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Collection of info on electrical upgrades to the /2 BMW motorcycle.

Collected emails by Allan Atherton and posted here as a convenience, thanks Allan. 

Comparison of 12-Volt Conversion Systems

Wolter Klaus , 14 Mar 2002

Comparing: http://members.aol.com/antiquebmw2/conversion.html   and http://www.dynamo.mz-b.de/bmw/bmwmain.htm

-Vech's system replaces the 6v generator with a 12v alternator.  The MZ-b system replaces the 6v generator with a 12v alternator AND it replaces the entire ignition system. 

-Vech's 12v conversion system is 200 watts while the MZ-b is only 150 watts. 

-Vech's system uses a true alternator, where current through the field controls the output of the alternator.  The MZ-B system uses permanent magnets for the field so they have to regulate the higher current from the stator windings.  Basically, the regulator is controlling less than 4 amps in Vech's system while the regulator in the MZ-b system is controlling up to 11 amps of current.  (150W / 14v = ~11A)

-Vech's system does not effect the (Bosch magneto) ignition system that came standard on the /2.  The MZ-b system replaces the ignition system.  With the MZ-b system you remove the entire magneto system: Coil, points, points-plate, rotating magnet, pole-piece, condenser and mechanical advance.  The MZ-b system uses a dedicated winding, located in the alternator, for their ignition system.  They replace the mechanical advance with an electronic advance and the coil is similar to the coils you find on newer cars that use a wasted spark ignition systems.  The MZ-b system will run fine without a battery in the bike.  (They suggest you put a small capacitor in its place if you do not install a battery.) It's a modern magneto ignition system that uses electronics to replace the breaker points and the mechanical advance. 

-Vech's system is all contained neatly inside the engine covers.  The MZ-b system hangs stuff outside in the breeze to avoid the biggest enemy to electronics: Heat. 

-I'm not sure how well the connectors, used to plug the various modules together, in the MZ-b system would survive out in the elements.  They don't look to be as moisture-proof as what you see under the hood of a modern car.  I could very well be wrong on this, however. 

-It should be pointed out that MZ-b uses Vape electrical parts in their systems.  MZ-b specifies the timing curve and does the packaging, marketing and distribution.  I have no idea who makes the basic alternator assembly for Vech. 

-Both systems can be converted back to "original", should the desire arise. 

From: "Wolter, Klaus"

Date: Wed Feb 5, 2003 2:28 pm

Subject: RE: [slash2] Re: 6v battery and the MZ electrics

Your Motorrad Elektrik alternator conversion kit is more conventional and is just like what is used on most cars.  The ignition coil that comes with your MZ-B 12v electronic ignition conversion is not the same as the ignition coil that comes with the system that includes the alternator.  Your system is dependent on the battery being able to supply enough current to fire the sparkplugs when you try to kick it to life.  If your battery is dead, there will be no spark.  This is not the case with the MZ-B system that comes with the alternator.  Your Motorrad Elektrik alternator is not very similar to the MZ-B alternator.  Your alternator has no permanent magnets, like the MZ-B.  The regulator on your alternator controls the charging current by controlling the intensity of the magnetic field, inside your alternator, electrically.  The MZ-B can't change the magnetic field inside it's alternator.  It's fixed because it uses magnets instead of an electromagnet.  Magnets, in the MZ-B alternator, allow it to generate a spark without a battery, just like the original BMW ignition. 

From: Joel Rapose

Date: Jan 2003

Subject: MZ-B Electronic conversions

I now have in stock 6 electronic ignition/alternator conversions available for immediate shipment.  I decided to sell the kits after waiting 5 weeks for my original system to arrive from Europe (economy shipping) So I made an agreement with MZ-B to be the Distributor for their kits in the USA. 

I really love my kit, and I have been distributing systems for about a year...I carry all the spare parts in stock so I can ship anything by bus or air if needed. 

The prices are the same as on the web site...  I do charge for European

shipping to me...but I buy 6 at a time and ship economy so it is only

$14.40 per kit. 

This is a SUPER conversion 12 volt alternator and Electronic Ignition...  trouble free...does away with the points, advance mechanism, magneto, generator, regulator and replaces it with a neat clean modern system...using modern motorcycle parts..all hidden under the tank...  even comes with new plug wires..it is really complete, stainless steel mounts, all the connections are made up....the total installation takes less than several hours....and it's easy...  I am also available by phone to answer any questions.  805-987-1750

The complete alternator (12volt) and ignition price is 301.72 euros $322.24. 

Shipping from Europe is $ 14.40. 

The special alternator puller tool is (I highly recommend) $ 12.82. 

USA shipping to you is $ 8.00. 

Total is $357.46.  This changes with currency conversion changes

Added in later msg:

There are two different crankshaft taper sizes, early bikes, up to about 1960 had the smaller taper and the later bikes had the larger.  Yes, I do stock both and if you order the wrong size I keep a spare just for exchange.  Installation of the kit only takes about 2 hours.  You will need a 12 volt battery but everything else is in the kit...also you will need to get the alternator removal tool they offer...it's something like $12 ...The new alternator has a large bore where it attaches to the crankshaft and without the tool I don't have a clue how you would ever remove it if you had to...also I found out that if you have a bike with a damper, like a R69S the nut from the alternator tool works as a perfect mounting flange for the damper, even better than the original. 

Joel Rapose

Camarillo Calif

Note by Duane, it takes far longer than 2 hours to install the Mz-b system.  Joel and I did one together and it took us over 2 hours.  One also needs the 12 volt bulbs. 

More info about fitting the Mz-b alternator

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