Production/ overbore?

[Carl Johansson]

so does this rule

7.J.1            Production: Production engines must be the same model as the model of the frame being used and must have STOCK EXTERNAL APPEARANCE. Production motorcycles must use OEM cylinders, heads and crankcases to comply with this class. OEM engine displacement determines the displacement class for competition. Displacement may not be increased beyond that class limit.  Starting mechanism must be retained and operable. Carburetors or throttle bodies must be OEM for that model production engine.  All production engines run in gas class. See Section 7.D.3

 exclude a bike in production class from the 0.02 overbore rule?

what about other bike classes?  does the overbore rule remain in effect?

I'm assuming this clears it up
7.B.13  Engine size:  Displacement must be greater than the maximum allowable for the next lower class.  To permit minor reconditioning of worn cylinder blocks, in classes other than Production, it is permitted to increase cylinder bore diameter .020 inch (.508mm) beyond that which provides maximum displacement for the class.  In all cases, the resulting displacement must be exceeded to qualify for the next higher class.  The .020 inch (.508mm) will be discounted for record certification and will be noted on the certification card and in the logbook."  2006 rulebook, page 95.

BTW -  what does "discounted for record certification mean?  will you still hold the record?  will they knock off a few MPH?  what does it all mean?


Carl "this could be a problem" Johansson

[JackD]

The stupidity that brought you the overbore allowance for selected bikes is not allowed in production for what equally good reason ?
Does it make you curious as to why and for who it is allowed ?
If it is not allowed in any car class ,  including if a bike motor is used , could that reason be invalid ?
Many reasons have been given for the elimination of that rule but they have all fallen on deaf ears it seems.

[aswracing]

You can overbore in production all you want, so long as you don't exceed the class size. For example, I know someone who overbored an 883 Sportster to 997cc and set a Production class record.

In classes other than production, you can exceed the class displacement by .020 of bore size. At least that's the way I understand it, and the way it's been applied when I've done it.

For example, my 1650cc bike is a 4.000 bore by 4.000 stroke, 2 cylinder (that's not an original HD size). That works out to 1647.4cc. However, at 4.020 bore, it's 1663.9cc. But it's still legal in the 1650cc class.

For that matter, I believe I could take it all the way to 4.023 bore, because with a 4.003 bore it's still under 1650cc.

[JackD]

That is correct in that production is not allowed to exceed the class upper or lower limit in total size no matter how you do it.
It is not allowed in any car class at all for good reason.
Could it be their is something wrong with the bike rule ?

"Special deals for special people are really special."

[narider]

Could it be their is something wrong with the bike rule ?

I believe so Jack, you know... in comparrison to all the other bike rules being so perfect.
The ECTA even ommited this rule some years ago(and even though it effected me personally it still made alot of sense to me to drop it), but it has since been readopted.

"Special deals for special people are really special."

Exactly... even the ECTA readoption was done for one specific person.

My mom always told everyone I was special... appearantly not enough!
Todd

[narider]

ECTA does not allow the +.020" bore in Production classes either... unless it's a pre '1956(production date) in which case it then allows a +.050" bore in any of the vintage classes(including PRODUCTION Vintage)
Todd(wonder what Forest thinks of that?)

[Carl Johansson]

heres my point of view.  The bike I'm working on was only sold in the US for 2 years 85 and 86.  its a 350 cc watercooled 2 stroke.  turns out they get reworked alot -  including overbores.  So now if I want to run production I need to go find some sleeves somewhere hard to come by in production bore -  -  i'm at 0.02 overbore -  that puts me at 352 CC -    man what a gigantic advantage over someone with a 349cc engine!!!!

I'm not trying to cheat or screw over or gain advantage over anyone -  I just want to run the bike!

Carl "I'm too big?  again?   boy if only I had a nickle for every time I heard that!" Johansson

That is correct in that production is not allowed to exceed the class upper or lower limit in total size no matter how you do it.
It is not allowed in any car class at all for good reason.
Could it be their is something wrong with the bike rule ?

"Special deals for special people are really special."

[JackD]

Todd
It sounds like a lot of other mothers that are only trying to get you out of the house so that your intended can finish you up or off if that doesn't work.

Carl
LA sleeve can fix you up with a sleeve that might even be better material than you started with.
It might be a little tough to explain the oversize to a car guy, especially one that is using a bike motor in a car.
An American sport might be served better with American standard measurements like the cars get and done in inches.
If the class limit is 60 inches, you are OK until you are 61 inches.
The degree of precision is always improving but the rule should not change.
Selective application is the real killer.