Since the inception of the SV650 in 1990 the bike has come a long way. When it was first released, the bike made approximately 70HP, not a monster but certainly good enough to get it down the freeway at reasonable speeds. The picture below is the result of racing on the stock crankshaft, stator and rotor.

At first, we all stepped back and said, I wonder how that happened? I started looking closely at how much the stator and rotor weighed along with all the starter mechanism and came to find that it weighs in at what I think is pretty heavy 2300 to 2400 grams. That's just over 5 pounds. Now on the stock motor with stock power pulses this is not a big problem but as soon as you start screwing the motor down and getting over 85 to 100 hp, it becomes a big problem. Every time the piston fires, the crank shaft will try to accelerate. The rotor, being a rather large heavy mass, especially at 8K - 10K RPMs is countering and trying to stop it. With enough stress cycles (accels / decels) the crankshaft, having that little stress riser of an oil supply hole, becomes a sacrificial part. As we know, when the nose of the crank breaks the ignition rotor loosens and goes into the charging coils, usually wiping those out. In really bad cases, it takes out the ignition as well. At that point, you're looking at replacing the whole motor.

After looking at all of this and talking with some other tuner friends of mine, we came to the conclusion that there is considerable weight to get rid of on that ignition rotor setup. Starting with the huge one-way roller Sprag-clutch assembly, it alone weighs in at approximately 626g.

Certainly we could get rid of some weight here.

Here is a picture of the roller Sprag assembly after being cut on the lathe (left). Next, we put it in the CNC lathe and took even more weight off of it (right).  We went from 620 + grams to 302 grams. A significant drop in rotational mass.

Then, the rotor itself is almost a quarter of an inch thick; certainly we could lose some weight there. We take almost .100 off the circumference, leaving the ignition triggers (bottom).

Lastly, the magnets that run the ignition, do we need all six? Well, for the hard-core SV racer where less is always more, we have found over the last couple of years that we really only needed two magnets to keep the charging system functional. The race bikes don't have lights, turn signals, handgrip warmers or any of that other stuff to run. If all we have is the ignition system (and in the second GEN the fuel pump), two magnets work just fine. So, if you have had problems with crank breakage on your SV, or you've seen the carnage done by a broken crank on your buddy's SV and you'd like to try and avoid it, this is the solution. We've got a good reputation for making good horsepower and durability with our motors. This is one reason why. Thanks for reading and let us know if we can help.