Yare around 6 miles south-east of Norwich within the Broads National Park. The village lies a little distance from the river, on the slopes of Strumpshaw Hill, the highest area of land in the Norfolk Broads.

Strumpshaw Hall lies closer to the river, next to the Yarmouth & Norwich railway line from Norwich Thorpe to Yarmouth Vauxhall, first opened in 1844. It is the home of the Strumpshaw Hall Steam Museum, with a collection of traction engines, steam rollers, 100-ton working Beam Engines, a Narrow Gauge Railway, a 1930s Fairground, Mechanical Organs and much Memorabilia collected over many years by the Key family.

The Strumsphaw Steam Engine Rally is held each Spring Bank Holiday Weekend in the beautiful parkland grounds of Strumpshaw Hall. The rally hosts over 50 traction engines in steam and some 350 other exhibits including vintage tractors and heavy horses, stationery engines, fair organs, working demonstrations of steam and tractors, classic cars, trucks, fire engines and motorcycles.

It's the perfect spot for a ride out to meet the grandchildren, especially if the weather promises to be sunny.

The ride down quickly revealed that the steering problem had been fixed by proper adjustment of the wheel alignment, but that the chainguard was still a problem.

This KTM was the only bike to join me in the car park... It looks like all the other bikers registered their bikes as exhibits and got in for free:

The best part of the shakedown was the results from the carburetter temperature testing. After a 69 mile round trip with no misfire, and a 22 mile trip back at 55-60 mph we have these results, taken with the engine running in the yard and measured immediately upon arrival:

• 208°C on the fins near No.2 spark plug
• 131°C on the inlet manifold flange - near the offside carburetter stud
• 80°C on the carburetter flange, 1/2" from the 131°C measuring point but on the other side of the phenolic spacer. That's a 51°C differential across the spacer.
• 47°C on the float bowl.

Ambient was around 20°C for most of the trip. I measured the other cylinder head temperatures as well and added them to my chart with some previous tests:

Looking at these results, there is an issue around the focus of the thermometer. Normally I point the targeting laser on the plug body from about 15" away, which probably means we are measuring a 2" circle around the plug body; for Test 5 I aimed the laser at a fin and probably ended up measuring the plug insulator, explaining why the temperature is much higher. Consistency is the name of the game as any test engineer will tell you.

It appears that I haven't fixed the oil tank cap leak - maybe the gasket is not thick enough. I think it is better as the oil wasn't in the toolbox this time, but we have not solved that one yet!

And as the day drew to a close, I was left wondering how many of the Strumpshaw Ten Commandments might apply to riders of Square Fours...

Still Shaking

The summer is coming, the days are warming up and we need to get happy with the Square Four. Regular readers will know that it's overheated the carburetter and the chain is rubbing on the lower chain guard, but I have also noticed that the steering has been a little wayward - wayward in a 'I want to turn right' sort of way.

Having fitted the carburetter insulating gasket, it is time for another run out, this time to Aylsham M&S ostensibly to buy some rum. Initially we can see that the rear brake seems to be OK, while the front still needs some bedding in. The chain is still thrashing the chainguard.

Out in the country

Aylsham M&S, stopping for fuel

After a 12 mile run down to Aylsham we stopped for rum & fuel. I was delighted to find that I could comfortably put my hand on the carburetter float bowl - no boiling fuel here today and no misfire on the whole run. The oil pressure had been at a steady 50 psig running and about 25 psig idling so I'm delighted with that, and there doesn't appear to be any leaks either.

However, getting home there is oil all over the oil tank and the toolbox, again. This is a problem that has been recurring over a few years and I have always just cleaned it off, pretending it was down to the duff thread in the old oil tank. This time however, you will recall that have replaced the oil tank for one with a good thread, so that excuse has gone.

A short investigation reveals no seal in the tank cap... Did I really never notice that in the 6 years I have had this bike? Easily fixed fortunately.

Looking at the wheel alignment again, after the bearings were replaced in the winter, seems to be a good approach to isolating the steering problem. A few minutes with a straight board reveals a wayward rear wheel and a few minutes with the bike's toolkit it is easily fixed.

While I was under there, I had another look at the chain run and the lower chainguard. Yet another bit of judicious bending and we are done. Now we need another road test!

Dealing with Fuel Vaporisation

As I wrote a few days ago, whilst out on a shakedown run I had put about 6 miles under the wheels of the SQ4 when the misfire appeared. Power was really down and I had to drop to third on all the hills. Forgetting what the Four can be like in hot weather I was worrying about the ignition system, but managed to crack on home - I was overtaken by a military M20 at one point, as I could only manage 20 mph.

Back home, I put the bike back in the workshop and drained the oil tank, the sump and removed the filter. Sitting by the oil tank, I could hear the fuel boiling in the float chamber, and my Infra Red thermometer revealed that the float chamber was at 80°C and the carburetter body, near the cylinder hear flange was over 100°C - and remember, I had already spent 15 minutes draining the oil at this point.

I was clearly going to need the carburetter heat insulator that I bought a while back (in 2015!), which I had not fitted since I had the distributor the wrong way around - with the square 'condenser bulge' forward. This reduces the space available for the carburetter/spacer combination.

You'll see from the picture that there is very little room for the spacer before the carburetter hits the distributor, even with the bulge facing to the rear.

Pulling off the carburetter, it is immediately obvious that the existing, original studs barely have enough thread to allow a full nut to be used to retain the carburetter, so there is no chance of a spacer fitting in there as well:

Fortunately I have some 5/16" 303 stainless round bar knocking about, so we can make some longer studs. Here goes:

I've made them 1/4" long than stock. At this point I realised that whilst I have 5/16" BSW taps, I have no die. Now there will be a short pause...

RDG produced a suitable die, two days later:

Using the tailstock die holder made short work of the studs, but one of them has a CEI section which is a little longer than it wants to be I think:

Trying the carburetter in place, an unforeseen foul condition is revealed when the BiStarter hits one of the tank mounting bolts:

As expected, one of the studs is marginally too long in the CEI section:

There is still a few millimetres spare before the float bowl contacts the distributer:

So that's it. Stud adjusted, the carburetter goes on nicely with the 3 mm phenolic spacer, a paper gasket and some Threebond. The rear offside tank bolt has to go in afterwards.

Preliminary results show that it is pretty effective. Warming the bike up after the work, at rest, reveals the following temperature readings with the engine running:

• 162°C on the fins near No.2 spark plug
• 107°C on the inlet manifold flange - near the offside carburetter stud
• 39°C on the carburetter flange, 1/2" from the 107°C measuring point but on the other side of the phenolic spacer. That's a 68°C differential across the spacer.
• 22°C on the float bowl.

Whilst this looks encouraging, we must remember that this is a result of conducted and radiated energy - any convected heat is going upward towards the tank, not rearward toward the carburetter ; a 10 minute warm up is not a valid representation of 25 miles in a 25°C ambient at 70 mph, and we are not at full operating temperature yet.

But it's encouraging nonetheless.

Shaking Down the SQ4

A beautiful day and a bunch of spare time - the opportunity I have been waiting for to sort out the remaining SQ4 jobs and shake it down ready for the summer.

First off, check the oil in the primary case, which is all OK; the primary chain is suitably tight as well. Next, add 200 cc of SAE 30 to the fork leg we repaired, then tyre pressures, fuel and oil levels and then finally get out on it to warm it up for the oil change. A trip along the coast road on a hot day reveals that the rear chain is still rubbing on the lower guard, and after six miles of caravans & Bank Holiday tootlers the rear brake starts to feel unusual - a kind of vibration through the pedal. I was approaching Salthouse at the time, and I decided that this was only a shakedown run and that I ought to turn back. On a hot day, I reasoned, the oil will be hot enough to change after 12-13 miles.

Salthouse Village Green

That was when it all started to go wrong. I managed to follow a bus and two caravans out of Salthouse, and by the time I had put another mile under the wheels the misfire had appeared. Power was really down and I had to drop to third on all the hills. Forgetting what the Four can be like in hot weather I was worrying about the ignition system, but managed to crack on home - I was overtaken by a military M20 at one point, as I could only manage 20 mph. At least my newly refurbished speedo was working perfectly, as was the charging system. Oil pressure was over 50 psi all through the trip - dropping to 25 psi on tickover which I was very pleased with, but remember it is still running Penrite Shelsley Heavy 40W-70.

Back home, I put the bike back in the workshop and drained the oil tank, the sump and removed the filter. Sitting by the oil tank, I could hear the fuel boiling in the float chamber, and my Infra Red thermometer revealed that the float chamber was at 80°C and the carburetter body, near the cylinder head flange was over 100°C - and remember, I had already spent 15 minutes draining the oil at this point.

So, I must fit that Phenolic spacer and maybe a carburetter heat shield. There is probably enough room for about 4-6 mm of phenolic - I have some 3 mm Phenolic sheet at the minute. I may have to change the carburetter mounting studs but I think I will test out the spacer with half-nuts before I go to the bother of making new studs.

Looking briefly at the brakes, I probably have the rear nipped up too tight; the drum was smoking hot. The front had a bit more play when I got back and was working normally showing no signs of overheating. I will remove the rear wheel in a day or two.

So, after cleaning up the mess, I proceeded to remove the oil tank to exchange it for one with a good filler neck thread. I'll repair the old one in due course. All nice and tidy in there:

Look no oil tank

Fitting the new tank reminded me what a tight fit they are. My old tank had a relieved area under the frame tube, so I recreated this with a panel beater:

Next, having spent an hour winkling it into place, I remembered that the gearbox top nut has to be removed to get enough clearance to allow the bottom mount back into place. All fixed and back together now.

This year I will be mostly using... Penrite Shelsley Medium 25W/70:

Boots

Riding my W/NG around the yard the other day, wearing completely inappropriate clothing was quite enjoyable - sun out, gloves off etc. Getting home I noticed a bit of damage to the elastic sides on my old RM Williams boots:

I realized they were chafing on the end of the clutch cable end, which has no boot. Since this is a 1942 bike, it should have a rubber boot over the whole clutch arm:

Here's one I bought on eBay:

These are not too tricky to fit, but fitting will surely let you know whether the boot you have is a good quality one by splitting when you draw it back over the clutch arm. First, remove the clutch cable and slip the boot over the arm. Then, push the small end of the open end of the arm, exposing the slot where the cable fits like this:

Put the cable nipple back in the slot, and you can winkle the rubber back over the nipple, covering it completely:

Another evening run

Another evening run out around Norfolk, some shots from me but most taken and tweaked by John Harris. Find John at https://www.facebook.com/JohnHarrisPhotographyandTours/.

This week, we took a tour around RAF Matlaske, RAF Oulton and the National Trust's first property at Blickling Hall.

Another lathe job

I made a trip out the other day, with a mate on an MT350, to look at the Dome Trainer at RAF Langham. Great run out, lovely weather and all that, some shots from me but most taken and tweaked by John Harris. Find John at https://www.facebook.com/JohnHarrisPhotographyandTours/.

Back home I found the clamp screw from my float bowl had disappeared - mainly because I had changed the cap for a better one, with a tickler of the correct length to reach the float (!) and hadn't screwed the clamp up at all...

So, unable to find one on eBay and too mean to buy one from Amal (they are over a tenner!), I checked the thread and found it to be 1/4" BSF. Rooting about in the 1/4" screw box, I found an Ariel clutch centre screw which has the correct thread AND the reduced hex head, or something like it, that the real Amal screw has. Adding a small sleeve out of a bit of round bar yielded something that will do the job:

Here it is in place, with the new float chamber lid:

It will do the job until I can find a real one at a reasonable price.

Tommy Bars

Genuine Ariel tommy bars are another rare item, and typically (of the tools at least) are rather confusing - not helped by the aforementioned rarity:

• 6612-27, Dwg # G1/57 appears in the 1940 singles parts books as a single diameter bar 
• The W/NG workshop manual shows a dual diameter bar
• 6612-27, Dwg # G1/57 (yes, the same part number) appears in the 1947 singles parts books as a bar with three diameters. This also appears in several parts books until 1956, so we can assume this tommy bar was now considered a mature design (!)
• the 1948-1949 twins parts book
• the 1949 SQ4 parts book
• the 1953 singles parts book
• the 1954 Huntmaster parts book
• The 1956 Huntmaster parts book lists a 'Tyre Lever and Tommy Bar", 6625-55. Parts books (prior to Leader/Arrow) ceased to be illustrated in 1951, so we have no idea what this looks like.
• Leader/Arrow parts list include tube spanners with tommy-bar holes, but no tommy bar. One assumes that you were intended to use the screwdriver as a tommy bar...

Once again courtesy of a few members of the Ariel clubs around the world, I have these pictures of three examples of the later 6612-27 three-diameter, two step tommy bar, and a W/NG tommy bar from Ray Tolman's genuine W/NG tool kit which has yielded so much interesting information.

Part of Scott Williamson's 1949 SQ4 tool kit

Close up of some of the tools from David Andersen's 1949 VH toolkit

We can see a few interesting points from this last picture:

• the tommy bar appears to be about 0.375" in diameter and is overall about 7 1/2" long
• the tommy bar has a section reduced to maybe 5/16", and this is about an inch long. This is to pass through the holes in the various box/tube spanners and the QD wheel nut spanner.
• the tommy bar has a further section reduced to maybe 1/4", and this is possibly 3/8" long. This is to engage with the smaller box spanners and the hole in the telescopic fork wheel spindle: this is probably the reason this third, smaller diameter was introduced

Ray's pictures give us some proper information. Ray kindly measured these for me and allowed me to share the pictures so we can all use the information.

You'll notice Ray's tommy bars are a little shorter than David Andersen's later tommy bar. Here's a close up of the stepped ends; Ray confirmed that there is a 0.31" section on both bars:

I'm planning to turn each of these up from EN16 steel round bar. First cut two 7" lengths from a bit of 3/8" round bar:

Face and round the ends:

And as if by magic, some tommy bars appear:

Hub Bearing Locking Ring Spanner

This is a rare item indeed, but courtesy of a few members of the Ariel clubs around the world, I have these pictures. I've been using this modern version:

It's mostly fine, but you have to remove that handle to remove the non-brake side retaining ring since it is recessed in the hub and you cannot get the pins (which are 5/32" diameter, by the way, and about as long) to engage safely in the ring.

Recessed locking ring

The one on the brake side is easy - its not recessed at all. Making a replica of the original will make it easier to get the non-brake side locking ring screwed in, as well as completing the tool kit.

We can see from this next picture that the original locking ring spanner is cast. I'm not going to be able to emulate that - I will be making one on the lathe, welding and using the pillar drill. We can see that the disc is not much thicker than one of the pins - the pin diameter is of course dictated by the holes in the locking ring.

Part of Scott Williamson's 1949 SQ4 tool kit

We can see from this picture that the drive pins on the locking ring are very close to the edge of the disc:

Part of David Andersen's 1949 VH tool kit

Close up of David Andersen's tools

We can see a few interesting points from this last picture:

• the lock ring spanner is about 1.75" in diameter
• the lock ring spanner has a 0.820" hex - 7/16" BSF by scaling from the picture which will match the hub nut tube spanner

So, the plan is to find a suitable bit of hex bar; then use a slice of 1 3/4" round bar or a bit of 3/16" plate (which I have in stock). I've been thinking about how to make this and I've come up with the following sequence, which will probably get modified as I think more about it:

1. Cut a rough shape from the 3/16" plate, suitable to fit in the 3 jaw chuck
2. Fit the external jaws to the chuck, chuck the plate and face one side with a minimal cut.
3. Flip the plate in the chuck and face the other side.
4. Centre drill, drill 6 mm, open out to 10 mm and then 13 mm. Bevel the hole slightly.
5. With the plate still in the lathe, mark off the PCD of the pin holes.
6. Chuck the 0.820" bar and face off.
7. Turn a journal to an interference fit for the 13 mm hole and to a length equivalent to the thickness of the plate.
8. Bevel side first, push the plate onto the journal using the tailstock to keep it square.
9. Saw the 0.820" bar to a suitable length - about 0.5"
10. Put the hex in the vice with the flat side of the plate upward
11. Weld the plate to the journal
12. Put the hex back in the 3 jaw and turn the face flat again, dressing the weld
13. Turn the plate to a suitable diameter
14. Round the side of the plate with the hex
15. Ensure the PCD of the pin holes is still clearly marked.
16. Flip the plate in the chuck and face off the hex; bevel the edges.
17. Drill the pin holes somehow... ideally indexing in the lathe and using a tailstock drill?
18. Use the tailstock chuck to push the pins in square
19. Test
20. Paint

Step one, saw out the plate:

Almost there

Step two, change the jaws of the 3-jaw chuck for the external jaws, and chuck the plate. Then clean up the face with a minimal cut:

Step 4, centre drill the plate:

Next step, drilling the hole 6 mm, then opening out to 10 mm and then 13 mm. I managed to stall the lathe for the first time!

The plate prepared for welding, and the hex cut to length to go in the lathe. The 0.800" hex does not fit through the chuck...

Step 6 done, and the beginning of Step 7: turning a journal for the plate to fit on.

Step 8, the two parts together:

Step 11, welding. Remembering that the only hex bar available is EN1A, it's no surprise that the weld is porous. I'm not sure what the plate is, but that is probably EN1A as well...

Step 12, facing off shows the porosity nicely...

Step 13, turning the plate to a suitable diameter - part way through:

Marking the pin pitch circle diameter:

Ready for drilling:

Some of those voids are actually in the 1/4" plate. Great quality steel...

Dykem applied, ready for marking out:

Before we start machining the holes, we have to set the lathe up for milling. this involves removing the compound slide, bolting down the adapter plate and fixing the vertical milling slide to the adapter plate.

Before we start, we have to make sure the milling vice is perpendicular to the spindle axis. We can do this with a piece of round bar in the chuck, and a small square to set the vice up to the axis.

To drill the six holes at 60 degrees to each other, we need to index the disc. I'm indexing on the hex, welded to the back of the disc - I machine one hole to 5/32" deep, index, then machine the next.

When I've drilled all the holes, I cleaned up the disc with emery. The pins are 4 mm dowel, which provides a slight interference fit on the holes in the disc which are drilled 5/32" (about 3.96 mm) - they are pressed in place in the vice with Loctite 243 (medium strength threadlock - not very appropriate):

The holes in the hub locking rings are flat-bottomed. To provide maximum engagement, I ground the ends of the pins flat:

Next job is to turn the tool to the proper diameter, but first I need to test it:

It's not too bad, but a quick test reveals that I must deburr the pins.

Now finished. The hexagon and the disc have been turned to shape to mimic the cast original, and I have deburred the pins.