FH - more lift please

 The design of the centre stand fitted to the swinging arm bikes is one of the few weak areas of the last aerial frame design. It's not very strong - legs are often a little bent, the holes wear oval, the stops deform, and the feet drag along the ground and wear away quickly. It's easy to use but it's faults are not helped by people starting the bike on the stand. 

When restoring a frame it's one of the first things to look at. The stand stops on the frame are likely to be deformed and you want to build them up with weld before you paint the frame. Feet are readily available from Draganfly for you to repair your own stand, and Draganfly have replacement centre stands if you don't fancy doing the welding.

Geometrically then, it's a pretty good design let down by details. The stops aren't big enough, and the single sided foot pressings are just... bad.

Stand repair is something I don't look forward to, or didn't until someone came up with a new method. Personally I've never had much success trying to lever the stand around to get the pins in, and I've hitherto resorted to the old method of pushing pennies, washers or wire into the open coils to get the springs off.

Until this method came along. Setting the scene: the bike is on a scissor lift under the frame rails and the centre stand is in the raised position - I've actually got the front wheel clamped and a cargo strap holding it upright as well.

The first step is to remove the outer circlip and washer from each side - I find it easier to push the pins into the middle.

Next I've secured two cargo straps to the ramp, each one looped around one of the stand feet. If you were doing this without a ramp, you could secure the straps to something heavy in the workshop or perhaps to the rear wheel of the bike.

The next step is to put a bit of tension on the straps - it doesn't take much, just enough to let you feel the pins go loose so you can push them out.

Getting the stand back on is almost as easy. Once you have the straps around the feet and the springs in, you can tension the straps and align the stand eyes with the holes in the frame. You'll have to manoeuvre the eyes to get them to line up, but the cargo straps take the strain and allow you to get the pins inserted without having to hurry.

To repair the stops is easy - if you can weld, or know a man who can. You don't need to add much to the stops - the stand legs are about 8" long and the stops are located 1" away from the centre of the pins, so if you add 1/8" to the stop you can move the leg about 1". Depending on the angle of your stand, that will give you maybe 3/8" of lift.

These eyes appear to be steel castings - they seem to weld very easily.

Wear aside, my stand issues are partly of my own making. When I ordered the shocks, someone suggested that I opt for a bit more length in the shock to give a bit more travel at the rear. Looking back, if I had realised I would need additional lift from the centre stand to accommodate the longer shocks I don't think I would have done it.

SQ4 - all done

This might be the last post on the Square Four for a little while - it's next trip is likely to be to my long-term storage at my son's house, where I shall go to collect W/NG to come back for some work - but more on that later .

Today I took the Square on a 15 mile round trip to Cromer to do some painting and do the final shake down on the carburettor and ignition settings. Yesterday I fitted the new mixture screw and this needed a little bit of tweaking to get it spot on and I increase the idle speed slightly - though I think I've got it too high. I also retarded the ignition slightly. 

The good news is that it's running very well. It starts easily and it will pull away cleanly in traffic from low speeds. It flies along on the open road so all in all I'm very happy.

Here it is resting at Gresham church.

Getting home, it occurred to me that in a similar fashion to the light switch yesterday I had not touched the horn for a long time. Since I fitted this horn, which came straight from eBay, I don't think it's had any work done to it and as regular readers will know I've become reasonably adept at adjusting these horns.

I gave this one a little tweak to make the sound a bit more intense.

SQ4 - idle mixture screw

 I recently took a punt on an eBay sale for a mixture screw for a carburettor from a Rolls-Royce B40 engine, the one used in the Austin Champ. It was listed as a Solex part and looked very much like the one on the Square Four.

I struck lucky - the parts are exactly the same.

This is the old one, and measures 4.86 mm at the end of the thread

This is the new one, which measures 4.92 mm at the end of the thread:

So perhaps not a huge amount of wear. It does appear though that the nose of the old screw is notched - I don't know if you can see it in this picture:

I fitted the new screw with a t-bar and put it back in the carburettor with a wrap or two of PTFE tape. 

We'll have to see if it makes a difference.

SQ4 - dodgy connections

 Riding home a couple of days ago in rather poor light I became aware that the headlamp had turned itself off. A few minutes fiddling with the light switch made me realise that there was something going on with the contacts - I could wiggle the handle and the light would flash. This needed further investigation.

As far as I could tell from various blog posts, this original Lucas U39 light switch had not been apart for probably 10 years. My own skills and knowledge have improved immensely in that time and I now clean these switches with an ammonia based clock cleaning solution as shown in this post. 

The one on the bike was clearly a bit grubby. 

I stripped it out and immersed it in a 25% solution of ammonia-based clock cleaner for about 4 hours.

After a few hours, the brass parts emerge without the tarnish and looking a lot more and conductive!

Here it is again, reassembled.

Charlie's Shed - tool restoration

 I've done a lot of posts on toolkits and tool rolls in the past, and here comes one more. Repacking the Huntmaster toolkit one day I noticed that a 3/8 BSW spanner was rather damaged - in typical fashion it had been sprung open by over exertion.

It's actually quite easy to fix these. I set it up in my little hearth and heated it cherry red, picking it out with a pair of tongs and giving it some adjustment with a 1 lb hammer. It's actually closed up nicely back to size.

The black finish is achieved by quenching it in oil.

SQ4 - idling again

 A 30-minute run out this evening confirmed that adding PTFE tape to the volume screw put us on the right track to improve the idle and hesitation problems on the Square Four.

It needs more work, adjusting the idle speed down, further adjustments to the ignition timing and probably some small changes to the idle mixture as well but it is starting well and idles smoothly. 

SQ4 - idling

 The Solex is back on, but I still have a problem with idling - but it's different. The bow in the inlet flange that I removed has changed it's behaviour at idle, as you might expect, but in tuning the idle I've realised that the idle volume screw is very worn. 

I've ordered a new one:

While I wait, I've wrapped the old screw with PTFE tape which should help.

FH - A few odds and ends

 With an hour or so to spare, I went to the workshop to finish putting the tank on the Huntmaster. Bolting it down was no problem but I noticed a drip from the tap. The plunger was very loose and I imagined the cork might have dried out since it had been empty for quite a long time. I was wrong about that - the cork was just knackered. 

Fortunately I have quite a lot of spare plungers knocking about and I found one with a good cork that I could plug the tap with whilst I repaired the original. It's the usual drill here with these post -war taps - you knock out the brass centre using a punch, replace the cork with a new one, and put the centre back in. In taps where you have to twist the plunger, the centre is actually formed as a square at the outer end and there wasn't sufficient material left here to re-peen the brass end into the chrome handle. I filed the end back a little bit to give me more length and used to centre punch to peen it into place:

The next job had been coming for a while. The chrome strip which hides the welds on the top of the tank broke at the hook holding it onto the end of the tank. I toyed with the idea of buying a new one for a while and then realised as it was brass I could probably make new hook, soldering it in place of the old one. 

I made a new one and used some solder paste to tin both the strip and the new hook adding some extra solder to it once tinned.

I held it in place with some clamps whilst I sweated the joint together.

That worked really well, and is more secure than it has ever been.

Charlie's Shed - a leather tool holster

 As some of you know I volunteer on the North Norfolk Railway as a steam fireman, trainee DMU driver and trainee guard. Some of these roles need a few bits of equipment which can be bought or made. 

Some of you also know that I have a 1930 Ariel Model A which needs two toolboxes and that I have a hankering to make these myself from leather, so I've concocted a few little jobs to learn about the leather work. 

This latest one is a little holster for a ticket clipper - that old-school tool that you used to see bus conductors and railway ticket collectors using to make holes in your ticket.

We start with a bit of 2 mm leather, soaked in the sink. Add to that the ticket clipper wrapped in cling film and a wooden form cut to the shape of the clipper plus a few millimetres.

Using the clipper and that form we can squash the wet leather around the clipper until it dries and miraculously it will have formed the shape of the clipper. Behind that there is a thicker bit of leather which will make the backing and the belt loop so that I can carry this around up and down the train.

When I've cut the backing to shape I can use my stitching punches to make the holes for the stitches. This is quite hard work on the thumbs! Since I made my key wallet a few weeks ago I have learnt to stitch in a box shape in order to make the belt loops rigid.

The next step is to glue and stitch the formed shape to the backing. We will be gluing flesh side to skin side, which will never work unless we use some sandpaper to rough up the skin side. We are going to stitch this joint as well but the stitching will go more easily if we glue it first.

We use the stitching pony to hold the work firmly whilst we sit in front of a YouTube video and sew it together using the normal saddle stitch.

The final step is to use the knife to cut the waste away.

There's always a question about belt loops but this time the design fits nicely against my waist and is easy to use. I can get the clipper in and out and the holster doesn't move at all.

SQ4 - small change to the distributor

 Just a tiny but maybe significant change today - this may be a mistake particularly as I'm changing two things at once - but I have just changed one of the distributor advanced springs.

The Square Four has always had two different springs which is not uncommon and it's designed to adjust the advance curve provided by this simple mechanism.

What I've done is replace the heavy spring with another which matches the existing lighter spring. As you'll know, at the same time I have repaired and inlet flange leak on the carburettor so I am committing a crime against my own rule of changing more than one thing at a time!

In other news, the Solex is almost complete and will go back on tomorrow I expect. The Huntmaster is also done - all I have to do is put the tank back on.

SQ4 - Solex again

 Some while back I retarded the timing on the Square Four and improved starting greatly, but it is still running roughly coming off idle and when coasting. Nothing I do to the carburettor seems to improve this so I have resolved to have another look. 

Stripping off the carburettor is quite easy and another inspection revealed nothing new. However looking at the gasket faces (something which I would do every time with an Amal carburettor) revealed a bit of a surprise: 

You can see here, by the dark line along the edge of the flange that it is by no means flat, which can lead to a weakening of the mixture. A few minutes on some 200 grit wet and dry paper revealed this:

A few minutes more work improve that even further. 

The internal mating face between the throttle body and the float chamber and jet castings was nothing like as bad:

This face did show a little distortion, but it was easily removed. You will note that one of the throttle disc screws is missing - I removed that one but as you can see the other one didn't come out without a fight. The reason I removed it is revealed by this picture: 

See the light around the edges? This is ostensibly completely closed! What I needed to do therefore was to remove or loosen the butterfly screws and realign the disc so that it was properly closed. In reality it's not essential that it closes because the throttle stop is there to provide some idle speed and the butterfly will always be partially open. This kind of leakage will prevent you idling as slowly as you might want to so it pays to reduce the gap as much as possible. I replaced the screws and got a marginally better result:

I will work on this some more when the proper screws arrive. These should be raised countersunk M4 screws, around 10 mm long.

FH - coming together

 This is going to be a very short blog post and is just here to record that the top end of the Huntmaster is back together and currently waiting for the tank to go on, when it will be ready for the road again. 

As you can see I have cut the rocker box oil line and bent it out of the way of the bottom of the tank. It now sports a short length of flexible hose and some hose clips to allow the rocker box to be removed without interference from the oil line banjos. The rocker box has been on and off several times getting the gaskets right and developing the sequence of bolting up so the absence of the banjos has been useful.

FH - update from the bench

 Yes, the FH is still on the bench after I have been faffing about with the Square Four. The issue is that when I put the rocker box back on I squashed one of the studs for the head steady into its nut and damaged the thread - so the rocker box had to come off again. I decided to buy some new half nuts and reduced hex nuts to tidy up their appearance and I just got round to putting it all back together.

Of course it still takes two goes because as usual I have forgotten that you have to start the nuts for the head steady and the two reduced hex nuts at the rear due to curves in the cylinder head which prevent you getting a nut on...

SQ4 - a useful modification

 I've been fiddling about with the ignition timing this week as there had been some significant hesitation coming off-idle and some poor performance at low speed - what we used to call 'kangaroo petrol'.

I retarded the timing a bit and realised the bike had stopped kicking back on startup, and the slow running was better, and it would fly along like a bat out of hell - but coming off idle still wasn't as smooth as I'd like.

In the end, after fiddling with the idle mixture and getting nowhere, I stripped the carburettor.

I didn't find much. Some debris in the float chamber, the flange fixing to the head looser than it should have been, and one of the float chamber screws was loose. I blew out all the jets and ports with carb cleaner and found everything clear.

Putting it back together, I added this little tee to the idle mixture screw to make it easier to adjust (it's a bent bit of brazing rod, soft soldered to the brass screw), and used some Threebond on the flange.

We'll see what happens.

SQ4 - after the service

 A few little teething troubles appeared after the recent service, most notable of which was the oil pressure. Normally the oil pressure sits at 75 psi when cold and rolling at main road speeds, dropping to 25 psi idling after 15 miles or so.

Today, it was going up to 75, but intermittently dropping to 40 or so - very odd. I bled the Morgo again:

When that appeared to be happy - there were no bubbles I turned my attention to the relief valve.

See that bit of debris half way along the spring? I cleaned that out, and after a suggestion from Richard in the AOMCC, I changed the ball and reseated it.

I then rode to Cromer and back, clocking up about 13 miles - until it warmed up, it sat solidly at 75 psi and was still showing 50 psi when I got home. Back to normal.

It’s a bit snatchy at low speed. Initially I thought this was carburetion (not that I have changed anything), then perhaps transmission snatch, but all is normal there.

I’m going to retard the timing a bit.

FH - still on the bench, but looking good!

 It's been a while, or it feels like it. It's actually almost a week since I did anything to the FH - I've done a couple of railway turns and the weather has been a bit wet.

The head bolts are torqued to 32 lbs ft or so. I tightened them down using a 1/2" square ratchet (as per the manual, as tight as I could get them), then checked them with a torque wrench set to 32 lbs.ft. - so they may be tighter than that. The 32 lbs.ft seems to be bandied around a lot in connection with iron-head A10s.

This is the drive side cylinder - 140 psi or so. this was showing 75 psi on the last test, and is the cylinder that weeps oil.

This is the timing side cylinder, which showed 95 psi in the last test.

Now, obviously these numbers are a lot higher than we saw before, but don't be fooled, this is partly because I had the throttle open during the test - it was closed previously. The big win here is not the high numbers, but the fact that the two cylinders are no longer 20 psi, or around 25% different.

I bought a couple of sets of rocker box gaskets on eBay - they are identical to BSA A10 rocker box gaskets, though the tappet cover gaskets are different. I fitted these with Wellseal last time, and destroyed them lifting the rocker box. This time, I'm going to use Threebond 1215 on one side with grease on the other.

I'll have to find a moment to put it on.

FH - back to the bench

 After returning to the road following the split oil line incident, the FH has now clocked up 270 miles and it's high time to retighten the cylinder head. There are a couple of issues - it's still leaking on the drive side, and it puffs a bit of smoke from that side as well. Perhaps the return oil way is leaking oil both into the cylinder and out of the joint, onto the fins. We know from this post that there is a compression problem, and the behaviour demonstrated during the compression test supports the head gasket leak theory.

Removing the tank reveal this nasty fretting damage to the rocker oil feed pipe. Given that this pipe and it's banjos are in the way when the rocker box comes off I think I might cut the pipe here and fit a bridging rubber piece so that I can remove the banjos easily with the rocker box next time.

With the rocker box off I could get the spanners back on to the head nuts. I got quite a bit of movement on the central ones so I'm quite optimistic there will be an improvement in the compression figures for the drive side cylinder. We shall see when it's back together.

Not surprisingly perhaps but I discovered that you can't do a compression test with valves that won't open and the bike on the bench, because you can't fill the cylinders and you can't get enough purchase on the kickstart to give it a proper kick.

Never mind. While I'm under the tank I thought I'd have a look at these broken grease nipples for the steering head - this is the first time that I've successfully used an easy-out for anything!

I fitted a new one from stock, but I've only got one unfortunately...

SQ4 - back to the road

 A couple of days ago, the Square Four came off the bench to be replaced by the FH in order for me to torque down the cylinder head at 270 miles. The Square rolled easily onto the floor as it's great weight dictates with little left to do than fill the oil  and fuel tanks. 

It had been off the road for something like 4 weeks for a service and one evening I ladled in a gallon of fuel drained from the FH tank. It wasn't until I went to start the engine that I realised the fuel was pouring out of the fuel tap. It had dried out. Choosing the easy solution I soaked it in fuel overnight to see if I could get the cork to swell up again: 

This worked a bit but not well enough. The next day found me replacing the cork with a new one and also replacing the two o-rings in the reserve plunger that I made some years ago. 

Finally getting the engine started revealed another problem - no oil pressure. I ran it for 10 to 15 seconds or so with no success and shut the engine down. I realised that I would have to bleed the feed to the Morgo oil pump. I don't believe I have drained the tank before - the last time I changed the oil I didn't wash the tank out so the oil lines from tank to engine would never have been drained since I built the engine all those years ago. 

Bleeding the pump is very easy as it has a built-in hole for the purpose:

I was pleased to find the timing chest very clean and the sprockets and chain in excellent condition with the tensioner working properly. A few minutes with a screwdriver had oil seeping from the bleed hole and the whole thing sealed up again. 

Restarting the engine found the oil pressure leap up to 50 psi immediately. There is a little niggle here however in that normally the oil pressure will rise to 75 psi on startup from cold, but we do have different oil this time. I'm using Motul 20W-50 in place of the old green tin Duckhams lookalike that I used to buy from Halfords. 

Secondly the engine is not running very cleanly, misfiring a little. There may be some investigation to do.

Thread & hex data

 The following page provide descriptions of the threads in common use; the drill sizes, pitches and hex sizes associated with them, and a few interesting tit bits of information...

• Reference Page

It's handy to have it in the blog - makes it easy to find when you are in the workshop.