Eletronic Fuel Injection (EFI) For Dnepr (M2B)
Arguably the best available method to control the ignition and fuel delivery on a Dnepr motorcycle is a full EFI kit made by M2B in Belarus (link). As an electronics engineer I was very excited to try this and in 2021 I said 'damn the cost' and bought myself this system to try.
Detailed here are my experiences with the system over time, its strengths, weaknesses and my thoughts on the system.
Arrival and Initial Experience
The M2B system has been designed and is manufactured by a single person as a hobby project which has grown to an immensely impressive small scale production. Artemy has made something that would normally require a full team and all criticism to follow should bear in mind this fact. He is always happy to help and will quickly respond when contacted via VK (@m2boxer_efi).
Initial registration to the M2B website, purchase and payment was very smooth and professional. The website offers excellent information with publicly available guides and schematics (link).
My order was not initially in stock but was manufactured on demand and this process took 2 months. Overall from order to delivery the process took approximately 3 months.
On arrival I was very excited and immediately fit the full system
onto my bike. The kit includes everything except the ignition coil
and its mounting hardware. M2B recommends Bremi 20305 coil (link)
and I would additionally recommend buying a set of suitable ignition
leads such as SKIC-0030107 (link).
Alternative coil from STARK (link),
the mounting holes are slightly different.
One of the Pekar injectors provided in the kit leaked from the body. I replaced both injectors with Bosch 0 280 158 502 (link).
The kit provides O2 sensors and bungs that require to be welded onto the exhaust pipes.
The throttle bodies fit very well onto the Dnepr heads and
standard throttle cables can be used.
There is a slight discomfort as the left inector protrudes enough to
poke into the shin, otherwise there is enough foot and leg space to
use the brakes and gear change.
Photo of the coil and ignition sensor installation. Instructions available from M2B
My initial mistakes :
- Attempting to make my own ignition leads. They did not want
to stay in place, one jumped out during a journey leading to the
bike firing on one cylinder and then to the coil burning out. My
advice is to buy some ready-made ignition leads for this coil and
then cut the ends off to fit through the engine and add spark plug
ends
- Using aluminium for the coil brackets. It fatigue-cracked
very quickly. Solution, use steel brackets.
- Welding O2 sensor bungs off the bike. The fit is slightly
wrong and they are also a different distance from the exhaust ports
giving a slightly different reading between the two cylinders.
After fixing the initial mistakes and fitting the full system on, what happened ?
Absolute failure. Reasons why, detailed below.
List of initial problems :
- The formware of the EFI module was programmed for a different bike. This caused problems both in fueling and ignition.
- Initial ignition angle was setup
incorrectly. It is slightly unclear in the instructions and with
incorrect firmware this was further obfuscated. With Artemy's help I
managed to get it working but it wasn't until much later when I
understood how to correctly configure the ignition angle.
The best way to debug the angle is to fit carburetors on and remove
the fuel injection part from the equation. Only when the ignition is
working correctly can the throttle bodies be fitted. Lesson learnt,
don't get over-excited and fit things without testing.
- Initial fueling and map was incorrect due to firmware. With correct firmware uploaded the bike was still running very rich and global fuel constant required reduction. My bike had compression considreably lower than expected by the firmware and a long process of fuel map tuning was required