Lightning valley ohv blue motor rules for 2008
Box stock class

1. 6.5 OHV Central machinery or jiang dong engine only
2. all parts may be checked against a known stock part
3. absolutely no honda parts
4. must have stock flywheel & key
5. flywheel timing must be in stock position. Check with timing light.
6. stock cylinder bore is 2.685 max
7. stock stroke is 2.123 +/- .005
8. combustion chamber volume with piston at tdc to be 27.5 cubic centimeters minimum
9. ignition system must be stock and unaltered. Kill switch and low oil sensor may be disabled and removed
10. stock air box. Central machinery or jiang dong. Stock carb. Central machinery or jiang dong. Carb: a. throttle shaft .118 b. throttle valve minimum .037. c. throttle valve bore max .751. d. venturi .655 e. jet minimum .026. f. jet maximum .030. g. stock filter and foam outer.
11. head gasket minimum .008. no copper or aluminum gasket.
12. piston od 2.677. piston depth dish minimum .040. stock piston rings only. Stock rod only.
13. head depth between valve .240. a. head will be cc’d for combustion size. B. valve seats 45 degrees. C. valve seat maximum diameter: intake .897; exhaust .857.
14. valves +/- .005. intake valve .985; exhaust valve .945
15. valves minimum margin .035.
16. valve spring pressure maximum 10.8 at height of .850. no valve spring shims.
17. no porting of head
18. stock cam maximum lift .245. zero valve lash directly off valve retainer. Stock timing on camshaft.
19. piston must me .004 or more below top of deck
20. header. Maximum length 14 inches. .750 maximum id. No step in header. Flat washer weld on tip only.
21. pump gas only. No additive of any sort allowed. Tech with digitron meter.
22. stamped steel drum shoe type clutches only.

These rules apply to all stock ohv engine racers. We will retain the $150.00 purchase engine rule. Racer must finish on the lead lap of the race. You cannot purchase an engine that is not in the race you are running. We reserve the right to inspect any engine at any time.