ENGINE SPECIFICATION TECH SHEET FOR KLONE CLASS ENGINES
Description: Single cylinder, 2 valve, OHV 4 cycle
The new harbor freight BLACK motors are not allowed and are illegal.
Important Note: All parts must be Box Stock factory production parts unless otherwise
specified in this rules manual. No machining or alteration of parts is allowed unless
specifically noted. All parts will be subject to a comparison to a know Box Stock part (when
performing a comparison check it is recommended to use a + /- .005” tolerance). Engine will
be teched as raced.
Combustion Chamber Volume: 27.5 cubic centimeter minimum, with piston at TDC, using
Cylinder Head Requirements: Must be OEM casting only. Porting and / or grinding are not
permitted. Valve seats are two angles 45 degrees valve face and 30 degrees top relief.
Stock head bolts only, must have four. Head gasket maybe after market, must be of stock
configuration. No copper or aluminum gaskets allowed. Multiple gaskets allowed to meet
minimum CC rule.
Head gasket surface on block and head may be machined to true surface.
Stock exhaust gasket. No other sealer is allowed.
Bore and Stroke: cylinder bore is 2.7155” max to allow compensation for +.75mm dished piston for rebuilds in 2012. Stroke is 2.123” + / - .005”.
Carburetor requirements: Huayi or Ru-Ying model carb only.
Carb to intake sealer is gasket only. No other sealer allowed.
Choke must be as supplied from factory, but may be fixed to stay in open position.
Choke bore .810” NO-GO.
Venturi .615” NO-GO.
Rear carb bore .751” NO-GO.
Low air/fuel jet .028” NO-GO
Main fuel jet may be drilled to a no-go of .042 inch.
Stock emulsion tube must be used and unaltered.
Valve Train: Stock valve cover only with any stock configuration gasket, no sealer.
Factory stock rocker arms and push rods only.
Stock valves only. A 45 degree angle only for both valves, no modifications allowed.
Box Stock valve springs only.
Max wire diameter on spring wire is .698” with a maximum tension of 10.8 lbs. at a height of
.850”. Valve springs may be teched at any time during race event.
Ignition system: Stock Box Stock system only and must be unaltered.
Kill switch and low oil sensor may be disabled and removed.
Box Stock flywheel only with plastic fins. No alterations of any type allowed.
Must also run stock flywheel key.
****FOR 2012 YOU HAVE THE OPTION TO RUN A ARC Billet (part number 6619) or any steel flywheel that is of stock weight and size.
****Timing can be changed up to a max of 18 Degrees and will be measured by the procedure outlined on the ARC website videos.
*****Stock pull rope must still be used, no electric starters.
***Taping of shroud may be allowed
Piston and Rings: Must be unaltered Box Stock only. No machining of piston allowed.
Piston cannot exceed the deck height. No pop-up is allowed.
For 2010 competition year a dished .25mm (.010”) piston may be used.
A .50mm dished piston will be allowed in 2011, and .75mm in 2012 to allow engines to be used
for multiple seasons. The appropriate oversize rings of stock appearance are allowed.
Connecting Rod: Stock Box Stock rod only.
Rod may be honed for clearance of crankpin and wrist pin only.
No additional machining of any type allowed.
Stock rod bolts only.
Crankshaft Requirements: Stock OEM crankshaft required.
Machining, polishing, addition of material or other alteration of crankshaft is prohibited.
Stock factory timing gear mandatory and must be installed in original location.
Crankshaft journal diameter is 1.180”- 1.175” min.
Camshaft Requirements: Stock as cast camshaft only. Maximum running lift of .245”
checked at valve as run. Dyno CL-1 Camshaft allowed as long as it meets spec.
Camshaft Requirements: - Duration check for Intake and Exhaust lobes.
Intake duration of 218.5 degrees at .050 lift/85.5 degrees at .200 lift.
Exhaust duration of 221.5 degrees at .050 lift/96.5 degrees at .200 lift.
(All checks will allow +2 degrees for wear and gauge variances.)
These are the specs on the CL-1 cam
0.22386" --- PEAK LIFT
0.23083" --- PEAK LIFT
The base circle also measures in spec.
Block Requirements: Block must remain stock as produced.
Stub for governor may be removed and hole plugged.
No machining of block allowed.
Welding to the block shall be for rod damage repair only and may not constitute a functional
Carburetor/Fuel Tank Requirements: Floor Mounted fuel tank allowed (stock tank to be
removed). Pulse type fuel pump allowed. Fuel pump must be pulsed from either the crank
case or the valve cover. You may install a flat metal plate in the original tank location for
the purpose of mounting the throttle linkage and fuel pump.
Aftermarket air filter adapter allowed (max length of 1.375).
Header and Muffler Requirements: Header may be bent in any
configuration to keep it away from the driver and so the muffler will not extend past the
rear bumper. Otherwise non tech.
It is recommended that the header be securely wrapped from 2.0” past
head flange to swedge where muffler is mounted. Muffler cannot be wrapped. Muffler
must be stock as produced by RLV. Part number approved are part #4104,4100,and 4117. No paint or coatings.
Disclaimer: These rules may be modified as necessary by the Vice President of Competition
to keep the engines within the original intended intent of the class, which is to provide fun,
affordable, entry level racing to MEMBERS of the Mid-State Kart Club and other
enthusiasts who wish to participate at Mid-State Kart Club sanctioned races.