What you need to go Box Stock (Clone) Racing

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What you need to go Box Stock (Clone) Racing

Post  Admin on Sun Jan 03, 2010 2:41 pm

The Box Stock (Clone) class requires very little maintenance and is very inexpensive to race, a competitive ready
to race kart can be assembled for $600-$1000 very easy with a used chassis.
It’s a perfect class for new and old racers on a budget or that just want to
race without the higher cost associated with most 2 cycle classes. There are
several motors that are legal, the most popular is the Harbor Freight 6.5hp OHV
motor that can be purchased as low as $99.99 with a discount coupon.

We use 87 octane pump gas and most of us use old tires, you must use 4.50 tires on the front and 6.00 on the rear.
We race with the AKRA rules with a few modifications for sprint racing. There is a $200 claimer rule
on the motor & carburetor only. No internal modifications to the motor or carburetor
are allowed other then removing the governor, jetting and adding a pulse pipe for the fuel pump. The fuel tank must be
removed from the engine and will be replaced with
a remote floor-pan mounted fuel tank and a pulse-style fuel pump.
pump may be pulsed from either the crankcase, or the rocker cover

See rules for further details.

There are a number of online dealers you can buy parts from, however you can get
everything you need from ARC Racing except the motor mount. Tom Cole is great
guy to deal and an innovator of the Box Stock class. ARC Racing sells a kit that has 80% of
everything you will need for the motor, the other parts are listed below in the
links. Most of us use a 15t driver for the clutch for most sprint tracks, total prep time for
the motor is usually about 30 minutes the first time you do it. Please see the link below for
removing the governor.

You will also need #35 chain and split sprockets, most of the local kart shops sell
them. Mount the sprocket carrier inside the bearing carriers, be sure the kart
you purchase has a keyway for this or you will need to buy a new axle. We have
found that the BMI motor mount works on every American and European kart we have put them on
since it's adjustable side to side as well as back and forth.

Here are some useful links for parts and information you will need;

Video of Box Stock class at Dixon

Video on how to remove the governor.

BMI 15 Degree Motor Mount
Part # 600620
SKU Number:600620

Price: $38.95


ARC Racing Parts

Max Torque Shoe style centrifugal drum clutch for the Box Stock class. (15t recommended)
Price: $52.00

Box Stock Parts Kit

Price: $124.99 $114.95

You will also need a few jets, #36 - #40 should get you started.

That should do it! If you have any questions, just ask, the Box Stock racers a friendly helpful group. Please feel free to add to this list.

2010 Rules

2010 Box Stock Rules

List of Approved Engines
Any 6.5hp Honda Clone
MODEL: 6.5hp 196cc OHV Engine (168 Series)

Also rebadged and sold under (but not limited to) the following names;

BS (Box Stock)
Central Machinery
Northern Tools
Carroll Stream Motors
Blue Max

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 $150
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:
26.5 cubic centimeter minimum, with piston at TDC.

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:
OR RUI*ING 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. Venturi .615” NO-GO. Rear carb bore
.751” NO-GO. Main fuel jet .042” NO-GO.

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 .0705” 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.

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, must meet the following specs;
Cam lobe base circle diameter .865" -.005”/+.010”
check for Intake and Exhaust lobes (taken off pushrod). 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.)

Max Intake lift on cam .225” taken at the pushrod.
Max Intake lift at the valve .238” Taken on valve spring retainer with zero lash.
Max Exhaust lift on cam .232” taken at the pushrod.
Max Exhaust Lift at the valve .242” Taken on valve spring retainer with zero lash.
Special note. Valve guide wear can give false valve lift readings when checking
off the front of the valve spring retainer. It is advised to take
readings at several other points around the retainer (back, and both
sides) if wear is suspected of giving a false, unfavorable reading.

Block Requirements:
must remain stock as produced. Stub for governor may be removed and the
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:
Mounted fuel tank mandatory (stock tank must 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). Main fuel jet may be drilled to a no-go of .042 inch. Stock
emulsion tube must be used and unaltered.

Header and Muffler Requirements:

Any single stage, one piece header made from .750” O.D. steel tubing allowed with the BS
style muffler part # 89966 or it’s aftermarket equivalent (ex: rotary
power) installed at the end of pipe. The tube style muffler may either
be welded or tread fitted to the pipe end. The entire exhaust pipe
including the muffler is 14” max length and 10” min length.

Claimer Rule:

must be entered and race in the box stock class to claim an engine for
$150 (minus the clutch/chain guard/throttle kit, header pipe/muffler,
air filter adapter/air filter, top plate & fuel pump).

Box Stock addition to the “Claimer Rule” above.

must state intention to claim, to track officials with money in hand
within 10 minutes of end of the race. If the "claimed engine" fails
tech, or if any engine that is used on competition day, fails tech due
to cheating, the owner and/or of said engine will be
suspended from
participating in the next race. A second technical violation in the
same season will result in non-participation for the remainder of the
races and loss of all
points. An engine claimer waiver is to be
signed at each event by all box stock class participants. The
participant agrees to become familiar with and abide by all rules,
specifications and procedures as set forth in this rulebook and
prescribed subsequently by the Gold Rush, its affiliates, officers or
designated representatives. Please see claiming wavier for more details.

Gold Rush Box Stock rule modifications;

1) If it does not state that you can, then it is not legal to do it.

2) Box Stock tire rules are used Bridgestone YKC. 4.5 x 5”
fronts tires and 6.0 x 5” rear tires. Tire doping applied on or in the
tires, at or off premises is prohibited.

3) After market carburetors, modified carburetors and Blueprinted carburetors are prohibited.

4) 87 octane unleaded, oxygenated, California refinery blended fuel w/ no
additives. (This is not race fuel it is California spec. pump gas)

5) Senior Clone class 16 years old and up weight is 360 lbs.

6) IKF chassis and driver preparation rules will be enforced.

Last edited by Admin on Wed Aug 04, 2010 2:50 pm; edited 3 times in total


Posts : 46
Join date : 2008-06-04


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Post  Admin on Wed Jul 28, 2010 2:24 pm


This form must be signed at time of entry by all Box Stock Competitors

Box Stock Claim Rules:

will be only from competitors in the same race group that may make a claim on
an engine.

may be claimed for $150.00 cash only. The claimer may state their intention to
claim an engine at the scale to hold the claimed engine in impound. No claim
related inspection will be started prior to the funds being posted with the
proper official.

claim form and cash must be submitted to the Race Director or Tech Director or
his or her designee, no later than 10 minutes after the end of the main event
race that the claimed engine is participating in. I.E. End of race = Checkered
flag lap complete and all karts are at the scale house.

Race Director, or his or her designee, will hold the claim money until the
claimed engine has been inspection for legality.

claimed engine will be tagged/marked and sealed as soon as it comes across the
scale after a claim has been submitted.
Areas to be sealed are valve cover to head, head to cylinder, block
cover to block, carburetor to manifold and muffler to header.

claimed engine will be immediately taken to impound and/or presented to the
tech director for inspection following the main event for Box Stock in which
the motor was claimed. Engine must remain in impound and in the possession of
tech officials until tech inspection has been performed.

claimer and claimed have the option to be present at the time of inspection.

claim that is withdrawn will be assessed a $50.00 fee that will be paid to the
Host Club

claims on an engine will be decided via a lottery system. Owner, Driver or
family member cannot claim his or her own engine.

party will retain engine mount, air filter & cup, fuel pump, exhaust
system, clutch, chain guard, top plate and throttle linkage.

If the claimed engine is found to be illegal, the motor must be completely torn
down to check for additional illegalities. The Tech Director must confiscate
ALL illegal parts and related parts from the claimed engine.

of claim, destroying or withholding of parts, or any other lack of cooperation
in this claim or inspection process will be interpreted as an admission that
the engine is illegal and will be subject to an immediate disqualification and
loss of all points for the day. Driver
may also be subject to the conditions set forth in the Box Stock club or local

By signing this waiver, you acknowledge
that you have read and understand the claiming procedure for the Box Stock
class and agree to its terms and conditions. If driver is under the age of 18
years old, a parent or legal guardian must also sign the wavier.

Driver Name (please Print)_______________________________________________


Parent or Legal Guardian of
minor_________________________________________ Date___________


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Post  Admin on Wed Jul 28, 2010 2:27 pm


Claim Price $150.00 Cash to be submitted with claim form


DATE: ________
Time of Day:___________ A.M/P.M. Location
of event: __________________________________

Name of driver making
claim _________________________________________ Phone #________________________

Club_____________________________________ Kart#___________

Driver name of
claimed engine________________________________________

Phone #________________________

Home Club

Also provide
information of engine owner if different from above

__________________________________________Tech Staff Only__________________________________________


Name of technical official
inspecting engine __________________________________ Phone # ____________________

Engine ID#_______________________

Choose below:

The above engine
has been inspected by me, (
Signature _____________________________), and has been

found to be LEGAL at this time.OR The above engine
has been inspected by me, (
Signature _____________________________), and has been
found to be ILLEGALfor the following
reasons: __________________________________________________


Person responsible for retaining claim funds until the results of the final inspections are determined.

Name ___________________________
Phone #________________


party will retain engine mount, air filter & cup, fuel pump, exhaust
system, clutch, chain guard, top plate and throttle linkage.


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