As the riding season in New England draws to a close I'm finding time to catch up on this season's WSBK racing (thanks to the DVR). Thought I'd throw out a topic for discussion - weight minimum's for WSBK bikes.

I know some of the members on our forum have seen substantial drops in weight on some of their project bikes but I'm amazed at what it must take to get a production based 1K street bike < 360 lbs. Once the usual big items are subtracted out ( lighter rims, exhaust, lights and display, etc) I would imagine it's a more a matter of ounces or grams at a time instead of pounds at a whack. Assuming the production bike started at 450, the last 30-40 lbs must be pretty expensive to get to.

I recall from years ago (before carbon fiber) race car teams would go to crazy lengths to lighten the car to include acid dipping the body to thin the metal. I'm not suggesting anyone would try a stunt like that with a bike, but anyone have insight into how they actually get to those low numbers on the bikes? Is it wholesale replacement of parts with Ti parts or what? Any of you guys have experience with what goes on in those shops?

Again, just looking for something to chat about.

Cheers.

 

I had never heard of thinning the metal, but I have heard of them doing the acid dip to remove excess paint and body coatings. On the matter of the weight reduction on bikes...
If you open up most modern engines, there are some significant weight reductions just in part replacement with race parts as well as machining. Here are some areas of reduction:

Valves, pistons, connected rods, porting, emissions items, flashing on engine parts, etc.
these dont seem like much but it really adds up. If you go through the whole machine like this, it just keeps compiling into the figures that they end up with.

 

I could see where hogging out some materials on internal parts could drop the weight as the parts aren't expected to last years. Even so, it is amazing considering the stress the parts are subjected to for the duration of the race.

Re: thinning metal
IIRC, Chevy (Henry “Smokey” Yunick) got into the act by dropping body parts off the cars into the acid tank. You could feel the body panels flex in by just putting a little pressure on them. Wild stuff.

 

As a Vocational Automotives Instructor, I got to tour a company in Fountain Valley, Ca called "Metalcrafters" a few years back. Their main business is building concept cars. But they also build funny car bodies for John Force. They have a giant autoclave that an entire funny car body fits into. The autoclave sucks the resin out of the carbon fiber, resulting in a funny car body that weighs 82 pounds.

 

That should give an idea of how much they lose off the body work, and how much they lose off each part they replace with lighter/stronger materials like mag, ti, and carbon.