Box Stock

akra rule on butterfly to throttle shaft screw ?

C

conehead

New member
what is the rule on this little screw that holds butterfly to throttle shaft? im sure its something like must remain stock or compared to stock ......but is there a min length or any tolerances on this screw ? thanks jack
 
You should probably look "Spirit and Intent" in the eye on 'this' one! I don't 'thick' the 'book' specify's the screw parameters, but it does speak of modification no-no's. I've seen some screw's smaller than others and wud not hesitate swapping them around, but...I ain't gonna start grinding on them! (Assumed 'Box-Stock' Only) jmo
 
Screw must remain stock. No cutting, grinding or filing of any kind allowed. No length rule, but if you shorten it you better be able to cover it up.
 
Bryan / Don or, any 'tech'.......(similiar arena) except "S & I" doesn't apply becuz of 'Keyway' / Non-Tech status, However....If I 'machine' a relief in my Coil mtg bolts that wud allow abt 5* of 'fine' tuning timing, would I be DQ'd....becuz I 'machined'...filed or otherwise, a bolt? (it's a 'convenience' issue....Not Performace related!)
 
the reason I asked the question was I see differences in the lengths of the ones in the carbs I have ,,,,,, just gonna go with the shortest "stock" one I have .... for the record I had no intentions of altering them, just curious bout the length rule..... thanks a bunch guys
 
sCREamnClones said:
Bryan / Don or, any 'tech'.......(similiar arena) except "S & I" doesn't apply becuz of 'Keyway' / Non-Tech status, However....If I 'machine' a relief in my Coil mtg bolts that wud allow abt 5* of 'fine' tuning timing, would I be DQ'd....becuz I 'machined'...filed or otherwise, a bolt? (it's a 'convenience' issue....Not Performace related!)
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Although There is no ruling that states you are allowed to do what you described, it is not a performance gain by any means. With that being said, I would inform you that what you did was not allowed by written rules and tell you to not bring it back the next time. If I see it again, I will call it.
 
conehead said:
the reason I asked the question was I see differences in the lengths of the ones in the carbs I have ,,,,,, just gonna go with the shortest "stock" one I have .... for the record I had no intentions of altering them, just curious bout the length rule..... thanks a bunch guys
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I do a section on the screw in my DVD. You are not allowed to modify it in any way. However, there are some of the screws that come in the Hayuai ( spelling ) carb that penetrate through the shaft very minimal. They also have the end of the screw peened (spelling) to sorta speak, that will make a less knowledgeable tech suspect that there was something done when in reality it was done that way from the factory. As long as the screw is visibly penetrating through the shaft, the head of the screw has not been tampered with and the washer is present, it is legal. Now, on a further note. I have dynoed and flowed the screws that are short vrs. the long ones and there is no noticeable difference between them. The little extra length does not disrupt flow enough to show a loss in performance.
 
conehead said:
the reason I asked the question was I see differences in the lengths of the ones in the carbs I have ,,,,,, just gonna go with the shortest "stock" one I have .... for the record I had no intentions of altering them, just curious bout the length rule..... thanks a bunch guys
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I used to spend time on the flowbench when working with the carbs on the flatheads and looking for the best butterfly screw set up for the carbs.

Many days I would get out and ride around to all the diffrent small engine shops and shade tree small engine shops to check out their inventory on these very type of things. They caught on very shortly after I started bringing my dial calipers to check length. They knew I was looking for specific stuff. For some reason the prices went up at a few spots. LOL
 
DynoDon said:
... As long as the screw is visibly penetrating through the shaft,...
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Is this in the rule book? When you say 'through the shaft', does that mean it has to come out the other side? I need to get a rule book? Where will they be available?
 
The way i read it, he said penetrating through the shaft, which means the screw has to go in one side and come out the other, meaning you cant have a screw that sits flush with the throttle shaft or you will get a DQ. That about right Don?
 
Weddle Racing said:
The way i read it, he said penetrating through the shaft, which means the screw has to go in one side and come out the other, meaning you cant have a screw that sits flush with the throttle shaft or you will get a DQ. That about right Don?
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Z....it's Saturday, ur up way 2-early! RU rac'n 2-day? :)
 
Weddle Racing said:
The way i read it, he said penetrating through the shaft, which means the screw has to go in one side and come out the other, meaning you cant have a screw that sits flush with the throttle shaft or you will get a DQ. That about right Don?
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That is correct
 
mike00b said:
Is this in the rule book? When you say 'through the shaft', does that mean it has to come out the other side? I need to get a rule book? Where will they be available?
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It is covered in the rule book under "compared to know stock part" As for the books, I am waiting to see if they were distributed in the tech at Charlotte. It was my understanding that they would be available for that show. As soon as I find out there will be a post made.
 
DynoDon said:
It is covered in the rule book under "compared to know stock part" As for the books, I am waiting to see if they were distributed in the tech at Charlotte. It was my understanding that they would be available for that show. As soon as I find out there will be a post made.
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I got a 2014 rule book at Charlotte. So lets get a good definition on the screw.
 
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