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.

FH - over one hundred miles

Four days later and we are now over one hundred miles - there hasn't been any more smoke, and I have checked the points again which seem to be stable at 12 thou. I've backed the front brake off a notch and tightened up the back on the cable - they seem to be fine now, though the pedal is a little lower than I would like.

There's some oil mist on the drive side which appears as oil when the bike is on the sidestand - it drips from the head joint onto the primary case, though there are no other oil leaks. The head is going to have to be tightened down.

In other news, a mail to the splendid AOMCC gearbox man revealed that the kickstart was an after market one - it was harassing the back of my leg. In this picture, the one without the rubber fitted is the splendid new club one - you can see it is much less cranked:

It's a lot more comfortable when fitted.

As mentioned in the last post, I moved the gear lever up a notch only to find that it fouls the timing cover. The gearbox man confirmed it's the right one, so perhaps I well drop the footrest a bit lower to put my toe in the right place.

 Riding today I heard a groan from the drive side - getting home revealed the primary chain was too tight and the rear chain too loose - easily adjusted. I'm sure the steering head could do with a bit less clearance too, though the judder from a few days ago is now a barely perceptible click.

FH - another few miles

 Out and about on the Huntmaster again today shows that the steering head bearings are getting sorted. The handling is as good as ever, maybe a bit more sure on its feet and braking is very smooth - there is much less judder from the front forks - though it does need a little more adjustment. 

Yesterday I checked the contact points and found in both positions that there was a dragging fit on a 12 thou feeler gauge. The bike started readily as usual this morning and ran very well on a 4 mile trip to Cromer.

There is conspicuous oil in the drive side silencer however I didn't notice any smoke. Is this a temporary problem that comes from leaning the bike over and dripping oil into one of the valve guides? Certainly it happens after parking on the side stand and of course the side stand causes the bike to lean towards the drive side. The oil in the exhaust could have come from the various smoke experiences I've had over the last few days. Am I clutching at straws? Is it just the rings bedding in?

The handlebar mirror is a little bit loose and needs nipping up, and the centre stand needs some oil on the pivots. Oh, and before I go, the gear lever needs to come up a notch!

FH - steering head bearings

After the last trip, back in the workshop, a quick check revealed the expected loosened head bearings - wheeling the bike forwards and putting the brake on reveals a 'jolt' from the headstock which you can hear. To check them more physically, put the bike on the centre stand and put your thumb here in the dim & dark recesses of the top yoke, across the gap between the dust cover and the headstock:

With your other hand, grasp the front wheel and rock the bike backwards. This has the effect of pushing the steering column up through the headstock against the weight of the bike, and your thumb will be able to feel any movement. Don't vigorously rock it backwards & forwards - you don't want it rolling off the stand.

Mr. Waller suggests lifting the weight off the front wheel to perform this job, bit since the Square Four is on the bike lift I use the method described above.

So, having found some movement we need to sort out the problem. First slacken off the lock nut under the top yoke with your head race spanner; Clay at Acme Stainless has these, but you can also pick original ones up on eBay. 

This time, I had to loosen the handlebar clamp to get enough access to the stem nuts. Be very careful not to damage the paint on the tank - make sure the spanner fits well (so that the spanner doesn't slip) and that the tank is protected (for when the spanner slips):

Now, grasping the wheel again, roll the bike backwards against the centre stand whilst attempting to tighten the lower of the two nuts. You will find that the nut is now loose and can be tightened down - you will want to perform this feat of coordination two or three times.

When you are happy that the bearings are snug, and you can feel no more movement, tighten down the top nut. Move the handlebars and satisfy yourself that they are not binding anywhere. 

If you use your steering damper, reset it and you are good to go.

FH - more tinkering?

 Another little ride out today - twenty miles around the local countryside:

Starting easily, it's running a lot less busily with it's raised gearing.

The brakes are feeling much better now - there's quite a lot of travel but they are certainly biting.

The steering head bearings are very loose - there's a lot of juddering on braking. There might be an oil leak from the cylinder head area - there's a drip on the front of the top of the primary case, coming from the barrel, and there's some oil at the back of the barrel.

It seems to be quite smoky on the drive side - I'll keep an eye on this.

Everything else seems to be working well though I think I can hear the ignition hardening up again so perhaps those points are closing up.

All in all though - lovely!