I have been checking on the legality of running bored engines like Eric Gorr , Max-Power and RPM build. I questioned the AMA on using a 310 kawasaki built by Eric Gorr in the open class in the AMA Hare Scrambles Series. I was told that these engines are illegal for cross country competition because they were bored and replated instead of sleeved with a liner.
This is the answer I got from the AMA......
I know this is going to sound stupid but these are the rules. You can overbore a cylinder .080 inches and still be legal to run in the same class. I am assuming that you have a 1992 or older model. That being the case then .080 over fro you would be 265.5cc. To move to the next displacement class the following applies.
From Chapter 3 , Section C. in the rule book:
The use of kits or sleeving is allowed in all forms of off-road competition in
the 200cc and above classes only. Kits must change the displacement a minimum
of 10% beyond the AMA recognized class limits and must have the correct
displacement stamped on the side of the cylinder
From Chapter 1 - Definitions:
KiT - An over the counter, available for sale to the general public,
assembly of parts designed to increase the
displacement of a motor a minimum of 10% beyond the AMA recognized class
displacement for the purpose of changing classes. A motor so modified must
have the correct displacement stamped on the side of the cylinder.
SLEEVE A cylinder insert.
By overboring only, what you have done is not legal in AMA competition. To
change your machine to the open class you will have to have a big bore kit
installed.
This has happened because the rule allowing kits and sleeving was added a few
years ago and the previous rule was still in place that prohibited riders from
modifying their machines to change classes. If you think this rule needs to be
changed then you must contact your AMA congress delegate. He can be located on
the AMA web site at AMADirectlink.com in the "AMA Sports" section
I checked the GNCC supplemental rules which have been approved by this office
and they read:
4. Open Classes (Motorcycle) - If a manufacturer
produces an open size machine(HON & KAW), no 250's
will be allowed to use Big Bore Kits. If a
manufacturer does not produce an open size
machine(YAM & SUZ), 250's will be allowed to use a
manufactured Big Bore kit. You cannot over-bore a 250
engine to run in the open class. Cylinders must be
stamped with new engine displacement
As you can see a 308 overbore is not allowed in
the GNCC series or other cross country type events.
If you have any other questions please contact us
again.
Sincerely,
Roger Ansel
AMA Sports Manager
This is the answer I got from the AMA......
I know this is going to sound stupid but these are the rules. You can overbore a cylinder .080 inches and still be legal to run in the same class. I am assuming that you have a 1992 or older model. That being the case then .080 over fro you would be 265.5cc. To move to the next displacement class the following applies.
From Chapter 3 , Section C. in the rule book:
The use of kits or sleeving is allowed in all forms of off-road competition in
the 200cc and above classes only. Kits must change the displacement a minimum
of 10% beyond the AMA recognized class limits and must have the correct
displacement stamped on the side of the cylinder
From Chapter 1 - Definitions:
KiT - An over the counter, available for sale to the general public,
assembly of parts designed to increase the
displacement of a motor a minimum of 10% beyond the AMA recognized class
displacement for the purpose of changing classes. A motor so modified must
have the correct displacement stamped on the side of the cylinder.
SLEEVE A cylinder insert.
By overboring only, what you have done is not legal in AMA competition. To
change your machine to the open class you will have to have a big bore kit
installed.
This has happened because the rule allowing kits and sleeving was added a few
years ago and the previous rule was still in place that prohibited riders from
modifying their machines to change classes. If you think this rule needs to be
changed then you must contact your AMA congress delegate. He can be located on
the AMA web site at AMADirectlink.com in the "AMA Sports" section
I checked the GNCC supplemental rules which have been approved by this office
and they read:
4. Open Classes (Motorcycle) - If a manufacturer
produces an open size machine(HON & KAW), no 250's
will be allowed to use Big Bore Kits. If a
manufacturer does not produce an open size
machine(YAM & SUZ), 250's will be allowed to use a
manufactured Big Bore kit. You cannot over-bore a 250
engine to run in the open class. Cylinders must be
stamped with new engine displacement
As you can see a 308 overbore is not allowed in
the GNCC series or other cross country type events.
If you have any other questions please contact us
again.
Sincerely,
Roger Ansel
AMA Sports Manager