Rule change submissions close 1 March 2016 - be in to win.

[FastFred]

Someone told me old skid mark was an arse but I'm not him I promise ....

Talks the same ... what smells like a duck, walks like a duck, quacks like a duck, I promise you, it may very well be a duck.

[FastFred]

You are sort of faced with two choices, do the work or try and cut down others successes by fiddling with the rules.

Owners of already developed 100cc water cooled 2t bikes could say that. They are getting no benefits at all from the rule change proposals where as pretty much all other types of F4 engines are.

Not sure how a proposal that is adding clarity by better defining a 24mm carburetor equivalent technically disadvantages or benefits anyone. If I have missed something please point it out.

[jasonu]

Not sure how a proposal that is adding clarity by better defining a 24mm carburetor equivalent technically disadvantages or benefits anyone. If I have missed something please point it out.

Has talk of proposing removing the 24mm carb restriction for 125cc aircooled 2t AND adding a 24mm carb restriction to over 104cc watercooled 2t been abandoned???

If that is the case then it looks like skid mark is not the only one with comprehension issues...

[FastFred]

Has talk of proposing removing the 24mm carb restriction for 125cc aircooled 2t AND adding a 24mm carb restriction to over 104cc watercooled 2t been abandoned???

I have been following this with interest, and things do get a bit disjointed, the idea may have been floated. But pretty sure the 24mm restriction for any 2T over 104cc is currently in the rules and its just the clarification thing of what a 24mm equivalent means. Or better yet now 100's can be 110cc removing the restriction all together for everyone as air cooleds are more effectively thermally limited than they are by a 24mm carb. Anyway that is the way I understand it.

[Moooools]

Rule:
Down-stream of all throttling devices, a SINGLE restrictor with a maximum internal chord length of 24mm, OR, TWO restrictors with a maximum internal chord length of 17(?)mm must be implemented. All air entering the engine(s) must flow through the restrictor(s).

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If you can't remember your high school geometry: https://en.wikipedia.org/wiki/Chord_(geometry)
Pretty much, it doesnt matter what shape it is, if you can measure more than 24mm (or 17mm for two) anywhere arross the smallest section of the restrictor, the rule has been broken. This restrictor could of course be a part of the carb, as long as it is down stream of the throttle (buterfly/slide/whatever

Sure this leaves it open to making massive plenums down stream of the carb, but have fun with throttle response if you start plaing that game. Also oval carbs might get a little shafted, or someone might want to build a triple, but hey, you can't please everyone.

[Grumph]

I think this is worded just for your own needs, maybe it would be better and fit the purpose for which it was intended if it read
F4 2 stroke engines over 104cc ; At some point in the inlet tract(s) between throttle slide or butterfly and crankcase or barrel, the inlet tract(s) shall not exceed an area of 452mm2 (24mm equivalent) in total. For the purposes of measurement, EFI throttle body idle air circuit if any and carburettor air bleed jets and orifices shall be ignored.

Oh for fucks sake, how about a compromise.

F4 2 stroke engines over 104cc: At some point in the inlet tract(s) between atmosphere and crankcase or barrel, but within the confines of the carburettor body or Injector throttle body(s) the inlet tract(s) shall not exceed an area of 452mm2 (24mm equivalent) in total. For the purposes of measurement, EFI throttle body air circuit if any and carburettor air bleed jets and orifices shall be ignored.

[mr bucketracer]

On the topic of capacity and older style engines (such as 2 valve 4ts), it's worth looking at the Australian NSW bucket racing rules as they've done just this.
They split it into motolite, commuterlite and superlite. Motolite being the more modified class which is open rules on frames etc. Superlite is pretty much stock bike racing. I don't think we need 3 classes but there is definitely scope for 2 classes which are raced on the same grid as we do currently. That is, F4 and F5 grids but with two sub classes.

I really like this set of rules. It's super simple and not a bunch of crammed together sentences with poor grammar pretending to be rules.

CLICK HERE FOR FULL RULES

2014 Motolite Rules
Classes: One class combining:

- 111cc Air-cooled single cylinder 2 stroke
- 159cc Air-cooled 2 valve twin cylinder 4 stroke
- 175cc Air-cooled 3, 4 or 5 valve 1cyl. 4 stroke
- 190cc Air-cooled Horizontal 4 Valve 4 speed
gearbox (Laydown Motor)
- 230cc Air-cooled 2 valve single cylinder 4 stroke
- 85cc Water-cooled 2 stroke
- 159cc Water-cooled 4 valve single cyl. 4 stroke
- 185cc Water-cooled 2 valve single cyl 4 stroke

i agree with most of this if weight limits put in place

[F5 Dave]

OK how about this, everyone else starts and you have to weight at least a lap?

[mr bucketracer]

OK how about this, everyone else starts and you have to weight at least a lap?

2 laps to give you guys any chance , going to bring a divers belt to the track (-; who wants 60kg added to there weight

[FastFred]

LOL looking back over this thread it is amusing to see people who think that cleverly modifying a 2T cylinder is a perfect Bucket thing to do but when it comes to cleverly modifying a carb or inlet system within the rules they get all worked up as if it was somehow cheating .....
Cleverly modifying a carb or cylinder or anything else to get the best out of it, its all a perfect Bucket thing to do.

[Yow Ling]

LOL looking back over this thread it is amusing to see people who think that cleverly modifying a 2T cylinder is a perfect Bucket thing to do but when it comes to cleverly modifying a carb or inlet system within the rules they get all worked up as if it was somehow cheating .....
Cleverly modifying a carb or cylinder or anything else to get the best out of it, its all a perfect Bucket thing to do.

Yea , if you can modify your carbs , we want an extra 30cc !!

[TZ350]

Yea , if you can modify your carbs , we want an extra 30cc !!

See you and raise you one. You can have 30cc if we can have nitro to play with too ......

[husaberg]

See you and raise you one. You can have 30cc if we can have nitro to play with too ......

I was actually thinking the other day about a 180 degree u turn.
Just Maybe it is time for MX 80's but only if they are cylinder reed that gets rid of the potential flash harrys that would turn up on 2013 KTM85 engined bikes.

[Yow Ling]

Just have a "no flash harrys" rule

[husaberg]

Just have a "no flash harrys" rule

But i would really like to do it myself.