Superbike rules & twin cylinder motorcycles.

Starting to get things in order to get back into Racing. Scoped out the current rule book and notice a rule had been omitted.

I believe it used to be legal to build a single or twin cylinder bike to Formula specs and still be legal to for Superbike.

I only ask as my '96 ninja 250 has a ninja 300 engine in it, and that exception allowed me to not only be legal for SBK, but also stay some what competitive. Was this something that was purposefully removed or just seemed like an antiquated rule that affected no one?

That rules was for twins running down class by using their own rules. I think 250 class was excluded so that rule would not apply for what you doing.

This was from the 2014 rulebook and I speak of 6.1.2(9b) Was it voted upon to be omitted, or just removed?



6.1.2 SUPERBIKE: Superbike Rules apply (ref. Section 9.2). Production-legal bikes may also run in Superbike classes. Each of the following displacement categories is a class:
175-250 cc
251-450 cc
451-600 cc
601-750 cc
751-Open cc
a) The following 4-strokes may run down one class in Superbike: Singles,
Twins and 675 cc triples.
b) 4-stroke Singles and Twins may be built to either Superbike or Formula rules.
c) Water-cooled twins are limited to a 250 cc displacement advantage when
running down a class.
d) 600 cc and 750 cc class bikes may run up a class.
e) Openccbikesarelimitedtostockmanufactureddisplacementplus1mmoverbore.
f) A “3/4 600” (a 600cc four cylinder modified as a 450 triple) may run in
450 Superbike with a maximum functional displacement of 450cc. The 4th
cylinder must be permanently disabled. Rule 8.1.1c does not apply.

Hi Joshua,

I would do your brain a big favor and at least start reviewing the 2018 rule book https://www.afmracing.org/documents/afm_rules_current.pdf

There have been several major changes since 2014. Keep us posted if this doesn't answer your questions.

I can save you some reading and let you know that your bike is not Superbike legal.
Engine cases and frame have to remain the same as it came from the factory.

I understand that it is currently not legal for SBK. I read the rule book, that is why I am asking this question.

My question is what this omission done purposefully by a vote or just left off as it was felt it did not apply to modern racing?

My follow up would have been, Id like to re-instate the rule, but I seen I have missed the window. I guess I'll wait till next year to bring it up.

It was removed as there were efforts to utilize this rule to build one off motorcycles and then race them in a production based class.

KazMan said:

It was removed as there were efforts to utilize this rule to build one off motorcycles and then race them in a production based class.

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That rule applied for superbike based class only.

By production based, I meant street legal based motorcycles vs one off race framed motorcycles with dirt bike engines, or other.

KazMan said:

By production based, I meant street legal based motorcycles vs one off race framed motorcycles with dirt bike engines, or other.

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No formula class required street legal motorcycles. Even SB was limited to minimum somewhere in world.
Formula twins classes had many of this bikes in past and reason for rule, so they could race in sb classes.

And in an effort to keep production based classes somewhat cost effective, it was an effort to get back to standard baseline configurations. There was a time from 2000 to 2010 where there were a lot of custom bikes that were truly formula bikes by the rules. The numbers of these bikes is down to about 2 with most being true superbike builds now.

KazMan said:

And in an effort to keep production based classes somewhat cost effective, it was an effort to get back to standard baseline configurations. There was a time from 2000 to 2010 where there were a lot of custom bikes that were truly formula bikes by the rules. The numbers of these bikes is down to about 2 with most being true superbike builds now.

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2 if you don't count cripples which are basically formula bikes.
Just because it does not cost much to convert it does not make it much different than putting 300 engine in 250 ninja frame. Neither are production, they are formula bikes. So, why would one formula bike be legal for SB and other not?
That is exactly reason rule was changed back than, so they all can play same game.

Putting a smaller engine in a highly advanced fame (like cripple 450) gives an advantage. putting a bigger engine is a lighter frame also gives an advantage. Though they are opposite sides of the coin, they still are both Formula derived builds.

If getting a higher quantity of bike participating is a goal, then give both these types of bikes considerations in Superbike.

Every other CLUB racing Organization in the Country has this Rule still written into their class structure.

6.1.2B

Im glad someone else took notice.

The rule did only apply to SB NOT superstock Or "production"
The AFM could really pick up a few more bucks from its existing paddock and after 7 rounds of entry that chunk of change could be significant. Just by re inserting this sub text

I agree. there are so many old race bikes out there that can be resurrected and competitive with rules like these in place. The Legacy classes are a great thing, but I feel most riders want to be on track as much as possible. Plus bigger groups make for some amazing racing.

I couldn't agree more, but there are a few folks in the AFM who decided that the correct agenda for the club was to stack the deck in favor of the current crop of 350 prod legal bikes. Not only was 6.1.2B deleted, but the 300WSS class was added. There was also a preiviously allowed interpretation of the rules that a few people used to run singles down into a lightweight twins formula class...a decision was made to disallow that. Admittedly a grey area, but the singles would not have had an advantage over a true formula twin in that class...only over the prod bikes that currently fill it.

Don't get me wrong, I love that the 350 prod bikes have tons of classes to play in, and I think it's a great platform for many racers (myself included). It's just that the decisions made were done to make those bikes competitive in classes that they really have no business being competitive in. If anyone brought true 250sb legal race bikes or built true formula-based lightweight twins, a decent rider on those bikes would decimate the prod bikes and then the folks with the agenda would figure out a way to tighten the rules or change the class structure again.

One of the things I always loved about the AFM was that there was a place for all the unusual/interesting bikes. It's becoming much less so, and I mourn the loss of some of AFM's soul. I still think AFM is an amazing club with great people, but there are definitely some agendas at work that aren't necessarily the best for the club as a whole.

All that said, I don't have a horse in this race since I'm no longer racing.

ILOAD2 said:

Every other CLUB racing Organization in the Country has this Rule still written into their class structure.

6.1.2B

Im glad someone else took notice.

The rule did only apply to SB NOT superstock Or "production"
The AFM could really pick up a few more bucks from its existing paddock and after 7 rounds of entry that chunk of change could be significant. Just by re inserting this sub text

Click to expand...

I would disagree, a member brought back out there TZR 250 superbike legal bike based off a production frame and won the class handily before putting it back in the shed. It was built to the rules of the class which start at the introduction to either Superstock or Superbike.

Formula classes are in existence for unusual/interesting bikes with pretty much anything goes and class being dictated by the engine displacement. Have a one off frame, that would be Formula based bike. Have a frame that was manufactured and distributed for street use available from a dealership world wide, that's a superbike.

Those most basic rules, the introduction to each class explaining where a motorcycle originated from, have not been modified.

And we do miss you on the grid.

KazMan said:

I would disagree, a member brought back out there TZR 250 superbike legal bike based off a production frame and won the class handily before putting it back in the shed. It was built to the rules of the class which start at the introduction to either Superstock or Superbike.

Formula classes are in existence for unusual/interesting bikes with pretty much anything goes and class being dictated by the engine displacement. Have a one off frame, that would be Formula based bike. Have a frame that was manufactured and distributed for street use available from a dealership world wide, that's a superbike.

Those most basic rules, the introduction to each class explaining where a motorcycle originated from, have not been modified.

And we do miss you on the grid.

Click to expand...

The example you site is from NINE seasons ago (9)..The rider was well know in the motorcycle community to have VAST financial resources..He was never protested so his championship was certified as legitimate. It would be better to take inventory of TODAYS paddock make up-and gather those extra entries into our existing classes. I believe on this particular instance your "class Destroying" fears are entirely unfounded. Every other Racing Organization in North America recognizes that singles and twins have an inherent Disadvantage in performance hence the allowance to run under formula rules. The AFM had this rule in place for 30 Seasons Prior to the striking of it from the book..It is clear there are no vast custom builds waiting in garages for the rule to be returned- just folks waiting in the existing ranks of regular attendees waiting to pick up more classes. It really makes no sense to not put 6.1.2B back in the rule book for 2019.

Grease_Monkey said:

I only ask as my '96 ninja 250 has a ninja 300 engine in it, and that exception allowed me to not only be legal for SBK, but also stay some what competitive. Was this something that was purposefully removed or just seemed like an antiquated rule that affected no one?

Click to expand...

Did you ever get an official ruling on this? Superbike legal? Which class? Or Formulae only? Thx

This year, my bike is only legal for formula classes. Mainly competitive in FIII and Formula Twins (under 500cc). Im not competing, but when I do plan on racing again, I will make sure to petition the reinstatement of this rule, or a variation of it.

I enjoyed racing in the SBK class and Im sure the AFM enjoyed my entry fee to participate in it.