Electrics – charging system

The Ducati 250 has does not have the correct regulator/rectifier fitted. The original probably gave up at some time over the last 50 years of its life and a previous owner fitted what looks like a British bike system that might even be older than the bike itself! The two parts are separate and are shown in the next picture by two green arrows.

oneThe other thing that can be seen from the picture above is the amateur wiring using any old bits of car and household cable with Lucar connectors crimped onto them. That will all need to be changed to look more original. While this old system was fitted I checked the voltages, Battery was 12.83 volts without engine running, I have a feeling that my voltmeter is over reading by about 0.3 volts. With the engine running it went up to 15.4 volts, so it is charging the battery, but even if that is 15.1 after deducting the assumed voltmeter error, it is too high for my liking. with the puny 35 watt headlight on it dropped to 13.7 volts, indicating that the 40 watt alternator is getting near its limit.


I bought this regulator/rectifier from ebay for the grand sum of £17 from China. It claims to be a Mosfet RR, but I am not so sure for that sort of money. Mosfet is a new type of RR that is bang up to date, it generates less heat and is supposed to be more efficient. Read about it on Google if you are are an electronics buff. The fact that it has three alternator inputs (I have marked them in yellow) say that it can be used on a more modern 3 phase generator, but in this single phase application it is fine to use just two inputs as that is all that comes from the generator. The other two connectors are for battery positive and earth.

threeThis is the new one fitted. There is plenty of space under the seat so it will get plenty of cool air.

The voltages are a bit different, the battery was still around 12.8 volts, but the running was now at a much more controlled 14.4 to 14.5 volts. Switching the light on still dragged that down to 13.7, so the battery is still charging.

On an old bike with no electronics the original 15+ volts would probably do little harm. It might shorten the life of the battery a bit, but you may never notice. I intend to fit an electronic ignition system made by Elektronik Sachse in Germany, but having spoken to the company it seems that there have been a couple of failures of their electronic boxes (I understand that the rate is miniscule, about 2 to 3%), and that may be due to the users bikes charging system producing an over voltage. There website is CLICK HERE.

This regulator will also fit my wife’s Ducati ST2, a bike that is known for weak electrics and a bike that is also fitted as standard with a single phase generator.

Steering head bearings – 250

A design from the 1950s or before. The Ducati singles, with one exception, use non-caged ball bearings, 24 in the top and 24 in the bottom. As ball bearings wear there is no way that any adjustment can be made to take up this wear, taper roller bearings would be much better. The fact that they are non-caged does not help either as each bearing needs to be individually inserted into the bottom race and then the top race, as soon as one 4.7mm (3/16″) ball escapes the whole lot has to be dismantled again. Many people have found that as they dismantle the top yoke all 24 balls fall out of the bottom bearing and roll around the garage floor. This did not happen to me as I had prepared.

I ordered 100 stainless steel balls from ebay for around £4.50 and am waiting for delivery. The play is quite extensive in the steering at the moment so I thought that it might be a good idea to clean and grease the existing bearings. After removing all of the balls and removing all signs of grease from them I counted – 47 bearings! One had gone, but nothing was on the carpet in my work area and I had heard nothing fall, so assumed that there had only been 47 in there in the first place. This is an area that needs constant maintenance so I assume that in the 50 years if Dinky’s life, they have been looked at before. Some pictures:


Looking down into the steering head with both the top and bottom inner bearing cups fitted.


This shows the stem fitted and the large (standard) gap around the tube.

When the top ball bearings are fitted into this cup with grease to stick them into place then the top cup can be fitted to hold the balls in place. The top yoke would then be fitted with the nut to tighten everything up. It seems that a previous owner had not been a fussy as I am and one ball had escaped without his noticing. The ball had ended up between the bearing cups and the stem resulting in some damage to that stem, as can be seen in the following pictures:



I can only assume that the result would have been very rough steering and that he eventually dismantled it and removed the damaged ball and reassembled the whole lot with 47 balls.

I shall probably drop some weld into this area and refinish it, but it cannot be seen and does not really make the stem weaker, so might leave it.

I think that a taper roller bearing kit might be on the cards for next winter!

Speedometer on old bikes.

And some new ones too!

To tell the rider what speed the bike is doing involves a speedometer being driven off something that is directly connected to the road. The only things that touch the road while you are riding is the tyres and that is the problem. New tyres are a bigger circumference than old tyres and different makes can also be different. Then there are sprockets that drive the wheels, they may have been changed to give different gearing, this would not matter if the speedo drive was off the front wheel and that wheel still had a standard sized tyre fitted. For all of these reasons all bike speedos are designed to over read by up to 10%. If the speedo had been accurate with worn tyres at 100 kmh and then new tyres were fitted, the speedo would be showing 100 kmh while the bike was actually travelling at 110 kmh, speeding fines here we come.

The problem with the small speedo fitted to a 50 year old Ducati 250 that i happen to own, is that the vibration will swing the needle back and forth so that when travelling at 60 Mph (yes it is in mph), it indicates somewhere between 35 and 65, and I would need to ride with reading glasses on to see that. The other problem is that all of the cables from the handle bar controls want to pass the speedo face, and you can bet that with a bit of vibration they will find their natural place – across the middle of the dial!


The most accurate speedo that you could use is a GPS driven one, which will show you a very accurate speed at all times, whatever tyres or sprockets were fitted to the bike. Many of us have a GPS speedo in the form of a smart phone or tablet. I have a small Android phone that I use with an app called “GPS Speedo”. The app is free to download and looks like this:


Okay this picture is taken while doing 63 kmh in the car, but a strip of stick on Velcro on the back of the phone will let me attach it to a bike too. It is far more visible than the bike speedo, and even tells me an average speed in the bottom left corner of the screen.

It would be great is someone in China would make a small screen like this with a GPS receiver and an Android operating system, but no phone, SIM card, memory card or camera bits inside, to use as a GPS speedometer. It would not need to be expensive, after all the phone in the picture above was only a €59 item. Perhaps someone does.


No, a classic bike will never be finished. Dinky the Ducati is ready for the road but there are still some minor things to be done. I took her out for a quick 5 mile ride today and can confirm that she runs very nicely.

Things that are left to do: When I returned from the road test, I got my wife to sit on the bike while I checked the front to rear wheel alignment. A 2 meter long aluminium straight edge showed that the chain adjusters were out at the back meaning that the the back wheel was going in a different direction to the front. The steering head bearings are loose and there is play in them. This is a common fault on the Ducati singles and involves 48 3/16″ steel ball bearings. I have read that these have a tendency to escape around the room if disturbed. I priced just the balls up in the UK at a Ducati specialist and they came to £7.50 plus postage for 48. Knowing that I could end up paying double  with the P&P I looked on ebay, 100 ball bearings for £4.48 and free postage.

I will also have to look at the rear shocks, I believe that these can be rebuilt but parts will be needed, so I will have to make an order of those before I start.

I am in the process of making all of the tools that I need to set and adjust the ignition timing. Ducati never put any timing marks on the 250 narrow case bikes so pointers and timing discs are needed and then a piston stop to determine TDC. I have been looking into electronic ignition systems and quite like the one offered HERE.  The company is based in Germany, and surprisingly just a short distance from where I lived as a child for many years and where I was based in the Royal Air Force for a while. I cannot seem to get hold of anyone on the phone at the moment so will try again in the new year.

If I do buy the system then I will write a review and make a video of the installation.

Finally, here are a couple of pictures of the bike as she is now with a picture of the bike on the trailer when we collected her last month.

p1080041s p1080037s

As she was:


Ignition key

The standard ignition key for a 1967 Ducati 250 single is so basic that any bent nail would work to switch the ignition on. If someone wants to steal a bike then they will probably lift the bike into a van, but I am not going to make life easy for them. As I never had the key for Dinky, I used a fuse holder inside the headlight and just inserted a 10 amp fuse to switch the ignition on.

I bought an ignition switch from ebay for the grand sum of £3.50 but at least it has a double sides key and can’t be switched on with a bent nail. The only thing was fitting it. I do not want the do anything to Dinky that is not reversible, that means that she can be returned to a standard bike without any effort in the future. For that reason I cannot just remove the old ignition switch from the headlight shell, enlarge the hole and fit the new switch, as that would damage the shell. The end result was to make an aluminium bracket that fits to the top of one of the front forks. The new switch, with key, is indicated in green in the following photos , the red arrow is the old switch.

ign2 ignsw

The result looks quite neat.

The next job was to fit the headlight for the first time. An LED bulb was fitted into the sidelight position to be sympathetic to the puny charging system on this old bike and will be used as a running light. If I switch the 45 watt headlight on instead of the LED then it will use just about all of the electrical power used by the little bikes generator.  I was surprised to find that the headlight lens is plastic and was just thinking how advanced Ducati were in 1967 to fit plastic lenses, my guru Craig, shattered that illusion and told me that it should be glass.


It does look rather cute now though.

As most of the major stuff is done for now on Dinky the Ducati, I shall move back to some work on Ronnie the BMW RS with his cafe racer conversion.

Interesting find

When fitting the front tyre I noticed that the rims have been changed to alloy ones at some time in the bikes life. Care is needed when removing or fitting tyres to alloy rims as a normal tyre lever will damage the rim very easily.

I took the time to clean the wheels up before fitting the tyre, and Scotchbrite with WD40, in the bead area, followed by a cloth and T cut, on the whole wheel, works wonders. The front was done and the tyre was fitted without incident.

When it was time to do the rear wheel I found that the tyre was very tight on the wheel. As I did not want to use tyre levers at all I cut the tyre from bead to bead across the tread and removed it. Then came to cleaning the rim, it was different to the front wheel and just a bit of T cut had it shining like chrome. The alloy is a much better quality than the front rim. Here is a picture of the shine after a few minutes cleaning:


Then I cleaned the writing on the wheel and this is what it said:


The name BORRANI is well know in vintage bike circles, they used to produce very expensive alloy rimes for all sorts of bikes.

I made sure that I used plenty of soap that I stole from the bathroom to fit the tyre and the wheel was kept in perfect condition.



We went out to lunch today, a 5 course meal with wine and coffee included at €14 a head, and all home cooking. All the bikers who have visited know exactly which restaurant we ate at!

When I got home there was a missed call on the home phone, it was Dafy Moto in Perigueux. I knew exactly why they were phoning, my new tyres had arrived for the 250. I immediately got back into the car and shot into town to collect them, with 2 new tubes and a bottle of 20 weight fork oil.


The tyres have a very sporty tread pattern for such old sizes, but I suppose that there must still be a demand for them for some older bikes. The prices can be seen on the labels, but so can the max speed, 150 kmh or less, and this might be a problem as some of the 250 Ducati’s were capable of 170 kmh. I guess I won’t be asking that much of her, if I need some speed then I’ll take the 848 out.

The front tyre is now fitted to the very nice alloy front rim. Fitting the tyre took nowhere near as long as cleaning the rim up. Sometime in the past someone has used steel tyre levers and marked the rim, but that is all now polished out.

Tomorrow will be the back tyre and then a fork oil change. I will keep the old tyres for a laugh as they have been fitted to the bike for at least 24 years and still hold air!