FH - preparing the primary drive

There are a lot of work faces appearing on the bike now the cylinder head is ready to go on; the timing side can be assembled once the automatic timing device is finished and the primary side can have the clutch fitted and the primary chain built up. For no particular reason I've elected to start on the primary side mainly because I don't have the bench space at the moment to do the ATC. Here I've fitted the 19 tooth standard gearbox sprocket with a spare secondary chain and torqued up the big nut.

 

The spare length of chain I had knocking about was too short so I've taken this unusual approach of wiring it through the holes in the sprocket just to allow me to use the back brake to tighten up the gearbox sprocket nut.

With that done we can start looking at fitting the inner primary case half. What's different about this bike is that it's fitted with the fully enclosed rear chain case (FERC) something I have not yet experienced on an Ariel. There are a couple of unusual mounting points, one of which is this nut which is attached to the front half of the FERC.

It's a 1/4 in CEI bolt which needs a special tab washer to retain it to the inner primary chain case casting and to prevent it coming undone, dropping into your primary drive. The special lock washer is available from Draganfly but unfortunately I forgot to order one. I've made this one out of a piece of 0.9 mm sheet steel.

Here it is with the bolt tight and the tab washer folded up.

For the record I have fitted that 1/4" BSW screw with low strength threadlock from Loctite. The castellated nut retaining the engine shaft shock absorber will need a split pin to prevent it falling off.

That's it for now; the next step will be to think about the clutch. I expect to find some parts that are in need of replacement so I'll have a look at the clutch soon to get those on order.

For now, let's just record that I fitted a new length of primary chain and an old spring link just for now. I'll have to order a new one. 

The other thing to bear in mind is that the chainwheel is rubbing on the oil catcher so I'll have to sort that out before I put primary case outer cover on.

FH - cam followers

After a 60 mile round trip on the Square Four which left me worrying about its coupling gears I decided to have another look at the cam followers in the Huntmaster. I had refinished the wearing surfaces to true them up but I knew that one of the followers had worn through the case hardening. I decided to stop messing about and get some replacement followers.

These are available as an exchange part from Draganfly Motorcycles and they came very quickly, in a couple of days. Refitting is very simple and I replaced the barrel with a layer of Wellseal on the gasket.

Before I did this however I wanted to make sure that the cams were going to be properly lubricated on startup so I used my oil can to make sure the channel under the camshaft was full of oil as you can see in the picture below.

With the barrel fitted, I could oil the followers from above:

I threw the pushrods in to start understanding how difficult they would be to fit. I once spent ages chasing a valve timing problem on the Square Four only to find that I had the pushrods in the wrong followers!

FH - rocker box refurbishment

With the cylinder head coming on, it’s time to take a look at the rocker box. We won’t be doing too much, as a number of folk have told me how a BSA A10 rocker box fits straight on and is a much better design - but I don’t have one of those.

We’ll start by stripping out the rocker shafts and cleaning the box.

While the lathe is in action, we’ll replace the 5/16" BSW stud that wasn’t holding the cover on - the covers are held on with a special 1/4" CEI sleeve nut. What we need is a stepped stud, like the original in the inlet side but with a 5/16" BSW thread to go in the aluminium casting. Somebody has already recut the thread in the casting to suit the replacement stud.

We'll start with a bit of 5/16" mild steel round bar. Because it's 1/4" in diameter for most of its length we'll need to be careful when we turn it. What we will do is use the travelling steady on the lathe to support the slender quarter inch section as we turn it to size.

 This turns out pretty well especially when we make a finishing cut with a round nose tool. Cutting the 5/16 BSW thread, I've set the die to its largest diameter such that the thread is a little oversize.

This is where the oversized thread pays off - when it's fitted in the box the the stud fits quite tightly and hopefully won't back out.

The next step is to get the box in the cleaning tank for degreasing; we'll then examine it for damage and polish the outside.

Mini-lathe - boring bar

 

My 0XA boring bar holder fits 1/2" bars or 3/8" bars with an adapter sleeve. Shame my boring bar is 10mm! It currently resides in a 250-001 tool holder, which is a bit of a waste.

Mini-lathe to the rescue! The sleeve on the left is turned from a bit of 1/2" round bar, with a 10mm reamed hole and a slit. Works perfectly, and liberates another 250-001 tool holder!

SQ4 - fuel tank

 Some years ago the Square Four got a new fuel tank in original paint from Yeoman’s Motorcycles. It was pretty shabby but it still had the coach lines picked out in gold paint to show where the Ariel craftsmen put them all those years ago.

As you can see the paint is very faded. The Square Four wore this tank for several years but eventually I decided that it was really too far gone. I didn’t really want to repaint the whole tank and lose all the patina, so inspired by Graham Ham’s book about his Speed Twin ‘Daisy’ I resolved to clean up the paint as best I could and enhance the gold lines a little bit.

The areas that were worse affected were around too weld repairs where the tank badge carriers had been refitted. The paint here was burnt and discoloured and no amount of rubbing down was going to bring that back. I used a matching spray paint (from stock I had accumulated years ago) to blend these areas in to the rest of the paint. Rubbing all the paint back with various grades of wet and dry from 240 to 2000 brought the tank back to life enough. 

I then used some old jet black gold lacquer and some 3 mm PVC masking tape to put the lines back in. When these were mostly dry I rubbed over them with a dirty glove to dull them down. This works reasonably well when I timed it correctly but if the paint was too dry it didn't pick up the dirt from my gloves.

It needs more work of course, but it's getting there for sure.