I don't understand how the builder of a bike has a responsibility to the club to only build legal bikes. Isn't that like saying that a gun manufacturer is responsible for a drive by shooting?(or would that be the car manufacturer?) They both just supply a tool, how that tool is used is up to the person who purchased it. I feel that if a shop or person is building a race bike, and they know what class it is going to be raced in, they have a responsibility to the customer to know (or find out) what is legal for that class. If the customer insists on the bike being built to be illegal, whatever moral issues exist about cheating now fall on the shoulders of the customer. The shop is being paid to provide the best work and parts that it can. How that is used is up to the customer.
In our short time being involved in racing (3 years) we have definately ran into people cheating (yes, a kx100 looks exacly like a kx85 if you take the factory graffics off). We barely have enough money to race, let alone put up money for protest fees or build our own cheater bike. We had no choice but to race against that person anyway, and yes we did beat that person more than once. I have to agree with Cromer, it felt great!
Cheating to me is all about personal integrity. Some people have it, and some don't. The ones that don't sure are fun to beat!
From where we stand, we are looking at joining the 250 production class with a bike that we have $450 invested in. We will be racing against people with 10 to 20 times as much money wrapped up in their legal bikes and god knows how much wrapped up in illegal bikes. It doesn't really matter to us if they are making 2 or 3 or even 10 more horsepower than we are. The important thing is to teach my kids that they don't need to cheat, they just need to work hard with what they have available to them, which isn't much and probably never will be.
Ok, now for my possibly constructive part, what about random bike inspections? Kind of like random drug testing at certain jobs. Pick one bike at random each race and tear it down. If everyone who enters pays a small fee of say, $2 or $3 it should cover the cost. If you are found legal you get the dough to put your bike back together, if you are found to be cheating you lose all points, cannot race that class for the remainder of the year and have to put your own bike back together. The thought would be the same as a random drug test. Fear of being caught at random should make everyone want to be legal at all times.