ALPHA Ignition System 1981 through 1995 Airhead Twins
All-new Hall sender "bean can" with external module for digital advance control-no more sticky spark advance parts inside!
Update! Dual-plug version is now available! Call or e-mail for for details and ordering.
The original Hall effect electronic ignition system fitted to the BMW twins from 1981 through 1995 was far from optimum, even by 1981 standards. By this time, digitally controlled ignition systems were common on autos and motorcycles. BMW continued to use a "half-way house" electronic ignition that relied on mechanical bob weights and springs to control the spark advance curve , all the way to the end of production in 1995. Mechanical spark advance control is not necessarily bad, unless it is non-serviceable which was the case with the parts BMW used. The marginal internal lubrication of the moving parts tends to go away after some years, very often resulting in a sticking advance unit and worn pieces. This was usually evidenced by the idle speed sticking at 1500-2000 RPM or hard starting.The ignition Hall sender unit did not evolve or change one bit in 14 years. The price DID evolve,ever upwards, to the current (Sep. 09) price of $514.49 !
This high-quality Hall sender system is an exact replacement for the original parts on all 1981 through 1995 Airheads.It plugs in to the original ignition control unit already on the motorcycle, and requires NO modifications or rewiring, with no need to change the original coil(s).Bolt it on, plug it in, and set the timing-nothing difficult for the home mechanic.
All of the housing parts are CNC machined from billet aluminum. The short,rigid steel drive shaft is supported on both ends by SKF ball bearings, which are held in place by common circlips. All O-rings, seals, and bearing seals are made of high temperature Viton material. All the fasteners are stainless steel socket head screws.
Installation is a breeze, since all the electrical connections are straightforward, easy to identify,and practically impossible to connect improperly. Except for a strobe-type timing light, just a few hand tools are all that's needed. Timing fine tuning is done just like the stock system-use a strobe light, turn the can till the marks align.
The timing specifications are basically
the same as the factory settings except for a slightly higher
max advance rpm:
Idle speed timing : 6 degress BTDC
Advance begins : 1400 RPM
Advance ends : 3400 RPM
Maximum advance: 22 degrees BTDC
Total range of advance : 28 degrees
NOTE: These specifications are intended for a stock, single spark plug per cylinder engine. A new module that provides control optimized for a twin-plug ignition will be offered in the near future.
The solid-state ignition advance control module is about the size of two standard cube relays, and is easily mounted at some convenient location under the fuel tank.This wonderful little black box will once and for all remove the troublesome chronic sticking mechanical spark advance problems of the original part. This routinely causes either hard starting or very fast idle speeds that will not drop . Digital control of the advance curve assures that it will be ultra precise and provide consistent timing for both cylinders that results in a very smooth power delivery.
The actual Hall sender device is the same Honeywell 2AV54 sensor that is used in the original part, as well as in many automotive applications. This unit can be bought widely at electronics supply companies for less than $20.00 , which is also about the price of a pair of the bearings. In the event of a need for service or repair in the future, it will be very easy and inexpensive for the average owner to completely renew the Alpha ignition. This unit was designed intentionally to be easily rebuilt with minimal tools. The connectors are common spade terminals that can be renewed easily if ever needed.
The quality,performance,and value of this new Alpha ignition system makes it one of the best ways to modernize or repair your Airhead for the long haul ahead-something you've come to expect from Motorrad Elektrik.