Product Description
Kawasaki ZXR400 Race Generator kit
This is the complete race generator kit including the lightweight flywheel, stator, mounting plate, cup fasteners, connectors and specific regulator / rectifier.
Now with a larger magnet fitted to ensure that battery condition remains as good as possible during the race.
Significantly lighter than standard, offering higher output than 'race kit' versions, providing increased throttle response,less gyroscopic forces and more bhp everywhere. It is designed to fit high performance injection engines, and as a replacement for standard alternator systems.
Typical gains on a standard bike are around 3bhp and generally the higher the state of tune of the bike the greater the gain - see an example dyno run in the item pictures.
This state-of-the-art alternator uses a tiny 80mm diameter rotor (most of which is a thin flange - see pic), weighing only 294g. This significantly reduces the effective weight of the crank by not only reducing the weight of the rotor by 75% from 1210g, but also by reducing the radius over which this weight acts. Standard rotors are around 120mm in diameter (compared to ours at 80mm), so the speed of the edge of the rotor is much higher - for example at 14000 rpm the standard rotor edge is travelling at 200mph, our rotor edge is only travelling at 130mph. Anyone who's tried knows that it takes significantly less time and effort to accelerate up to and stop from 130mph than it does from 200mph in a vehicle 4 times the weight; this translates to much improved throttle response and faster acceleration.
'Total loss' systems have always been popular with carburetted bikes when racing. What most people forget is that the coils on motorcycles are merely multipliers of power so the less power you have in your battery the less fat the spark. This can lead to a significant reduction in effective combustion throughout the course of the race.
Another factor which has influenced the effectiveness of race generators on carburetted bikes has been the popularity and affordability of lightweight lithium batteries. These offer a great weight saving over gel or lead-acid batteries and have much greater cranking power than other types but they do not have anything like the 'legs' of lead-acid or similar running flat much faster. This combination means that a lithium battery rated much lower than recommended for the bike will have sufficient cranking power as well as even less weight but to last well during a race they need charging during the race. This means you can get the weight saving required to add a lightweight generator system without gaining overall in terms of static weight of the machine and still have a consistent, fat spark all the way to the end of the race.
The standard alternators are designed to run headlights etc and need to be able to supply significantly more power than you will ever need on a race bike. This means you can use a considerably smaller system such as this, reducing the weight of the crankshaft assembly.
Most race kit generators have a smaller rotor with less windings in the stator so that they produce less outright power (and accordingly take less power from the crank to generate the electricity), and use a standard reg/rec.
The problem with this is that you have to rev the engine quite hard to produce any useable power and any excess electricity created is still converted to heat in the reg/rec and thrown out the back of the bike.
Our generators also use a small rotor but our windings have a lot of turns of fine wire. This allows us to provide strong and consistent power at lower revs, but the clever part is in the reg/rec. The reg/rec contains a switching system which cuts the generating power when the desired voltage is reached and therefore the power is not taken from the crank to convert to electricity in the first place. This is why our reg/recs run much cooler than standard models and why you cannot use our generators with a standard reg/rec as the generator would be under load all the time creating excessive heat in the windings.
Please note BDK race generator kits are for racing purposes only and not designed for high draw systems with lights etc. (road machines). The kits are designed with performance riding in mind and will not charge below approx. 4500RPM, this is the trade-off you get for more power elsewhere.
