Mini-lathe - shimming the saddle

 This is a job I've been intending to get around to for years.

These Chinese mini lathes have a saddle to bed clearance set by two M5 screws providing a clearance between the saddle itself and it's retaining plate. These screws are more or less on the same centre line as the bolts retaining the plates and thus the plates are never parallel to the bed and the contact between the plate and the bed is more of a line than a flat area - something you can see in one of the pictures below.

This leads to poor control of the saddle clearance to the bed which can spoil finish or make your saddle stiff to move. The fix varies - since you don't adjust this very often, I think the easiest way is to shim the plates but various people have shown other options such as a sliding wedge operated by a screw which has the advantage that you can adjust the clearance from outside without having to strip off the lathe down. 

As I said we don't do this very often so we will go with shims. The first job is to measure the thickness of the saddle accurately and this is something around 24 mm - actually 24.08 mm.

The next job is to measure the distance between the bottom of the bed and the top of the saddle which will be similar to the first measurement plus a few hundredths of a millimetre (This lathe is Chinese we will be talking in metric for this post!) 

The difference between these measurements is 24.33 - 24.08 = 0.25 mm.

I don't have any shim stock but I do have various bits of sheet. I have a chunk of oil can which is 0.025 mm thick and is easily cut with the Wiss snips. Making holes however is extremely difficult - I drilled these between a piece of wood and the saddle plate but it really needs a punch.

It turned out that I had already done the apron side but with a 0.15 mm shim - but I had left the adjusting screws in for some reason. I took them out and replaced the plate with the same shim and found that the saddle wouldn't move at all, so I put a 0.25 mm shim in and reassembled the lathe.

The saddle seems to move smoothly but not have any up and down movement - but it is very hard to tell. Perhaps I'll put a DTI on it and we'll see if we can measure movement.

Model A - Kickstart spring cover

 When you have a few old bikes, and you use them, and especially if other people use them, you must expect a few diversions from your ongoing project whilst you fix the other bikes in the fleet. The Square Four has absorbed a bit of time recently and it's now become the daily rider again while the hunt must have takes a little holiday in Norwich.

Therefore, the Model A has taken a bit of a back seat but it's time finally for the next job. This is the tin cover for a kickstart spring.

To start the job off, we can measure the machined register that it fits on the kickstart cover and then we can work out how long it needs to be by measuring the spring.

I'm going to fold the cover up from a strip of 0.9 mm thick steel around a wooden former which I will turn on the lathe from a chunk of sapele, part of an old door.

I've screwed and glued this former to a suitable piece of timber such that I can hold it in the vise

Here's the first try, cut from a bit of sheet with the aviation snips to a suitable width and rough length. With it held in place on the former some tie wraps, I can mark the end and trim.

We'll do a little trial fit on the job:

We need to bear in mind that this cover is supposed to turn with the spring. The spring fits nicely inside it but I suspect it's rather tight on the gearbox end cover.

The only way to find out to tack it together. A couple of tacks show that it fits nicely will turn on the register on the gearbox end cover, so I fully weld it and dress it on the linisher.

The next step is to work out how long it needs to be. I believe that I will need to fold it over such that the inner diameter just fits the kickstart shaft bush.

A little session with the Wiss snips sees it cut to approximately the right length.

Attempting to spin the end over on the lathe was an abject failure - the wooden former just flew out of the chuck so I returned to doing it with a hammer.

That worked reasonably well, and it fits:

There's something fundamentally wrong though:

With a lot of help from the AOMCC, I've learned that LS263 holds LS264 in place and is itself held by the kickstart lever.

Time to try again.

W/NG - maintenance

 Amidst a couple of days of routine maintenance, greasing, oiling, checking stuff, chain adjustment, cables etc. I finished a couple of outstanding jobs on the dynamo.

One was the missing felt pad from the commutator end bearing;

The other was fitting the missing cable boot.

It's starting first time, though there seems to be a lot of piston slap and it's quite rich. 

There's also a lot of oil around. On the drive side it's clear the primary case is leaking; on the timing side we have oil coming from the back of the magneto chain case. I suspect it's not pulled up tightly enough...

SQ4 - batteries

  For the record, let it be known that I have today fitted a second battery to the system on the square for. This returns it to the layout that we ran for the first 7 years or so of its time in service. We now have 19 amp hours of capacity extended from the 12 amp hours we've been running for the last year.

We are back to running these VRLA batteries again: 

A few miles run later in the day showed one-kick starting, there is no fuel leak and the idle is fine. The ammeter showed a charge; the battery monitor also showed a charge and did not go out of the green zone. Since most of the run was quite slow, perhaps I should not be surprised that the battery charger spent a little time returning the batteries to full charge at the end of the day?

SQ4 - a little investigation

 Of course, a broken motorcycle can’t be left for too long, especially when your daily rider has been persuaded from your grasp.

There were a few problems to investigate, possibly associated:

• There was a carburetter leak, or possibly flooding 
• The battery indicator was showing far too much red, considering the 60 miles the bike traveled yesterday 
• The bike refused to start twice yesterday, needing pushing to the top of a hill and roll-starting 

Putting the CTEK on the battery had it charging normally, but it was very flat:

But why so flat? According to the ammeter, the battery does charge and indeed, it was charging on the way home. I did notice the ignition had been left on as Tom had complained the engine wouldn’t idle and it had died when he arrived. I currently believe this has more to do with the battery than anything else.

There is no leakage from the battery with the engine not running and you can measure normal currents with lights on, though with the LEDs fitted to this bike these are minimal. The ignition circuit draws 400 mA without the engine running - I think it would be a good idea to try this with the engine running.

I've also realised that the red spot ammeter doesn't show very much deflection at all - I calibrated the one on the Huntmaster against my bench power supply and there is a lot more movement. I wonder if the Square Four has a 30-0-30 ammeter.

A simple test with a 35 watt bulb revealed that the ammeter appears to be 15-0-15 - while I was doing this test the multimeter was reading 5 amps.

As a first step towards sorting the fuel leak, I removed the drain plug/main jet holder and finding no new fibre washer of the right size, sealed it with a wipe of Threebond 1215. That fixed the leak, and there is no evidence of flooding. 

Amelia started first time like she always does.

As to the idle, I don’t know yet as I haven’t got it warm enough to close the bi-starter.

Model A - Lucas E3 dynamo

So what's next? With the kickstart done and the gearbox back together, my plan is to reassemble the primary drive to get the bits off the bench, and move on to the front forks - a big unknown. They didn't have bushes in 1930, so we are looking at a machining job at home or away. To get there though, I have rebuilt the clutch and next is the primary chain and covers, which just need paint. I'd like to reassemble the dynamo and it's drive, but it's toast. I could either:

1. leave the dynamo in a box for a few months and get on with other things
2. reassemble it mechanically (the body needs replating)
3. Fully restore the dynamo

I've got no nickel plating chemicals, and I have a long list of FH bits that need plating which I don't really want to get into right now (and as of this afternoon, my son has taken the Huntmaster and left me with the Square Four which won't idle...); I don't want to leave the dynamo bits in a box for months, so we will go for option 2. I've also seen at least one picture of an E3 dynamo with a painted body - and I've seen another picture of a 1929 bike which made me realise that you can't really see the body when it's mounted on the bike!

Here's a photographic survey of the dynamo:

In the picture above you can clearly see the damage done to the armature - it's thoroughly bent and unrepairable. Notice that this early E3 has the magneto type open ball bearings and the taper fit for the driving sprocket along with the male thread for the retaining nut. Characteristically, the armature is 157 mm long. Putting all this together enables us to purchase a new armature for this 36 watt dynamo.

I've ordered this repair kit from Rex's Speed Shop which will include the proper bearings:

As I may have mentioned, this is just going to be a photographic survey for future use. Here are some views of the dynamo body and the commutator end casting:

Close up, we can see that the other dynamo and casting has been a victim to the side swipe that this bike has suffered - there is a crack in this end as well. It looks repairable though:

SQ4 - a ride out

 My son made a surprise visit today to borrow one of my CTEK battery chargers. He's not seen the Huntmaster yet and we agreed that I would ride with him halfway home so that he could have a go on it. He was very pleased with it.

However, when he arrived on Square Four he was complaining that it wouldn't idle. I noticed that he'd left the fuel on and the ignition on, and the battery condition light was showing red. I got it started by bumping it down the hill and rode it to North Walsham; it was okay ish but it obviously wasn't happy at low engine revs - but it was charging.

After a bit of a chat at the North Norfolk Motorcycle Museum, I left to go home but it wouldn't start at all - the carburettor was dripping and the battery condition light was still showing red which suggests the battery is not holding a charge. Again I'd left the fuel on, so maybe it was overflowing and the float valve is not working properly, or maybe there's a leak. 

Eventually I got it started by rolling it downhill and and rode it home like a bat out of hell at up to 60 miles an hour. It was charging, and going fine and I got home safely though the front brake is a lot worse than the one on the Huntmaster. 

I put it on the battery charger when I got home and the battery condition light showed red for several minutes, which is unusual - normally if I put it on charge it will go to green straight away. After a couple of minutes it went to solid green which means it's charging or fully charged.

There's something wrong here.