Updating the Lucas MCR1 Voltage Regulator

The little Lucas MCR1 is used with the short Lucas E3 dynamos, like the one fitted to my W/NG.

I like my bikes to look period, but I don't mind updating them to improve performance if there's no visible sign of it externally. The MCR1 was not working, and since I have a similar electronic regulator on my SQ4, which has been looking after my charging system for years, I have no qualms about updating this one.

The update to the SQ4's MCR2 Regulator is shown in a previous post. Today we are looking at the MCR1.

I am going to fit a modern V-Reg 2b dynamo regulator which is designed to replace the mechanical regulator with modern, reliable semiconductors, can handle up to 100W at 6V and even more for the 12V version provided the dynamo is capable of delivering this power. This device is proven and reliable and is available in Positive or Negative earth. 

New features of the 2b include: 

• Current limit to the field winding, allows excellent performance when using a 6V dynamo on a 12V system while not straining the dynamo. 
• Tougher electronics, with the introduction of higher energy spark suppression to reduce spikes generated by the dynamo. Improved "thermal foldback" which progressively reduces output power if the regulator gets too hot, indirectly limiting the dynamo from excessive current. 
• Better servo loop stability, with new electronics which 'predict' when the output voltage is nearly correct and control the field current earlier.

Mine came from AOServices, who manufacture the V-Reg. You can buy them from a number of other suppliers, but Alan Osborn at AO provides a fine customer support service here in Norfolk. When you order your regulator, you must specify the polarity - a positive earth regulator uses different components to a negative earth regulator, and you cannot convert them. However, the same V-Reg 2b will run a 6V system or by cutting a simple wire link will run a 12V system.

Here it is, with the original 1942 MCR1 quaking in the background. That little green wire is the 6V/12V link.

To get inside, undo the wire clip and remove the cover to reveal the coils & terminals. We'll be removing those coils in a moment:

Here's the underside, showing the two screws holding the bobbins in place:

The cover is stamped with the month and year of manufacture:

Now to start work. The original D terminal screw is soldered in place - peel the solder away and remove both of the visible screws:

The coils will now be loose. Cut all the wires to each of the terminals, being careful not to damage the terminals:

Lift the coils away:

Remove the clip. It's going to get in the way:

Clean up thoroughly. This is a glass brush - it's quite abrasive and does a fine job of cleaning the terminals and the muck around them. Clean the rest down with a spirit wipe.

Take a small soldering iron (this one is a variable 60W iron) and remove the solder and any remaining strands of original wire from the terminals. You can use a solder sucker if you need to.

Then clean the terminals with your glass brush or a sharp knife. Make sure the holes are clear.

Cut off the eye underneath the regulator. It's connected to the D terminal - you don't want charging voltage escaping into the rain. It easier to do this from above, unlike my picture:

Now, the MCR1 is a lot smaller than the MCR2 we upgraded for the SQ4, and the mounting for the V-Reg 2 needs to change. Here I'm using four adhesive pads to stick the V-Reg to the Tufnol insulated base of the MCR1. Don't stick them down yet.

So here we have bared the wires and carefully threaded them through the holes in the correct terminals. BE CAREFUL! you don't want to get this wrong and destroy your new regulator. Bend the bare ends to align with the terminal and increase the strength of the joint.

Now solder the wires in place. Make sure you have heated the terminal effectively, so the solder flows cleanly and wicks into the conductor strands. Don't melt the solder directly with the iron, but let the work heat the solder - that way, you know the wire or terminal is hot enough to make a good joint. I'm using electricians cored solder here:

Coil the wires above the regulator such that they stay within the MCR1 cover, and retain with a small tie-wrap. We don't want to introduce a fatigue failure or have these wires trapped somewhere.

All done:

Finished, with no visible changes:

And the bike is charging:

Misfires & Winter Jobs

I've tracked down an annoying misfire that may be of help to others. After a while, my Square starts to idle very roughly; so much so that I have had the carb apart for cleaning several times. The misfire seems to occur when I am on the way home, and I thought that it was happening when the engine was hot.

I've started to realise that it is down to the No. 3 plug terminal. When the engine has been running for 50 miles or so, there is enough vibration to back off the nut on the plug, with the result that the plug terminal sometimes shorts against the inlet stub...

Better HT cable routing required. I also noticed that my HT cable routing fouls the Bi-Starter mechanism...

It's time to think about winter jobs on the bikes, especially as the W/NG is nearly done and I will have at least two to choose from. For the SQ4 these are:

1. Fix the speedo and get the blurred dial replaced
2. Get a new slow-running screw for the Solex
3. Decide on removing the indicators or not - I need to do something, because the indicators are regular tungsten bulbs and the load causes the LED headlamp to flash with the indicators. This is a bit disconcerting at night...
4. Replace the front wheel bearings with sealed bearings
5. Replace the front inner tube which leaks slowly
6. Look at the brakes again as they bed in
7. Make a new tool roll
8. Fit a couple of transfers
9. Change the oil tank for the one with a good filler neck thread

And for the W/NG:

1. Grease the forks & replace the missing nipple
2. Maybe replace the fork bushes
3. Tighten the brake torque arm anchor or weld it in
4. Make a T-bolt for the exhaust clamp
5. Adjust and lubricate the primary chain
6. Have a look at the clutch
7. Change the regulator to a V-Reg
8. Fit a couple of transfers

All good fun! And if I get a bit of bench space, and any spare time after that lot, I might start looking at the various welding jobs on the Huntmaster tinware...

Old Warrior Back in Action

So, over a year since the Old Warrior arrived on our shores, I've been out for the first proper ride and what a cracking bike it is. The gearing is very low as expected, but everything is working (except the voltage regulator which I knew about), the engine starts easily and pulls very well and the handling is rock steady.

I've never ridden a rigid bike before, but it feels more secure than my Anstey-frame SQ4 and my plunger Bantam. I've not hit any bumps yet, cranked over, so perhaps I've not really experienced the darker side of rigid bike handling but right now it feels good. I've not seen much movement from the forks - perhaps they are very stiff. They certainly need a session with the grease gun. I have the tyres set at 24 psi at both ends, which feels fine at the moment.

The brakes seem OK - better than the SQ4, but then this is a much lighter bike. Good feel and quite powerful, though there is a clonk from the torque arm. Clearly that's loose & needs sorting out.

The engine sounds a little rattly and is burning oil off the head - there has been some leaking from the rocker feed studs, which I have nipped up, and there is oil in amongst the rocker boxes. This is merrily burning off but I am not sure if it is still leaking. Time will tell. The primary drive sounds like the chain is too tight, and the clutch may be dragging a little, but the oil is returning happily.

So here is the job list:

1. Grease forks & replace the missing nipple
2. tighten brake anchor
3. primary drive thrashing
4. clutch dragging

We'll see where the next trip takes us!

Oil burning off the cylinder head

Same bike, same place, a few years earlier?

MZ Frame coming along

The TS125, in another part of Norfolk, is coming along slowly. This week, some reassembly and some painting.

Front mudguard:

Headlamp brackets and fork shrouds:

Here's the centre stand spring being stretch in time-honoured fashion

Back on the frame:

Spanners removed and the stand is back in action:

Fork yokes back in:

SQ4 - Oil Line Mod

I'm having a few issues with oiling at the minute, some of which are due to my own stupidity and some of which are not.

I have had persistent problems with the feed union to the cylinder head, which despite re-tightening on several occasions has always backed off after a few hundred miles. Seeking advice on this on the AOMCC forum, Nev Hunter from Australia pointed out that it was the fibre washer I was using that was at fault. This area gets so hot that it will cook a fibre washer...

In this location you must fit a copper washer:

The second problem was not of my making. There are two oil lines leading up to the cylinder head from the crankcase; from the front main bearing as shown in this diagram of the 4G, and from the rear main bearing, a banjo under the timing cover on later bikes. The assembly consists of two lines _ a 3/16" line for the gauge, and a 1/8" line for the rockers which seems illogical but the 1/8" line is there to choke the feed to the rockers and to maintain back pressure at the main bearing.

Pressure loss in a pipe is affected not only by the size of the hole but also by the length of the pipe, so that long, small pipe to the rocker creates a restriction in oil flow to the rockers which has the effect of increasing oil pressure at the banjo, and hence increases the pressure the gauge sees. Mathematically, the effect is demonstrated to engineers by the Darcy-Wiesbach equation which has been useful in most of my oilfield career when predicting the performance of hydraulic fluids and chemicals racing along thousands of meters of small bore lines and back.
Problem was, several assemblies are out there that are the wrong way round, which results in over-oiling to the rocker box and a gauge that under-reads (since the oil pressure to the rockers is lower), so we will set about fixing the problem.

4G Lubrication System

You need to take the tank off to have a look.

Here are the oil lines - the 1/8" pressure gauge line and the 3/16" rocker feed line. We are going to swap these around:

Here I've cut the old 3/16" rocker feed line and fitted a 1/8" equal union, which will mate directly with the existing line to the gauge:

Using the remains of the existing 3/16" rocker oil feed, just the last few inches to the head, I've fitted a 1/8" nipple & nut to mate with the old gauge line coming from the double banjo under the timing case. In this picture, I'd kicked the engine over to prove I had oil coming out of those lines:

I took this picture after the first road test, when I discovered that the rocker box soldered joint had failed - poor penetration caused by bad fluxing or low heat:

From the beginning of the rebuild, my Four has exhibited the same behaviour with respect to the oil pressure, namely that it will show about 55 psi cold, idling or on the road - governed by the relief valve. This drops to about 25 psi at 40 mph when really hot, and about 10 psi at idle - all this on Penrite 40/70.

Now that I have the rocker box/pressure gauge oil lines the right way round, its completely changed. Same oil, but now I see 60-65 psi cold, and about 50 hot; this drops to 25 psi at a hot idle.

I'm a happy chap. I might go back to a lighter oil, just so I can kick it over in the winter without a hernia.

Grease Everywhere

Some while back, on a very hot Norfolk Summer day, the SQ4 decided that the rear hub had had quite enough of that nasty, sticky grease thank you and vomited it all over the rear tyre and brake.

The trip home was rather gentle, especially as I had to descend from Norfolk's highest spot (!) to sea level, about 90 metres.

Pulling it all apart, there was grease everywhere. The parts washer is a very useful tool:

There are quite a few parts in the QD rear wheel, which is why I am writing this post. Here's an illustration from Draganfly, where we buy all the parts we need:

Putting wheel back together goes like this:

Put in the 4440B-50 grease retainer

Next comes the bearing. I'm using a modern double seal bearing, so we don't have a repeat of this grease leakage problem:

Knock the bearing in

Add the spacer 4346-50

Use a good quality peg spanner designed for the job, and the locking ring will go in easily. I've omitted the original seals, since I am using double sealed bearings.

Eagle eyed readers will notice the 4346-50 spacer is missing...

Locking ring trial fit

Turning the wheel round, we put in the 4471-50 Bearing Spacer Tube, whose smaller end locates in the 4440B-50 Grease Retainer. The Spacer Tube serves to allow the wheel spindle to pass through both sides of the wheel easily. The larger end of the spacer tube locates in another Locking Ring on the other side:

That's the wheel finished. Next, we turn our attention to the brake drum. Clean the bearing recess thoroughly, and include the slot for the circlip. I use Wagamamma chopsticks for jobs like this. Being bamboo, they are strong, flexible and be carved to the shape of the slot. When its all clean, press in the new bearing.

The pictures show the bearing in place, along with the 4440-50 Grease Retainer and the circlip.

Don't be fooled by this picture though, the fixed spindle comes next, with it's circlip.

With the grease retainer in place, you can fit the fixed spindle but you can't get the circlip in...