Jump to content

M72 timing advance?


Odinn
 Share

Recommended Posts

Hi there fellow bikers! This is my first post here, I'm rebuilding a 1952 M72 and I need your advice on opgrading to a electronic ignition.

I am considering to use the type3 ignition instead of the old points and rotor, but holding on to the 6V system.

Does anyone have experience with that?

Now that the M72 has manual timing advance original, how will she advance the timing efter i have put the new ignition in?

What will be the best coil to use (one that fits under the front cover)?

Btw. I just love the character in those old russian bikes, nothign fits rigth away, everythng has to be filed and custom fit and along the the way she has become the most loveable bike I ever had.)

Link to comment
Share on other sites

I'll be watching this thread, because I'm curious about this upgrade too, but I've not been able to figure out how it would work with manual spark advance.

 

I know what you mean about having to fit and file every part. It would depend at what moment you asked me whether my M72 was my most loveable bike, though. Some days I feel she would better serve as an anchor for a Russian fishing trawler!

Link to comment
Share on other sites

I will buy an electronic ignition system before next spring. Since I will upgrade Nikita from 6 volt to 12 in the future to get better lights I'm looking for a minimalistic system that will fit under the "hood" and that is self-adapting between 6 and 12 volts...

 

I think that you will lose the manual advance when you install EI but I have been thinking about if it would be possible to keep it somehow since I really like to take the idle down to "steam-engine-mode" sometimes. I'm not sure if it will work or if the EI will try to compensate or something, or really what will happen... I'm thinking if it's possible to put the EI on a modified movable base plate so you can delay or advance the sensor... Don't really have any idea what will happen or if I will brake something if I try this...

 

My 2 pence of info about EI brakes down to optical vs magnetic sensors and on the magnetic side (Hall), heavy rotors and strong magnets vs very light "tin-cup" rotors and sensors with weaker magnets... I'm not really sure about how correct this description is since I have a problem with my English at times, especially technical terminology...

 

How big difference is it between SV and OHV ignition curves?....

 

 

I have looked at these systems:

 

Power Arc Ignition (Optical) -----> Click here

 

Power Arc is an optical system that produces multiple sparks and seams to be very customizable. I don't know if it adapts automatically between 6-12 volt and would appreciate if someone could answer that. Some people on the net says that a weakness with optical system are dew, dust and dirt... But how big problem could that really be?...

 

Powerdynamo (Magnetic) -----> Click here

 

This is a system that will not fit inside the original "ignition house". It adapts automatically between 6 and 12 volts but is not so minimalistic. Things has to be mounted on the outside, under the tank and/or under the saddle. It doesn't have multiple sparks as far as I know... Big heavy rotor.

 

Sachse Electronics (Magnetic) ------> Click here

 

Think this could work but I don't know so much about it... It also have a quite big "black box" that would have to fit somewhere together with the coils. rotor looks heavy. No info on dual spark.

 

Omega (Magnetic) ------> Click here

 

------> Click here for instructions with some pictures

 

Another one that I have been looking at and I think could work. Uses the "big rotor" and adapts to 6-12v, alternative with multiple sparks . It doesn't say R71 (M72-K750) anywhere but I think that it could be adapted with a little help from the manufacturer... Depending on how it work with ignition curves SV vs OHV...

 

 

ELEKTRONIC-DATA-KLEIBER (Magnetic) ------> Click here

 

 

------> Picture of installation at Ebay shop

 

 

Does not adapt between 6 and 12 volt, nice installation, no info on multiple sparks. 6v and 12v versions...

 

 

Ural-Hamburgs 6v (Magnetic or Optical???) -----> Click here

 

Looks very minimalistic, not sure if it's optical or magnetic only 6v... Includes twin 6v coil. Doesn't say if it has "black box" for altering ignition curves.

 

 

Oldtimers "Microprocessor" Electronic ignition for M72, K750 (Magnetic) -----> Click here

 

Only 6v uses the light "tin cup" rotor, no multiple sparks, read in other threads here that it works okay...

 

 

 

Rs-Fahrzeugtechnik-Berlins DIGNITION® ignition (Magnetic) -----> Click here

 

-----> Click here for installation picture

 

6-12v automatic, multiple spark, security cut off, minimalistic, nice clean installation (Even if this one is not on an M72/R71), minus is what looks like a big heavy rotor wheel, don't know how big problem that is/will be...

 

I like this because it looks very simple have multiple sparks and adapt between 6v and 12 and that means that I wont have to do anything when I upgrade to a 12v generator... It's just a gut feeling that I have. It's more expensive and I guess I will see quite quick if I wasted my money...

 

What do you guys think?

 

What would happen if the sensor in the last package could be moved by the manual advance cable... Would the sensor try to compensate that because it being fooled to believe it's another speed or what happens???

Link to comment
Share on other sites

Now that the M72 has manual timing advance original, how will she advance the timing efter i have put the new ignition in?

 

I think it works by the RPM:s and is controlled by a program on the circuit board or in the "black boxes" ... Some of the ignitions I have looked on above has adjustment buttons/screws for altering the ignition curve.

Link to comment
Share on other sites

Trying to learn about ignition advance curves.

 

Understand now that it's different for all engine types and also for different engines of the same model...

 

Found a site that explained it to me and even if I sort of understand I can't say that I got any wiser...

 

http://www.starchak.ca/tech/ignition.htm

 

When I use my manual advance I can sort of feel what happens with my engine.

If I put an electronic ignition on it will be a "theoretical" curve for my bike based on the RPM.s... Or am I misunderstanding all of it?...

Link to comment
Share on other sites

You need to find an electronic ignition that is programmed with the advance curve required for your engine.

Manufacturers specify their products accordingly.

 

I am only familiar with those available for Ural 749cc engines, and have installed different types on ours and Friends' Urals.

All very successful and totally reliable for years, so far.

~RN

Link to comment
Share on other sites

You need to find an electronic ignition that is programmed with the advance curve required for your engine.

 

Thanks Russ,

 

What do you think would happen if the sensor could move on a turnable base plate, like the manual advance mechanism?...

Link to comment
Share on other sites

You need to find an electronic ignition that is programmed with the advance curve required for your engine.

 

Thanks Russ,

 

What do you think would happen if the sensor could move on a turnable base plate, like the manual advance mechanism?...

 

You could then adjust the timing properly!

That is exactly how the timing is adjusted for the electronic ignitions systems I have installed.

 

Happy New Year to all! Right safely and often.

~RN

Link to comment
Share on other sites

  • 4 months later...

The PowerArc based ignition can be used on 6 or 12 volt and already comes programmed to operate on Russian based engines.

I just had adapters made that allows it to be installed on engines with the 3 hole triangular mount. We are working with PowerArc to design ignition kits for more Russian motorcycles. (and other motorcycles, cars, and tractors)

As this is being written we are working on a M72 project so I will post pictures soon.

 

www.c5ignitions.com is our website

Link to comment
Share on other sites

  • 3 weeks later...

The Type III, IV, and Type V all have an electronic ignition curve that kicks in starting at around 1000 rpm. The start of the curve is the 5 degree static advance (more or less, there's several degrees of flexibility here). So, rather than arranging the mounting plate to be "fixed", you'll need to modify the plate, allowing it to rotate. The pate's mount holes are already elongated, but perhaps not enough to make you happy. A control cable from the handle bar, through the front cover, and hooked to the plate will work if the cable is stiff, and your plate mounting modification allows freedom or rotation.

 

Assuming you can use the cable to attain a plate rotation of minus 10 degrees retardation, the auto spark advance will still start kicking in at 1000 rpm. If you are in 1st gear and stay under 1000 rpm, you will be able to "crawl", but not for too long, the engine will overheat.

Link to comment
Share on other sites

We have sent an ignition to Sweden for installation on an M72. I will let you know when our customer has installed.

I have been toying with timing curves for our C5 (PowerArc) ignition on my Solo bike with some interesting findings.

Timing has been lowered slightly in the 2,000 to 3,000 rpm to prevent a bit of detonation my bike had when staying in top gear.

I'll share the timing curve once my testing has been completed.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...