How & Why: Motorcycle Charging System DELETE

I couldn't resist an old 2nd gen GSXR750 that popped up on Craigslist back in 2016.

It didn't come with a clear title (or a fuel tank, or bodywork, or fairings/plastic, or a bunch of other stuff), so the plan has been to turn it into a track day bike.

I used to road race and do track days back when I had more time and money. I'm kinda sorta over racing (I'll never be truly over racing! NEVER EVER!!! I still race dirt bikes! That counts RIGHT?!), but I like the idea of having a cool bike capable of doing fast laps at the track. The older the better. I wanted something with cooling fins on the engine, carburetors, and wrapped in fiberglass fairings.

Enter the dragon... an '88-'92 Suzuki GSXR750.

The frame came from an '89 bike. The subframe from a '91 bike. A Katana 750 donated its engine. The wheels and suspension are from a '91/'92 bike. It's kind of a "bitsa" considering all of the parts I've had to buy for it.

Anyway, on to the charging system delete. What the heck is that? Why would I get rid of it? What are the pros and cons?

Most motorcycles have some kind of electric starter attached to them. A battery powers the electric starter. For the battery to work the way it should to start the bike, it has to be charged somehow while the bike is running. Enter the "charging system." Most charging systems consist of a stator and a rectifier regulator. There's a flywheel/magneto attached to the engine's crank. Electricity for the battery is produced as the flywheel spins around the copper windings. The rectifier/regulator keeps the voltage down to <14.7V to charge the battery.

Old GSXRs have a weird charging system. It's basically an automotive alternator bolted to the engine. Check this turd out:

That's the GSXR's alternator on the left. There is no rectifier/regulator, or rather it's built into the alternator. My bike's alternator didn't work. Because it's a track bike, I figured I'd just get rid of it. Because the bike has carburetors (and no lights, or anything drawing electricity other than the CDI box), it'll run for a really long time without having to charge the battery. It's a track day bike. This isn't something you'd want to do to your average street bike.

I had already built a custom wiring harness for the bike. I like to throw wiring harnesses in the trash and build my own! It's fun!! I figured I'd add wires for the charging circuit if the alternator worked. The alternator didn't work, so that got thrown in the trash too!

I needed something to put in the alternator's place, otherwise the engine would have spewed oil everywhere every time I started it. LOL. Enter APE Racing, GSXR etc parts extraordinaire. They make an "alternator block off plate" that fits all of the old skool oil-cooled Suzuki engines. It's on the right in the above pic, but here's a closer look at it:

Kinda takes you back to the early 00s eh? Look at all that shiny billet aluminum!

Installation is pretty straightforward. Start by finding the alternator:

There it is! Now unbolt that ish!!!

POOF@!!!! Disappearing alternator!!! Next step, lube the block-off plate's o-ring and bolt it to the engine!

Notice how there's an unused mounting hole at the top there? I'll grind that off the next time I have the engine out. The block-off plate uses just two fasteners in place of the alternator's three. APE says most drag-race folks grind the top mount off to make space for bigger carburetors. I'd love me a set of 36mm Mikuni RS carbs, but they're out of my budget at the moment. Not that they'd do a hell of a lot of good attached to an old Katana engine, but they sure as heck look cool!!

Easiest install ever. I got rid of a totally useless 5lbs of sprung weight and removed a rotating part from the engine assembly. That means MORE POWER!!! LOL! The bike's already going to be faster than I ever will be, even though it's nearly 30 years old, probably weighs close to 400lbs, and might have a whopping 80hp at the wheel. I'm not terribly concerned about making the bike faster or lighter. I just didn't want to buy a working alternator; removing it and installing the block-off plate was cheaper and easier. And because this is a track bike, it's totally appropriate.

Now if I could just find a way to remove the starter and start this old GSXR on rollers or with a drill/starting tool... That'd be really trick and super cool... LOL!!

Again, these aren't mods you'd want to do to your street bike. It'd be retarded as all hell to ditch the charging system on a street bike, but for this application it'll work just fine.

Stay tuned because my wheels are at the powder coaters', and I have a set of brand-spanking-ass new Bridgestone RS tires to go on them when I get them back. I have new brake pads and levers and the forks don't leak, so it's only a matter of time before I post pics of what I look like at 135mph on the back straight at HPR. LET'S GOOOOOOO!!!!!

And a pic of yours unruly after I finished installing new oil lines on my van:

STAY GRIMEY MOTO FOLKS!!!