PRO CLONE RULES
PRO CLONE HEAVY - 400 lbs min (driver must weigh 200 lbs)
Thursday, July 30, 2015
PRO CLONE RULES
These Rules Apply to All of our Clone Classes, Jr's. & Sr's.
PRO CLONE LITE - 325 lbs. min
PRO CLONE MEDIUM - 350 lbs. min
There will be a Professional Tech here
occasionaly so we strongly suggest all racers
come ready to race with a legal engine.
2014 AKRA pro clone engine rules apply
The only motors allowed in this class are Single
cylinder, 2 valve, 6.5 (196cc) Over Head
Valve (OHV) 4 cycles (CLONE ONLY) such as: the
Harbor Freight blue clone, the Grayhound, BaHa
TSC motor & the oringal box stock project.
Combustion Chamber: 26.5 (CC) cubic centimeter
minimum, with piston @ Top Dead Center (Tdc)
Cylinder Head Requirements: Must be oem casting
only. Porting & or grinding are not permitted. Valve
seats are two angles 45° valve face & 30° top relief.
Intake seat maximum Inside Diameter (ID) .897".
Exhaust seat maximum ID .862". Outside face of
valve may not be below floor of the combustion
chamber (Don't sink the valves.) Stock head bolts
only, must have four. Head gasket or gaskets are
allowed. Head gasket thickness is a NON-TECH item,
however the Depth Check between the valves from
front to back & side to side may not vary by more
than .005". Any stock configuration exhaust gasket
allowed (no sealer.) Max. Stroke is 2.123" + .010"
or - .005". Matting surface finish of block and
cylinder head is NON-TECH item, surfacing of both to
correct gasket failure & meet cc check allowed
however, no piston pop out is allowed. May use 2
stock side cover gaskets. Stub for govenor may be
removed and hole plugged. No machining of block
allowed except on top of cylinder to meet cc check.
Welding to the block shall be for rod damage
repair ONLY and may not constitute a functional
Carburetor Requirements: Huayi or Rui*ing model carbs
only. Carb to intake sealer is gasket only, no sealer
allowed. Choke must be intact as supplied from
factory, but may be fixed to stay in open position.
Venturi .615" No-Go. Rear carb bore. .751" No-Go.
Main fuel jet .042" No-Go. Low speed idle jet is a
NON-TECH item. Stock emulsion tube must be used
and unaltered, .066" max ID (no pass through.) Side
holes in E-Tube: 4 holes max in bottom section and
20 holes max in top section. Min. E-Tube length is
1.092". Throttle shaft - .115" minimum. Butterfly -
.027" Min. Aftermarket air filter adaptor allowed
(Max ength of 1.375".)
Air Filter: K&N style air filter allowed. Maximum
length is 4 inches long. No type of air catcher is
allowed. All air filters must be fastened using a
hose clamp. All prefilters must be strapped onto
air filter with either an elastic band or zip ties
depending on which type of prefilter you are
using note: if either one falls off once the race
has started. caution will come out and you will go to the back.
Valve Train: Stock valve cover only with any stock
config. gasket, no sealer. Factory stock rocker arms
1:1 ratio & push rods only. Stock valves with only a
45° angle on either valve. Intake valve Max OD
.982" +/- .005" & Exhaust valve Max OD .948" +/-
.005", no modifications allowed. (Installed height
for valve springs .815", must be checked by using the
.815" spring must go gauge with retainer seal in place
on intake and exhaust valve if used.) Prescribed
check procedure as follows - Remove valve spring,
reinstall spring retainer, insert .815" must go gauge
in spring location. Gauge must go in both locations
Intake & Exhaust with any allowed retainers in place,
as raced, during check procedure. Max wire
diameter on spring wire is .071" with a maximum
tension of 10.8 lbs. at a height of .850". Lash cap
on Exhaust valve only. Valve stem seal allowed on
Intake & Exhaust valve, maximum lip thickness of
.027". Minimum thickness of Intake retainer .230",
Exhaust retainer .250". Box stock lifters only, no
Ignition System: Kill switch and low oil sensor may be
disabled and removed. Must use stock ignition
module. A flat washer or spacer maybe ran between
the flywheel & the nut. 2013 AKRA RULES APPLY
Piston & Rings: Must be unaltered Box Stock only. No
machining of piston and or rings allowed.
Connecting Rod: Must be unaltered Box Stock rod or
billet rod of stock length if desired. No machining
of any type allowed. Must also run stock rod bolts
Crankshaft Requirements: Must be unaltered Box Stock
crankshaft. Machining, polishing, addition of
material or other alteration of crankshaft is strictly
prohibited. Stock factory timing gear mandatory and
be installed in original location. Crankshaft journal
diameter is 1.180" Max - 1.168" Min.
Camshaft Requirements: Must run Box stock cam or
CL-1 cam if desired. Duration check for Intake &
Exhaust lobes (taken off pushrod.)
• Intake duartion of 219° @ .50 lift/86° @ .200 lift.
Exhaust duartion of 222° @ .50 lift/97° @ .200 lift.
• Max Intake lift on cam .225" - Min .215" lift taken
at the push rod. Max Intake lift at the valve .238"
taken on valve spring retainer with zero lash.
• Max Exhaust lift on cam .232" - Min .222" lift taken
at the push rod. Max Exhaust lift at the valve .242"
taken on valve spring retainer with zero lash.
(To achieve zero valve lash for checking running left,
preload dial indicator by .001")
Blower Housing Assembly: Pull starter may or maynot
be used. If used pull starter may be rotated for a
better crank angle. If an electric starter is going to
be used the pull starter may be removed however a
flywheel screen MUST be added.
Header & Muffler: Any header staged or non staged
may be used with the exception of no looped
headers. RLV small whole muffler must be
attached to the header, with all baffles in place.
Muffler must be supported by
a clamped on brace, safety wired from the
exhaust end or welded together (if welded
together be prepaired for it to be cut off by Tech
if they need to.) Header & muffler must stay
atleast 1/2" inside all body and bumper lines.
Header wrap must be used and securely
fastened in place and wrapped from the exhaust
flange to the muffler in JR. CLASSES only prior
to entering the track. Adult classes may wrap
header if desired. (This is strictly for safety to
protect our lil guys & gals, not to single anyone
Fuel Tank Requirements: Floor mounted fuel tanks
are mandatory, stock tank must be removed (This
is another safety issue to prevent gas leakage on
exhaust and ignition & prevent the chance of fires
on a roll over situation.) Pulse type fuel pump
Fuel Pump Requirements: Fuel pump must be pulsed
from either the crank case or the valve cover. You
may install a top plate in the original tank location
for the purpose of mounting the throttle linkage &
Fuel Requirements: You must run pump gas only with
no additives, 87 octanes ONLY There could be an
electornic fuel tester or syringe style used to test
fuel on any given night.
Clutches: Stamped steel drum shoe type clutch or disc
clutch maybe ran in these classes. If you choose to
run a disc clutch, you may run upto a 2 disc. No 3
disc or higher clutches allowed in clone classes.
Tire Requirements: You must run BURRIS tires. Any
compound of burris tire is acceptable as long as they
are slicks. No treaded tires will be allowed, this
includes any grooving notching etc.
NO CLAIM RULE ",,
Don't Forget to check our our Track
Specific Rules under Track Rules at the
top of the page.