Yeah.
since you're already getting the billet flywheel and removing the governor, you might as well do the billet rod too. it becomes a weak link at that point. if it lets go, it can go straight up and hit you in a very bad spot.
I've been debating this for quite some time and still haven't made up my mind. If I do this, where does it stop? I might as well get the flat top piston, stronger studs and bolts, push rods, you know, the works! I've seen all those videos that Tom made and I believe he stated that he hadn't seen any problems with the stock rod. I understand it is like an insurance policy when you strengthen things. On the same token, we occasionally use are kart and really have no place to go flat out other than a school parking lot. And there really isn't that much room. I'll need to strengthen the chassis with this new found power,(brakes, bearings, fittings and joints). The list goes on. It only has a 2.5hp briggs on it now and goes 18 mph.
YouTube - Karting after the snow melt
I just wonder what kind of damage people see in the AKRA box stock class where they race these clones pretty muck stock with the exception of removing the governor.
Section 8 – AKRA Box Stock Project
Class Structure
Participant ages are determined as of January 1st.
BOX STOCK SENIOR* Age 15 years & up – 375 lbs. – 87 Octane Gas Only – Approved engine: BS Project 6.5
OHV only, with Factory Stock exhaust required. Stamped steel drum shoe type clutches only. (Tires EL Maxxis or
Local Club Tire Rule)
BOX STOCK SR CHAMP* Age 15 years & up – 400 lbs. – 87 Octane Gas Only - Approved engine: BS Project
6.5 OHV only, with Factory Stock exhaust required. Stamped steel drum shoe type clutches only. (Tires EL Maxxis
or Local Club Tire Rule)
BOX STOCK JUNIOR 1* Age 8 to 10 years – 265 lbs. – 87 Octane Gas Only - Approved engine: BS Project 6.5
OHV only, with .500 inch maximum intake restrictor, no steering fairing allowed , maximum nose height 14 inches
from ground level to top of nose, and Factory Stock exhaust required. Stamped steel drum shoe type clutches only.
(Tires EL Maxxis or Local Club Tire Rule)
BOX STOCK JUNIOR 11* Age 10 to 12 years – 290 lbs. – 87 Octane Gas Only - Approved engine: BS Project
6.5 OHV only, with .550 inch maximum intake restrictor, no steering fairing allowed , maximum nose height 14
inches from ground level to top of nose, and Factory Stock exhaust required. Stamped steel drum shoe type clutches
only. (Tires EL Maxxis or Local Club Tire Rule)
BOX STOCK JUNIOR 111* Age 12 to 15 years –320 lbs. – 87 Octane Gas Only - Approved engine: BS Project
6.5 OHV only, and Factory Stock exhaust required. Stamped steel drum
shoe type clutches only. (Tires EL Maxxis or Local Club Tire Rule)
ENGINE SPECIFIC TECH SHEET FOR: BOX STOCK PROJECT 6.5 OVH
Description: Single cylinder, 2 valve, OHV 4 cycle
Important Note: All parts must be Box Stock Project 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. There will also be a $200 claiming rule in place
for this engine. Refusing to accept the claimer will result in immediate disqualification of competitor along
with forfeiture of any points earned to date in class. Competitor will also not be allowed to compete any
longer in that class.
Combustion chamber volume: 27.5 cubic centimeter minimum, with piston at TDC, using prescribed procedure.
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. Stock exhaust
system only with no modifications. Any stock configuration gasket allowed no other sealer.
Bore and Stroke: Stock cylinder bore is 2.685” max. Stroke is 2.123” + / - .005”.
Carburetor requirements: Huayi 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. Main fuel jet .028” NO-GO. Stock air cleaner assembly only.
Valve Train: Stock valve cover only with any stock configuration gasket, no sealer.
Factory stock rocker arms and
push rods only. Stock valves only 45 degree angle only both valves, no modifications allowed. Only 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”.
Ignition system: Stock Box Stock system only and must be unaltered. Kill switch and low oil sensor may be
disabled and removed.
Flywheel: Box Stock flywheel only with plastic fins. No alterations of any type allowed. Must also run stock
flywheel key.
Piston and Rings: Must be unaltered Box Stock only. No machining of piston and rings allowed.
Connecting Rod: Stock Box Stock rod only. No machining of any type allowed. Stock rod bolts only.
Crankshaft Requirements: Stock Box Stock 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.
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 modification.
but I want to clean up the bulky air cleaner box and the exhaust.
