I've read the rules, and for my '85 GPz550 running in Super Dinosaur, is the bore size limited? Unless I'm reading 6.1.2.e wrong my bike doesn't fall into "Open cc" and it's 1mm overbore limitation, or does it?

Then reading further into the rules, I see this:
8.1.1.c "Cylinders may be bored to a maximum of 1.0mm over the bore size corresponding to the class displacement for a given stroke in Formula, Grand Prix, and Superbike classes."

Read 8.1.1 c . If you overbore your bike by 1mm it would be approx. 574cc if I did my math right.

you beat me to it. 1mm over is allowed.

Thanks for the reply Ed. 1.0mm overbore pistons would have to be custom made, but 3.0mm overbore pistons are readily available. Oh well...

Hi Ed,
is the limitation just because it is a "super bike" class? I mean, it doesn't seem to really matter much since it's such a stew pot of bikes. It doesn't seem it would matter as he'll be up against 600's, 900's, etc, and, well, it's a Kawi....

I can only race in Super Dino, and Formula 40 Lightweight.

Dave,

All classes, except production where overboring is not allowed, have a maximum 1mm overbore limit. Read 8.1.1c. Though you do have a point Dave. He could overbore it 3mm as the class has no displacement limit but it would put the bike into Formula 40 heavy as it would now be about a 613cc motor.

Thanks Gents. I'll just keep it stock bore for now.

Tazman wrote:Dave,

All classes, except production where overboring is not allowed, have a maximum 1mm overbore limit. Read 8.1.1c. Though you do have a point Dave. He could overbore it 3mm as the class has no displacement limit but it would put the bike into Formula 40 heavy as it would now be about a 613cc motor.

Ed,
you are confusing class displacement limits between open class and other classes. rule 8.1.1c. refers to class limit and not to OEM displacement of individual motorcycle. only open cc class has limit on OEM displacement for bikes that are legal for class as stock, all bikes 751-open that fall in this class can only overbore 1mm. however all bikes that fall in smaller than this class by OEM displacement are allowed boring and stroking up to class limit where they will race (same for formula.gp and sb bikes).
so, if your original bike displacement is lower than 751 your bike belongs to 601-750 class (there is twin and single allowance which I am not going in to now) and by boring it out 3mm it automatically becomes illegal for 601-750 class and legal for 751-open class. but since it was not 751-open bike to begin 1mm overbore rule does not apply to it.
in case of superdino this rule does not apply at all since displacement is unlimited and there are no classes by displacement, it is class for itself.
By your interpretation no bike there is bored more than 1mm or stroked would be legal in any class except FP. Lohmayer 450 or sv500 would not be legal to race in any class, those are just two as example.
this is because rule 3.1.1c is same for formula or sb or gp class and only excludes production classes where there is no overbore or stroking at all.

I see, so my bike fits in 6.1.2 Superbike 451-600cc, for Super Dino and that would allow me to bore/stroke, not to exceed 600cc then, right?

correct for 451-600 class. you can bore more but than you are not legal for 451-600 class. you still legal for superdino and 601-750sb.

in other words you can bore and stroke your 550 to any displacement you want (3000cc) and you still legal for superdino. but if you want to run any other class you have to meet that class displacement limit + 1mm max.

The only other classes I would run in is F40 Light or Clubman.

553cc plus 2mm overbore is 592cc.

F40 lightweight covers many classes. pick the one that will give you biggest displacement that you can fit in and that is what you need to meet. on top of that you have option to go 1mm over written class displacement limit for your stroke.