Shields Up, Mr. Scott...

In the everlasting challenge to keep heat away from my carburetter, I have added a heat shield to the previous insulating gasket.

I know from test rides that the radiated heat from the engine is as significant as the conducted heat, so I have attempted to deal with that with a stainless steel heat shield, mounted on the front float bowl screw. Petrol boils at 95 C, and we have seen temperatures in that region on the float bowl - and we have heard the fuel boiling. So, with some spare time and in 'metal working mode', here it is:

It's bent up from a piece of 0.9 mm stainless steel I had knocking about in the shop, cut to shape with snips:

This notch is to clear the starter jet on the front of the float bowl:

Here it is in position:

It's only mounted at the top, so we should expect some vibration and potentially a fatigue failure. We'll see how effective it is tomorrow.

Oh, and by the way if you are wondering why it says 'Meyer' on the side, have a look in your kitchen cupboards. It's the bottom of a stainless steel casserole. Waste not want not!

False Alarm

Well, thankfully the dribble of oil, grease or other shiny substance appearing at the edge of my brake drum appears to be tiny, and dry.

Pulling the brake apart took me fifteen minutes, thanks to the front stand, a wonderful invention - not only because it lifts the wheel off the ground, but also because it stops the headstock swinging about.

So easy to use...

This is the leading shoe, a little high in the middle - maybe about 60-70% contact:

Leading shoe wear

And this is the trailing shoe, wearing as you would expect - a little more than 50% contact:

Trailing shoe wear

So, we have something like 60% contact overall. A little relief on the high spots should help tremendously, which I can do with some 60 grit paper and a file.

As for the grease, just a little dribble. We will clean that up tomorrow.

And there is a lucky eBay find on the way!

For those fortunate enough to be less geeky than me, this is an original Ariel brake fulcrum spanner. Very rare. Here it is in action:

Trip to the Seaside

After an uneventful run up to Sheringham, North Norfolk.

This may not seem much, as a 27 mile trip, but its the first time that I have been out riding on a route that was not circular around my home - the idea being that as you shake the bike down the radius gets larger. The first trip I do on a rebuilt machine goes out of the gate and I turn left and keep turning left until I get back, 10 minutes later. I increase the radius of the circular route as I get more confident with the machine.

As you all know, I have been having overheating problems leading to low oil pressure; as many people have said, Mk1 engines run very hot when newly built - at the end of this trip, the SQ4 had clocked up 117 miles since rebuild. 

So, following your advice, I am breaking it in slowly and keeping an eye on the oil pressure. I'll run it around each day and build up some miles.

Valve Timing

So, we had another nice little run out yesterday, on a shopping errand this time. No dramas, Amelia running nicely with her new brake shoes. She attracted some attention from a cyclist who came over exclaiming: "Oh, a Squariel! I haven't seen one of those in years!" He proceeded to tell me about his Triumph TSS and T120R, which apparently was fitted with a Morgo pump as well.

You meet the nicest people on an Ariel.

I'd heard mention of the effect valve timing has on overheating, and it occurred to me that in the joyous response to the problems I had had setting up the valve timing initially I had possibly not been too careful to get it spot on, being happy to go with the factory timing marks. Ariel folk lore tells us this is not wise.

So, when I arrived back from shopping I whipped off the offside rocker cover, the #1 plug and the front crankshaft cap and had a look - and it looked like number one inlet valve was opening near TDC - it is supposed to be 3/16" before TDC.

So, late in the night, and with the head torch on I took off the timing cover. I discovered that if you remove the dynamo sprocket you can reset the valve timing without removing the camshaft sprocket (and hence you can leave the oil pump in place too) After 4 or five attempts I finally got the timing as close as I could - which I think is spot-on. The cam chain tension makes a big difference, and you have to test it with tension on the cam chain.

I may need to change the cam chain at some point - a worn chain affects the valve timing.

So that done, I reset the ignition timing, a job which is very easy in the dark, because you can see when the points open if you turn the ignition on, since there is always a little spark when the points open. However, testing it all again the next day revealed the valve timing was indeed spot-on, but the ignition timing was way to far advanced, as evidenced by several kick-backs and spitting at the carburettor. Realising what these symptoms meant, I reset the points gap and the ignition timing again.

And after all that, as usual, she starts easily; but probably more easily than ever; she runs eagerly (though I could only manage a couple of miles) and she idles very much more smoothly.

We have some errands tomorrow; we will see what happens on a longer run

17 mile test run; fun with brakes

Lovely test run out to Bawburgh today, about 17 miles around the countryside. Bike is definitely running less hot, since after 8 miles I still had maybe 25 psi oil pressure at 30 mph, but that was dropping to 10 psi on the gauge at the end of the trip. I measured the oil temperature - 95 degrees C in the tank (about 200 F), which is much higher than I have seen after, say, a 5 mile trip.

As you can see the bike is on the sidestand - what I noticed later was that the carburettor drips fuel onto the dynamo in this position. I had left the fuel on though. 

The engine sounds happy enough; I'm not too sure about this gauge - I keep wondering how I would feel if it had never been fitted. I'm tempted to buy one of the club reproduction gauges, or to get this one calibrated.

Out on the road though, the Ariel was handling fine for the first few miles until I became aware of a juddering from the front end, which I initially put down to the road surface. On braking however I found no movement in the front brake lever, and realised the brake was seizing on. Near home, I stopped for traffic lights and saw smoke coming from the front brake (I've been here before, with the Bantam)...

Arriving back I was greeted with grease everywhere. As we all know, hot brakes cause the grease in your hubs to melt...

Stripping the brake down revealed some serious damage to the linings, and bits of lining (2-3 mm bits) all over the drum. The linings you see in the pictures are greasy, but those matt grooves in the middle are way below the wearing surface:

Greasy

Cratered Lining

Now, I don't know if this is a result of heat, or the heat is a result of this breaking down. I'll take it back to the supplier tomorrow and see what they say.

Odd, since it had been bedding in nicely and getting quite effective.