FH - back in action

 With the Square Four on the bench, the Huntmaster fixed and a trip for a job in Cromer in the offing it's time for a little bike ride. 

In preparation, I topped up the oil a couple of days ago as I had had the return system apart and expected the filter to be empty. I turned the engine over on the kickstarter with the plugs out in order to prove circulation before I used it again. 

After I'd finished my decorating job, I came back to the bike to find a little puddle under the rear chain case. I guessed there might be too much oil in the oil tank and so it proved: 

I filled the big syringe twice getting this back to an acceptable level. It's been off the road for a couple of weeks and obviously wet sumps! 

At the same time I adjusted the front brake and the head race bearings.

SQ4 - changing the oil

 It's high time Square Four had an oil and filter change, so with the oil return line repair complete on the Huntmaster the Square Four is back on the bench after a 10-minute run to warm the engine oil up. 

As usual it's an absolute pig to get the oil tank out but it's very easy to drain the tank and the sump - I have a new sump plate (well, it was new 10 years ago) with a drain bolt and magnet in the middle of it. I had something like 300 ml of oil out of the sump - I'm not sure whether that's unusual or not. 

I was surprised to find the sump strainer damaged - I think I'll get a new one from Draganfly. 

With the oil tank out I can degrease the area around the top of the box where the filler is - it's always quite mucky around here because it's very difficult to top the box up without getting grease everywhere.

The oil tank is also a very tight fit - it's always a struggle to get it out. I'm wondering if it's fouling the the frame tube, perhaps stuck between the frame tube and the gearbox plates.

I had the tank in the parts washer for 15 minutes washing the outside and the inside and was pleased to find very little sludge and no debris in the tank at all. There's obviously been some further washing of the engine through the detergent oil that I'm currently using as the cases appear very clean and the goo in the bottom of the tank and on the sump of drain plug is just like the dark grey substance you would get from the crankshaft sludge traps.

You can see one of the cams in this picture - the wear ridge is quite clear. I have a new camshaft ready to go in when I decide that I'm bored enough to rebuild the engine!

I filled in my maintenance spreadsheet but for the record the mileage is 4089 miles.

FH - chasing leaks

 This is the engine to oil filter pipe on leak test. No holes there!

However, this one is the oil filter to oil tank line:

So there's a nice leak there. The next step is to rework the oil line arrangement to the filter which I will do using a slightly different route between filter and tank since I think a contributing factor to this failure has been that the oil line has exceeded its minimum bend radius.

Charlie's Shed - chemical blacking

It's a fasteners that I've been making for the Model A are all turned from mild steel - there is no stainless on the bike at all. The plan is to use some gun blue or chemical blacking to reproduce the iron oxide finish from the original fasteners, called 'coslettising'. As an experiment I have used this product on the Huntmaster's oil filter bolt:

 Since I made it some years ago I have modified it to provide greater engagement of the thread. After turning I degreased it and suspended it in the cold blue for about 5 minutes followed by a rub over with linseed oil.

FH - finding weak spots

 Another local trip on the FH, and another 8 miles on the clock. Unfortunately it's perfect record is blemished by a puddle in the yard when we arrive home. This continues as long as the engine runs and stops eventually after we earth the magneto. Starting the engine again the next day shows the puddle begin again in earnest:

Poking about underneath suggests that this oil is coming from the engine to filter oil line which loops around the bottom of the gearbox. It looks very much like the hose has split, perhaps because the line is bent beyond its minimum bend radius. 

We'll have to remove the battery to improve access to this area and decide what to do. I used BSA A10 oil lines for both the return connections and I know that one of these was a little bit too long. I think what I'll do now is get some bespoke oil lines made up that fit properly.

Maybe I'll swap the FH and the Square Four around on the bench, clean the Square Four with the new sprayer and use that until the FH is fixed.

Incidentally, before the Square Four came off the bench I discovered that the oil filter was a bit looser than I would have liked. Perhaps that is responsible for some of the oily mess under the engine.

SQ4 - a bit of maintenance and a good clean

 Now that I've finished installing the electronic ignition and the FH is doing sterling service as the daily rider, it's time for the grubby old Mk1 to get some attention. Looking at the maintenance schedule shown here, there's a few bits that need attention not least an oil & filter change with a tank washout.

My U-Pol degreaser works wonders on the back wheel:

The next step is to lift the fuel tank and clean the cylinder head.

SQ4 - updating the ignition system

 The Square Four is on the bench at the moment for some maintenance and an electronic ignition conversion. 

I'm fitting an Accuspark system to see what advantages I can really gain. I'm led to believe that the bike will start more easily and will be smoother - I'm hoping that it may be slightly less rattly particularly in the coupling gears and I've also been told that running in town is better as the Hall effect sensor is less sensitive to the low voltage the dynamo provides at low speeds.

This is what you get in the kit - a new distributor base with the Hall effect sensor and 3 magnetic sleeves to go over the distributor cam. I understand that they are all the same magnetically but you use the one that fits best.

Here's the old setup - it works perfectly and is original. Starting is very easy so it will be interesting to see what I gain, if anything. I don't have to change anything permanently here: I can retrofit this system easily if I want to - I won't be cutting or removing any wires

There's two things to check in the battery box - one that it really is negative earth and two that I have removed the fuse to isolate the battery.

This is a useful view of the current cam and auto advance setup - you'll notice the odd springs. I don't think they're supposed to be like that but it's curious that I have a single spare spring in my box of ignition parts. Anyway, the second thing is that those rivets are raised compared to the body of the distributor and will foul the base plate of the new electronic ignition sensor so there is some work to do to provide clearance.

I've measured the diameter of the circle described by the rivets and marked it out on the base plate using a pair of odd-leg callipers, ready to cut a hole.

The base plate is actually quite thick - probably 2 mm or so. Since I can't find my Abrafile I have chain drilled inside the circle and will have to file it out. The housing is made from sheet steel set into thermosetting plastic and we don't want to crack it using some over-brutal method.

So that's it filed out quite neatly but we don't want to be too self-congratulatory at the moment do we! The problem is not obvious but actually it is not only the rivets in that ignition cam that are proud of the distributor body mounting face - that diamond shaped piece is also verging on being too high as well. I toyed with the idea of reducing the height of the whole cam assembly for a while but the real solution is to open the hole out again.

And as if by magic here it is, opened out to 40 mm. The difficulty that arises now is that the two M3 mounting holes for the sensor are very close to the edge of the hole and in one case the hole is no longer complete so I'll have to think of some other method.

The sensor was originally mounted on a little brass plate so what I've done is used that brass plate and the existing holes in the steel base plate to position a much larger brass plate that bridges the 40 mm hole in the base plate. I made the brass plate much too large but roughly the right shape and drilled for the two M3 holes for the sensor, fixing the brass plate into place on the base plate through the sensor holes. I then drilled two more holes outside of the large central 40 mm hole and fixed the new brass plate with two additional M3 screws. That way I could guarantee that the sensor would remain in its original position.

And here it is fitting nicely. The three rotating magnets are quite different shapes internally, and only one fits this cam - and it fits firmly.

And again we have the rotor arm in place and the distributor base plate screwed down.

I've temporarily wired it up for the moment - the red wire goes to the positive feed on the coil and the black wire goes to the contact breaker side of the coil. It will need some PVC tubing over the wires and some better quality eyelets, and I'm waiting for some thermal paste to use with the sensor and the brass plate but it will do for the purposes of testing. 

Hopefully I will get an opportunity in the next day or two to start the engine.

Post script: I started the engine on the 13th May, loosening off the distributor and retarding the timing to get it going; the Hall Effect sensor made an odd buzzing or fizzing sound which made me switch off in a hurry to check the wiring. The wiring was fine; the sensor wasn't tight enough on the baseplate which seemed to improve matters. It's still doing it and it sounds thermal. With the engine warm I advanced the timing to more or less where it had been before and went for a test ride. It's certainly smoother.