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Sunday, 7 September 2025

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.

Friday, 5 September 2025

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.



Thursday, 4 September 2025

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.

Tuesday, 2 September 2025

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.