Click images to enlarge
Double click to shrink
Electronic ignition conversion
I am presently in the process of converting my magneto ignition to an electronic battery ignition.
The problem with doing this is that there is no after market "slap on" system available for the /2 except for a unit
that is available at moment from a German supplier, Omega-Oldtimer. I have tried to get detailed information
for this system and eventually gave up. As a matter of fact, their webpage, doesn't show the electronic system
anymore. So, I decided to search the web and make phone calls. I ended up looking seriously at Boyer-
Bransden and Dynatek. Boyer-Bransden appeared to be disinterested so I immediately focused on and ended
up selecting the Dynatek system. Made for the 1970-1978 boxers it retains the original advance
mechanism thus keeping the original /2 advance curve. The Dyva III unit requires a coil. By the way, I have a
12 volt alternator system on my R69S and the retrofit does require 12 volt . My plan is to use the magneto shaft
to position the rotor (reluctor). The picture shows the magneto shaft with magneto rotor/magnets removed.
Machining is required and pictures will follow.....I am waiting for the unit to arrive in post. MORE TO COME
I received my package of EI parts in the post yesterday. I purcased the parts from SUDCO, a CA based
company that deals in new aftermarket motorcycle parts. I did my dealing with Curt who was very helpful and
gave me the proper information to fit the DYNA III on my /2. He had already done a similar retrofit on one of his
Japanese Motorcycles so I figured I could do the same thing with a little machining and patience. The package
contained 3 items:
- DYNA III ignition system, Part# DY 618.707, D35-1 ignition, $131.25
- ProFire coil, Part# NO 618.511, Coil 3.0 Dual , $ 89.80
- Ignition HT lead wires and fittings, Part# DY 618.781, DW-200 Dynawire, $ 21.00
Total cost including shipping via US Air, CA to Beloeil via Canada Post was US$280.00
Today, Saturday December 1, 2001, I went to see my machinist (Laureat Jean) in Chambly to have some of the
parts machined and turned down. The DYNATEK rotor (reluctor) needs to be reamed from 12 mm ID to
15.55 mm . The advance cam needs to get the 2 lobes turned down so that it can be inserted in the machined
reluctor. The reluctor has 2 set screws at 90 degrees and 2 little dimples will be etched on the cam surface to
secure the reluctor on cam proper. The magneto shaft needs to be also turned down at the second step from
15 mm to 14 mm and the pickup plate needs to have it's ID reamed slightly in order to give a good clearance to
the turning mag shaft. The latter I did myself with a reamer taking care not to chew in the electronic circuitry
behind the plate.The plate ID now measures 15,8 mm with the rotor shaft at that point having 14 mm OD, I
have plenty of clearance. Note that part of the reluctor overhangs the magneto shaft where the OD is 14 mm.
There is however good clearance as the ID of reluctor is 15.55 mm. THe reason of overhang is because due to
the dimensions of reluctor (thickness), I need to clear the 2 L shaped metal clips holding back the cam lobe to
the main body of centrifugal advance unit. The parts are supposed to be ready next Tuesday. In the meantime,
I will work on designing a backplate that will be used to fix the EI pickup plate (stator) to the front engine casing.
I will be using the bare aluminium magneto baseplate and the copper points fixing plate with (I hope!) few
modifications. The reluctor (rotor) has one small cylindrical magnet embeded in the anodized aluminium toroid.
The pickup plate has 2 sensor units, one for each cylinder. Both sensors can be individually adjusted to get the
timing spot on....there will be no more seeing double in the timing window with this baby and no more
points to worry about ! Although this unit is a hybrid, I kind of like that I get to keep the designed timing
advance that BMW originally set for my /2. The plate ID now measures 15,8 mm with the rotor shaft at that point
having 14 mm OD,
While waiting for my parts to be machined, I found a place to put the EI module. It is on the sidecar side and
I feel it is unobtrusve to my rig. OK OK, the picture does not appear to give the module unobstrusivity but it looks
really cool in reality! I will however place it so that the wires are hanging at the bottom to prevent any water and
or humidity to enter the module. The unit is said to be impervious to the elements. In this position, the lead wires
are long enough to connect to the pickup plate and the coil. I have a feeling that positioning the coil will be a
problem but I will see once the tank is removed. By the way, I finished reassembling my engine today and
decided to wait untill tomorow to give it a kick with the original mechanical advance and magneto still in place.
Today, Tuesday December 4, 2001, I picked up my machined parts from the shop. For USD150, he
rebored the rotor from 12,0 mm to 15,5 mm. Then he turned down the mag shaft at the second step from 15
mm to 14 mm. Then he turned down the cam lobes so that an even surface was produced and would fit snugly
to the rotor. A groove was also done on the "cam" at 7 mm from end so that the rotor set screws (2) can lock in
the lateral position on the "cam". Finally an adapter ring turned from aluminium stock was produced to hold the
pickup plate to the remaining magneto body parts. Both the aluminium magvneto body base plate and the
copper rectangular front plate are retained in the conversion and were not modified in any way. What is left now
is to fit the assemblyon the camshaft nose, find a place to put the coil and connect the wires which looks
This evening, Monday December 10th, I decided to remove the gas tank and start fitting the EI parts. I managed
to find a place for the dual coil, just in front of the rear tank bracket. I will need to fashion a holding bracket to
keep the coil in place. Due to limited space the front ear on the coil was cut off. I will make the bracket with SS
and it will fasten underneath the horizontal bar that secures the tank at rear . As for the pickup plate, all I
needed to do is add 4 spacers between the copper front plate and the aluminium magneto fixing plate. With
rotor and advance in place, clearance is good in all respects. It is important to bend the advance tabs slightly
inward so that they do not rub against the 4 nuts holding the sensors in place on the pickup plate. Stand-off
distance between rotor and pickup plate is about 1,50 mm. When my coil bracket is ready, I will connect all the
wires and set the timing...pictures to follow later on this week. Replacing the magneto/points ignition with EI sure
removes the clutter beneath the front cover.....especially since I have a /7 alternator under there with all the
extra wiring! I just finished installing the coil on a bracket that is fixed to the bolt holding the horizonal rear tank
This evening (December 12) I put everything in place. The only thing that I needed to figure out is where to get
the feed to the positive side of the coil. By looking at wiring on /2 versus /5, it seemed that connecting to the
15/54 terminal on the board inside the headlight shell would do the trick. I had confirmation from Lonnie in the
slash2 group that this is what he used when he installed a battery/coil ignition as backup on his /2. So tomorow
evening I will do just that. The original wire going from terminal 2 (brown/black) on the circuit board to the coil
was decomissioned (butted at both ends) but left intact inside the wiring harness. Then prior to placing the tank
back on, I will set the timing statically or at least check to see if the rotor magnet sends out a signal to the coil.
Aside from putting tank back on, I need to assemble the HT leads and secure all the extra wiring nice and tidy
undeneath the tank. Everything appears to fit in and hopefully tomorow evening this project will be done and
ready to try on the road over the weekend!
Last night (December 14th) I finished the wiring and assembled everything back together. I just need to put the
gas back in the tank and fire it up. I trimmed the new HT leads with the special integrated coil connectors and
screwed in my Bosch 1.0k ohm s resistor type sparkplug caps. I also added an 10 amp in-line fuse going on
wire from switch terminal 15/54 to coil positive terminal.
So now 3 days later after much exchange with Dynatek, Sudco, Nology Engineering and Slash2 group the EI
is working fine and as expected. What was thought to be a problem with the EI unit turned out to be just a
carburettor problem (too lean). Thanks to Curt from SUDCO for suggesting the final carb adjustment. What is left
now is to try it out for a good run and see how the EI performs. I have yet to break in the engine after having
repalced a seized piston.
I took Friday off (December 21) as the beginning of xmas holidays. Temperature outside was 35F and the streets
were dry so I decided to take the rig out for a ride and check out the EI. I rode for about 7 km to realize that I
had forgotten to turn on the riding lights. When I turned the switch, I was going about 50 mph and everything
seemed ok. I arrived at a traffic light about 1 km up the road and slowed down to idle. When light finally turned
green, I rolled the throttle to find out that my missing problem had come back. Putting the ignition switch back in
the middle position alowed me to resume my course so I headed back to my house a bit dissapointed. The
problem ended up being a bad ground wire between the upper engine mount nut and the diode board which is
part of the alternator 12 volt retrofit I have on my R69S. It took me about a week to find out what was causing
the choking but now I think my EI installation is working just fine and all I need to do now is a little carburettor
fine tuning. Both my idle air screws have been unscrewed to the 2 turn position and all is well. Glad this project
turned out so well in spite of this last technical problem! Hopefully this will entice other /2 riders to thisconversion
There are many benefits that come with this conversion, two of which is simple and speedy timing and
maintenance free (except for advance mechanism of course!).
Instructions (components modified)
Click here for Wiring Diagram
The DYNA III, Part No. D35-1 was designed to fit on 1970 to 1978 BMW boxers. Modifications of the pickup plate, magneto shaft and advance mechanism are required and an adapter ring to fit the pickup plate about the magneto shaft is required. Additionally, a bracket is required to secure the dual coil underneath the petrol tank.
Important :Disconnect battery before proceeding.
1. Fasten the attachment clamp for the DYNA III electric module using the screws and locknuts provided. The clamp and nuts go on the inside of case.
2. Attach the module to the frame in a suitable location.
3. Attach the black wire from the module securely to engine case (ground). Do not attach to frame or carburetors.
4. Remove the fuel tank and remove the front engine case cover.
5. Disconnect the brown and black (BR-SW) wire from the no.2 terminal on the coil/magneto body and butt the end (this wire will no longer be functional following the installation)
6. Remove the 2 x M10 nuts securing the magneto body to the engine case.
7. Unscrew the Allen bolt securing the mechanical advance and magneto rotor to the cam shaft. Remove the advance mechanism from the magneto unit. Separate the magneto rotor from camshaft using proper extraction bolt.
8. Remove complete magneto unit (housing and rotor) complete with points, condenser and coil.
9. Install the modified magneto shaft loosely on camshaft. Place the modified magneto body complete with EI pickup plate in position and secure with washers and nuts previously removed.
10. Fit the modified mechanical advance in position (EI rotor secured) and hand tighten the Allen bolt so that the extension shaft can rotate freely. Rotate the the extension shaft by grabbing the advance mechanism firmly to make sure that the 2 metal advance retaining clips do not rub against the pickup sensor securing nuts. Bend inward as appropriate.
11. Pass the wires from the pickup plate at top of engine case and route by the main harness and out the top. Connect the wires to the corresponding red and white wires of the electronoic module matching the colours.
12. Install a compatible dual coil with suitable holding bracket on frame and connect the brown wire with female spade connector from the module to the negative male spade of coil and the remaining red wire to the positive terminal of coil.
13. Route a new 14 gauge wire from the headlamp circuit board terminal 15/54 out of the shell and back to the dual coil positive terminal on which the red wire from module is already connected. Install an in-line fuse holder along the 14 gauge wire so that the fuse is accessible once the tank has been put back in its position.
14. Tidy all the connections and replace the tank back on frame. Connect fuel lines and reconnect battery.
Timing your /2 Electronic Ignition conversion
NOTE: Refer to BMW owners manual for additional timing information.
Never leave the ignition key in while engine is not running. This could cause overheating of the EI wires over time. The inline 10 amp fuse is there to protect from overheating but is not fail safe!
A) The top sensor triggers the left cylinder while the bottom sensor trggers the right cylinder and each provides +_10 degrees of adjustment. Moving them or the plate clockwise advances the timing and counterclockwise movement retards the timing.
B) The sensor plate must be grounded at the periphery. Make sure not to ground any of the circuitry in back of pickup plate.
C) The sensor to rotor air gap is not critical as long as it is concentric and there is no contact between the parts.
D) Ensure that there are no loose wires about the rotating parts and that they will nut be crushed when replacing the front cover.
E) To time the engine statically, remove both spakplugs and rotate the engine until the S mark on the flywheel appears centered in the timing inspection hole and that the left cylinder (from riders position) is on the compression stroke.
F) Make sure that both sparkplugs are grounded and connected to their respective coil terminals.
G) Reconnect battery and push the ignition key in and start rotating the rotor/mag extention/advance mechanism by hand in the counterclockise direction. Keeping in mind that when the magnet passes the top center and sparks the plugs, that this is the position the assembly should be locked in by tightening the Allan bolt. Before tightening, make sure that the mechanical advance is still locked in the key way of the cam extension nose.
H) To check the position of both sensors, rotate the engine a full 360 degrees to the S mark again (right cylinder on compression stroke) and check that the spark occurs at the moment the S mark appears centered in the inspection hole. If not then adjust the bottom sensor to compensate for the discrepancy.
I) Remove the switch key, install the front cover. Now you can check the timing dynamically with a strobe light and adjust accrdingly.
Important: On startup after having installed the EI for the first time, you may experience poor response at throttle. This is due to the fact that EI requires a richer mixture compared to magneto. You may have to screw the idle air screw in to correct this problem and at worst change the idle jet screw to one step higher (ex. 35 to 40)
Back to Top
When I restored my R69S I had in mind that in the not too distant future, I would have a TR500 sdecar to go
with it. So as I was restoring the R69S I decided early in the process to fit the R69S with proper S/C gearing,
handlebars etc. As the Motorcycle resto was in process, I was looking on and off for a TR500 and more
specifically a BMW "Spezial" which was essentially a Steib TR500 built for BMW. The main difference was that
BMW did away with the Cobra handle, added a blinker on the fender and most interestingly, a S/C hydraulic
brake. I ended up finding a 1950's TR500 which I had shipped from Vancouver to Beloeil. As you can see I had
a lot of work ahead of me. What you see is surface rust. The s/c had been sandblasted 8 years ago and left in
an unheated shed to condensation. The floor pan was completely gone and the S/C had been in an accident
(lots of putty).
Later on, I ended up finding an old BMW "Spezial" frame that had the brake plate. The swingarm was bent
and beyond repair. The axle was a gonner. And the foot step U bracket had been sawn off by PO. I ended up
making a proper chassis using elements from both. The BMW brake plate was not in very good condition and
the ATE hydraulic cylinder had to be reconditioned.Part of the Duralium brake plate had been eaten away
and was pitted pretty bad.Tig welding managed to fix that. The previous owner had rigged an automobile
master cylinder that was actioned with a separate brake pedal along side the motorcycle rear brake pedal. The
design looked pretty cool until I found out that the mechanical advantage was merely 1,2:1; not nearly enough
to stretch the brake shoe spring! So aside from having to restore the sidecar body and frame, I needed to brush
up on hydraulics to redesign the brake system.
Back to Top
"Spezial" Hydraulische seitenwagenbremse
Back to Top