THIS SITE WAS TAKEN FROM BEN´s
TIM 1 Transistor ignition module
Why? No reason really the points condenser set up
in these singles are perfectly adequate. Especially with the single cylinder
engine there is no lack of time (dwell) keeping the points closed for
full coil saturation. So why? Mostly to satisfy a curiosity and rekindle
a very basic interest I had with electronics years ago.
I'm no electronics guru, it wouldn't be hard to know
more about electronics than I do. So your more than welcome to contact
me and make comments or suggest any mods that could be made.
The module does however have a few advantages.
* There is no need for the condenser.
* Since the points are only switching milliamps there
is no danger of the points becoming pitted and burnt. Theoretically they
should last almost forever.
* The switching is done almost instantaneously through
the transistor, inducing a high current to flow through the secondary
windings giving a hotter and "fatter" spark at the plug.
* Easier starting and cleaner fuel burn.
* And it can be easily reverted back to the standard
Tim1 still uses the existing points setup to do the
initial switching in the primary circuit, however TIM2 will incorporate
a hall sensor to do the on off switching making the setup almost fully
After bench testing the circuit I built my first module.
Since the condenser is no longer needed it provides for the perfect place
to secure the TIM1.
Transistor ignition module testing and the finished
unit mounted on the points plate
I sent my first TIM1 to a friend in France whom also
has an R25/3 and asked him to test it for me. My greatest concern being
heat. Electronics don't like excessive heat and under the front cover
of the generator things can get pretty toasty!
Oliviers first report,
I've starded to test your system last week-end on
my byke lately on sunday evening! So the trials were in my parent's garage,
it was so rainy outside that I wasn't able to drive outside. I've wired
the electronic ignition instead of the condenser without fixing it on
the contacts block, because of a matter of time...
Before that, i've started the engine with the original
ignition to be sure that nothing else could matter in the change. Everything
was working perfectly, so I've wired your device.... One shot on the kick
to start the engine and....It works!!! So I decided to let it work some
seconds at a low speed. Then I accelerated the engine and 15 seconds later
everything stopped... :-(
I thought at first the electronics could have burn
but nothing was hot. So I've checked the cables and I've wired it again..
The problem was with the ground- I choose a point with bad conduction-.
So I started again the engine and it was OK :-). The other problem I had
then was that my engine was too hot and started to be difficult to start.
I hope I will have time this week end to fix it completely and try it
on the road. I'll take also pictures of it for you. The difference with
your ignition is that my coil is not the original one, it's placed under
the tank and not near the contacts under the cover box. A small one is
very expensive and I've heard that it's sensitive with heat in the front
box on the engine.
Oliviers second report
"I had some rides around my parents house, and
it was really good! the engine seems to devellop more power, and NOW the
starts are really easy ( easyer than before, because it was starting really
well before but today it's more powerfull)"
"I had a ride with my bike yesterday, it works
well, and I say again : the engine seems to developp more power ...
"I'm very glad that in the end the ignition was
working good, and it's interesting to see that the engine developed more
power, and you asked maybe you are imagining it :-)))".
This feeling comes from the acceleration which is
better, torque also at low motor rpm; perhaps the maximum power is not
increased, I should test it with the maxi speed to be sure...that I 'm
not imagining it ;-)."
Pictures of the TIM installed on Oliviers bike
You too can build a TIM1
The five components needed
Although I'm suggesting that it be for the r25/3 it
should fit all models from the R24 through to the R26. These models all
used basically the same generator housing and points plate. The differences
in power generation between models are of no concern since the ignition
consumes so little energy.
This circuit uses the original points to switch the
transistor, which in turn switches the low voltage windings of the ignition
I'm using a 10Ohm resistor (R2) between the points
and base of the transistor to keep the amperage in check though still
provide enough so the transistor is saturated and will switch full amperage
through the coil. By actual measurement the points are only passing approximately
The PNP transistor (Q1) used is a TIP2925 power transistor,
which is capable of switching up to 15 Amps more than enough for the ignition
system. In reality just about any PNP transistor can be used as long as
it has the required power rating.
(D1) is a backwave diode to protect the transistor
from the high negative voltage generated by the collapsing magnetic field
in the coil. (D2) is a LED, which is used for timing purposes. When the
points are open the LED is on, when the points are closed the LED is off.
It's also there to indicate that there is some life in the system. (R1)
is a 470Ohm resistor to keep the LED amperage in check.
At this point I must emphasize that at no time should
the ignition be left on with the points in the closed position for long
periods of time. The transistor will be passing full current continuously
and it may get "fried", not to mention that the coil will overheat.
Building the TIM1
There are many ways of making the Printed Circuit
Board (PCB) though I used a very rough and ready method. If you really
want a professional looking board then go here http://www.electricstuff.co.uk/pcbs.html
This site has lots of good information for making PCBs. My method uses
the minimum of equipment.
You will need
1 Single sided copper clad PCB
2 Permanent marker or etch pen for drawing onto the
board. Through the suggestion off another site I found that the Staedtler
Lumocolor 318 Red permanent was the best.
3 Ferric Chloride for etching the copper
4 A selection of very fine drills 0.4-1.2 mm
5 Acetone for removing the permanent marker after
etching and drilling
6 Scotch brite pad for cleaning the PCB before soldering
the components to it.
7 Soldering iron with a fine tip and solder
The first thing is to cut the PCB into shape; small
2.5 X 5.0cm rectangles are the correct dimension. You will need a very
fine toothed hacksaw or jigsaw. Cut 3 or 4 pieces as you may make mistakes
while etching, drilling soldering etc.
Plan on the PCB where you want to place the components.
For this I used a piece of cardboard and stuck the component pins through
the card, you can then mark onto the PCB where each of the components
will be placed. The component pads can be drawn with a stencil and the
tracks in between can be drawn free hand. Once the pads are drawn it's
basically a matter of joining the dots with the marker. Make sure that
the pads are large enough to get a good connection between the solder
and components. Especially with the transistor as the pins are rather
large. The other components have much finer pins so the pads can be smaller
The tracks from the transistor to the base and coil
output should be at least 3.5mm in width, enough to carry the current.
Between the other components such as the LED the tracks can be much thinner
as the current is much less.
Allow the freshly marked PCB to stand for a while
allowing the solvents from the marker ink to evaporate fully.
Getting a good clean etch is the most difficult part.
What we are doing is dissolving or etching away the copper that is not
protected by the marker ink. Only a very small bath is required, I used
a simple water glass. Ferric Chloride is extremely corrosive so you don't
want to splash the stuff around, especially onto your hands and into your
eyes. Use protective gloves and eyewear.
250gr of the Ferric Chloride pellets will make up
500ml of solutuion.
The etch process is also improved if the bath is kept
at a constant luke warm temperature, approximately 40C. You can do as
I did. Start with warm water when first dissolving the Ferric chloride
crystals and then place the glass into a bowl of water on the electric
stove (better to do this when wifey is not around)
The bath can be used several times so it's a good
idea to mark and etch a few boards just to get the messy part of the project
out of the way.
The etching requires constant agitation and it's best
to have the copper side of the PCB facing down to allow the free copper
to sink to the bottom. You can either stir the bath continuously by hand
or do what I did and sacrifice the fish tank air pump and constantly have
a jet of air blowing into the bath to keep the solution moving. This also
gives a much faster etch with cleaner track lines. The PCB can be removed
periodically from the bath to observe the progression of the etch. It
is quite obvious when the etching is complete.
Remove the PCB from the bath and rinse it under cold
running water. At this point we have the component pads and tracks remaining
on the board. I like to leave the marker ink covering the tracks until
after the drilling.
It's really handy if you have a dremell and a small
enough chuck to hold the drill bits. There are purpose built drilling
machines and stands for drilling PCBs, however if your very careful you
can drill the component holes by keeping a steady hand. Try to keep the
drill bit as perpendicular to the board as possible, and drill through
the board into a soft piece of wood. It also helps if you can mark the
center of each pad to be drilled with a very fine center punch and a light
tap with a very small hammer.
After the drilling is complete you can then use the
acetone to remove the marker ink from the PCB and then rinse again under
cold running water. Your left with the shiny copper pads and tracks ready
for the components to be soldered to.
Before placing and soldering the components it's a
good idea to give the copper tracks a light rub with the scotch brite
pad, especially if you have left the board standing for a few days. This
helps to remove any oxidation that may have developed which prevents a
good solder joint.
The components can now be placed on the PCB. The pins
pushed through the drilled holes. Do not trim the pins until you have
soldered each component. Also do not forget to solder the connection wires,
there are three wires. One goes to ground, the second going to the negative
side of the coil and the third to the points.
I'm no expert on electronics soldering, suffice to
say that you try not to overheat the components. These components are
not particularly delicate so even the greenest novice should be able to
complete the soldering.
I finished the TIM1 of by spraying an electronics
lack on the back of the board. These lacks are silicone based and heat
resistant, which will guard against shorts and protect the copper circuit
Thanks to Olivier in France for testing the TIM for
me, and to Bart in the Nertherlands.