Quick Jump: Engines - Engine Kits - Heads - Blocks - Carbs

Jimmy Rivers is the author of the “Speed Shop Scholar”, a tech series featured monthly in “Chasen Racen Illustrated”, Dirt Karting’s premier publication. Covering a wide variety of topics to assist the racer.

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Online Specials

• Signature Series Pro Clone Engine Package $1,150
• Free Commercial Shipping on Recon Chassis C/E & Elite
• Free Powder Coat with any new JRPW Engine Package


2018 JRPW Signature Series Pro Clone Engine Package

This is the ultimate in stock class clone engine Horsepower. JRPW has made the investment in research, development, and machinery to insure the highest level of performance.  JRPW uses its state of the art machine shop to precisely machine and massage the hand selected internals to the razor’s edge. The JRPW  “Attack Series” cylinder head and carb package tops it off. Here at JRPW, we believe in walking all over the line set by the technical regulations, but not across it. Every engine is painstakingly assembled, checked, and double checked to verify every aspect is perfect, then we test and tune on the dyno to quality control. This package is complete with all linkages, sleeved header/ muffler assembly, chain guard, all hardware. We only offer this top level package, nothing else is acceptable. The blower housing and recoil is custom powder coated in your choice of color, standard. JRPW engines set the bar in performance as well as appearance.


2018 JRPW Signature Series Pro Open F92

This is the Big Brother of our Pro Open engine above. Same internals and parts, except the block is machined and sleeved to accept a 3” piston. The Honda block is standard equipment here. There is no substitute for cubic inches, and we take full advantage. Feel the earth move as you wrestle with this beast.


2018 JRPW Signature Series Pro Open OHV

Beginning with the clone engine, we completely gut the case and precision overbore the cylinder WAY oversize. The case is machined to accept all the high performance internals we use. We also take the time to brace the block for additional support. The head is fully modified with 32mm and 28mm stainless valves and topped with dual valve springs and hp retainers. Compression ratio is calculated and parts are machined to optimize performance. Roller shaft rockers finish the head assembly. Billet crankshaft, billet rod, forged piston, billet crankcase cover, and a billet flywheel are all standard equipment. The package is completed with a blueprinted Mikuni carb, as well as the header/ muffler assembly. This one is definitely not for the faint at heart, as this engine makes in excess of 31 hp. Practice your grip, you will need it to keep this monster under control. An upgrade to a Honda block is an additional $100


JRPW 212 Level 1

Ducar 212 Engine, complete with PVL indestructible flywheel. The governor assembly is removed and all internals inspected. We add a ground camshaft and appropriate valve springs, top it off top plate, fuel pump, and inline filter. Carb is properly jetted and filter adapter and air filter installed. Complete with chain guard, this engine is ready for a mini bike or kart with the addition of exhaust system which is available at additional charge. This engine makes approximately 14.5 hp depending upon header choice.


JRPW 212 Level 5

Ducar 212 Engine as above, but with added billet connecting rod, upgraded camshaft, advanced timing, and a cut cylinder head. This engine will make an additional 2-2.5 hp over above package.


JRPW Level 5 Modified

For the Modified racer wanting a lot of HP at a lower cost, this is a package that makes the power and is upgradable to make even more power. Included is a big bore, long rod rotating assembly with a stock stroke. We top it off with a ported and machined cylinder head assembly including stainless valves, HD retainers, dual springs, and an aftermarket rocker assembly. We feed the air to this package with one of our 690 Attack Series Alky Carbs, with a Mikuni upgrade for an additional $149.95. This is a race ready package, pick a color, and bolt it on.


JRPW Limited Modified Flathead

Regaining popularity due to several high profile money races across the Southeast, this is the current version of the original workhorse. Best of everything, machined and caressed like only JRPW can, this one is ready to take the winner’s purse anywhere you want to take it. Complete just like all our packages, ready to bolt on and go.



Briggs LO 206 Engine, maximized and tweaked to the edge of legality. JRPW performs a perfect valve job on our Rottler seat and guide machine, and takes all other components to the limits. The engine is dyno tuned to extract every possible bit of power. Package includes spec header/ muffler assembly, chain guard, and spec air filter.


JRPW Mini Mod

For the budget racer wanting a reliable engine package that packs a big punch, here you go. We upgrade the cam and valve springs, add a billet rod and flat top piston, and assemble it all to our precision standards. The head is machined, and we add one of our 650 Attack Series carbs. Billet flywheel, header assembly, chain guard, its all there and ready to race. Pick your fuel, alky or gas, and pick your color, we will handle the rest.


JRPW Predator Blueprinted Stock

Hemi or standard predator engine blueprinted to stock class rules. JRPW has the ability to work between the lines to boost power levels significantly over out of the box. Includes top plate, fuel pump, header/ muffler assembly, and chain guard. Dyno tuned to maximum performance.


JRPW Pro Open Animal

For the Racers wanting the power and Speed of a JRPW Open but using the Briggs Animal engine as a base, this is for you. The best of everything is here, Mikuni carb, billet components, and expert craftsmanship are front and center, and the result is nothing short of incredible. Bored, stroked, and machined the JRPW way.  It’s ready to add liquids and a clutch, the rest is included. Upgrading to a billet head is an additional $300


Signature Series Animal Engine

This is the Briggs and Stratton Overhead valve racing engine. Fully blueprinted, ready to perform. We use our years of experience and expertise, coupled with our machining capability to transform this engine from ordinary to extraordinary. Standard procedure here at JRPW is to sort and hand select each piece we use, it is the only way we can achieve the results we both desire. To the limits, thats the way we do it every day. Each engine includes all throttle linkages, sleeved header/ muffler assembly and chain guard. Choose your color, and hold on, we are ready.


JRPW SSA Stock Appearing

JRPW has a supply of these special small block, 3” bore engines. Prepared in the JRPW way, these engines have a special “Attack Series” Level 10 head, “Attack Series” 390 Max carb, roller rockers, HD pushrods, special cam grind, and all the bolt-ons necessary to make it race ready. Hands down, the most powerful stock appearing for the price anywhere. Choose a color, and give us a call. Further upgrades are possible, contact us for details and pricing.


Signature Series Dual Bearing Flathead

Our quality machine work, testing, and experience set this engine apart from the competition. This engine is fully machined, with replacement valve seats and full length valve guides precision honed to size. We weld the lifter bore, angle deck the cylinder, and port and polish for max airflow. We align bore the cylinder and finish hone to exacting clearance. The valve seats are perfectly finished with our Rottler seat and guide machine. We add a pair of blueprinted valves, a pair of perfectly matched valve springs, and top off the cylinder with one of our machined heads. We complete the package by adding one of our signature “Attack Series Carbs”, with its precision machined body, offset throttle shaft, and hand picked internal parts to insure the highest possible airflow. Included in this are a pair of billet lifters, billet rod, and all the go fast goodies we can legally fit inside this powerhouse.  Each piece is hand selected to insure maximum horsepower. This engine comes standard with our billet header support, oil vent kit, and a lightweight filter adapter. Restricted class engines also include a max-size restrictor plate. Dyno tested and tuned to meet our highest standards of quality, this engine is ready to bolt on and win,,,,,,, just add oil and fuel. Powder coating is also included at no additional charge.


Signature Series Stock Appearing

This engine uses the same internals and machine work as our Signature Series Open Modified, just in a stock appearing format. The best of the best, its all there. Topped off with one of our killer 690 Attack Series Carbs, or, if allowed, a prepared and bored 390 carb. As with all JRPW packages, it comes complete, powder coated, and ready to race, including all bolt ons and accessories.




New 420cc Clone Engines. Electric and recoil start. Top quality. 90mm bore x 66mm stroke. 1” output shaft perfect base engine for motorsports or as a replacement engine for power equipment. Brand new exhaust port design offers increased torque over previous designs. $369
New 414cc Clone Engines. Recoil start. 90mm bore x 65mm stroke. Same quality, specs, and details as the 420, with a slightly shorter stroke. $335






Engine Kits

Animal Stroker Kit

This includes an ARC billet crank, ARC billet rod, Wiseco piston, HD wrist pin, correct timing gear, pto bearing, and pto oil seal. Bore sizes from 2.702 and up. 2.756 is often the largest bore the stock sleeve will accommodate.


Clone Stroker Kit

Includes ARC billet crank, ARC billet rod, Wiseco piston assembly, and HD wrist pin. Available in bore sizes from 2.682 to 2.815


JRPW 28MM Mikuni Kit

Mikuni carbs prepared by JRPW have been taking the modified community by storm for several years. The JRPW blueprint along with the ease of use and the partial throttle response that makes it easy to be gentle with the power, has made this  a top choice in the modified classes. Clone or Animal, this package is complete with blueprinted carb, intake manifold, filter adapter, and all linkages. Alky or gas, its ready to use.


JRPW Pro Clone Kit

For the racer that wants the JRPW touch, with the option to assemble the engine on their own, this is the kit for you. This kit will provide the racer access to the precision machine work and parts selection that has made JRPW one of the premier shops in karting. Complete with our trademark “Attack Series” cylinder heads and carbs, header, muffler, etc, these kits include every bolt, bracket, clamp, and gasket necessary to make the engine track ready. Fully machined and ready for assembly. Just as with all JRPW engines, a custom powder coated engine cover in your choice of color is standard. Instructions and specs are included.


JRPW Pro Upgrade Kit

Created for the racer with an existing engine lacking that extra bit of needed HP. Kit contains our 2018 “Attack Series” Head and carb, matched camshaft, timing key, and all needed gaskets. Cam and timing key selection is made based on your input. Like always, instruction and guidance are provided without charge.



JRPW Big Block Level 10 Cylinder Head

JRPW is proud to introduce their cylinder heads to the big block market. Same expert craftsmanship as our small block heads, just on a larger scale. Fully machined and assembled, this beauty has a 40mm intake valve and a 33 mm exhaust. Includes dual valve springs, retainers and valve locks.


JRPW Big Block Level 5 Cylinder Head

For the milder builds, this head will boost performance in a big way. Same quality of machine work, this model just utilizes the stock valve seats and 36/31mm stainless valves. ready to use, it’s assembled with springs, hd retainers and locks.


JRPW Clone Cylinder Head Level 5

For the smaller modified engines or the stock appearing engines with smaller carbs, this may be the best choice. An oversize intake valve seat is installed along with a 28.5mm stainless valve. Exhaust is a stock diameter stainless valve. Professionally ported and blended, it comes complete with spring package of your choosing, HD retainers and valve locks.


JRPW Clone Cylinder Head Level 5X

This head is a special model with factory 27/25mm valve seats. JRPW performs their magic to make this a significant upgrade, and tops it off with the valve job to make it all work. The head is fully assembled with stainless valves, your choice of springs, and hd retainers and locks.


JRPW Open Animal Cylinder Head

Beginning with the the improved Briggs RT-1 casting, we add the JRPW touch. Stock seats are removed and the pockets are machined to accept 1.25”/ 1.12” machined stainless valves. Ported, blended, and decked to our highest of standards, no stones are left unturned in our quest to provide you with the most possible HP. Includes springs and HD retainers, ready to go.


JRPW Open Clone Cylinder Head Level 10

When all out HP is the goal, this is the only choice. Precision machined with 32/28mm machined stainless valves. Valve bowls are machined and hand blended into the runners.  As with all our heads, seats are precision machined on our state of the art Rottler Seat and Guide machine, leaving a perfect 3 angle seat. Air, air, and more air, thats what this head is all about. Decked out and ready to bolt on, includes dual springs, HD retainers and locks.



JRPW 3” Clone Block

Precision Cylinder sleeve installed, and finish bored and honed to size. Welding and bracing is an additional $85


JRPW 3” Honda Block

Same as above but using the genuine Honda block. Welding and bracing is an additional $85



JRPW Attack Series Blueprinted Clone Carb

Maximum airflow and a matched fuel curve are imperative for any engine to perform at its peak. JRPW Blueprints all carbs to the edge of technical limitations to provide the absolute best performance. Each one is properly jetted and throttle position is set.
Carbs available for all divisions, restricted and unrestricted.

JRPW 390 BP Carb

JRPW machines the internal components and properly jets the carb for your choice of fuel. Same as above but with stock bore size.


JRPW 390 Max Carb

JRPW is pleased to introduce our version of the 390 Honda carb. Bored and machined, this will bolt on lots of HP and still resemble a stock style carb. Gas or Alky. If rules allow, this is an excellent choice. Adapters are at an additional charge


“The 650” Clone Carb

The same precision work as our 690 carbs, but with a smaller bore. Perfect for stock appearing and mild outlaw classes, or any division where the presence of epoxy is disallowed.


“The 690” Clone Carb

The Ultimate in stock body GX 200 carbs, with a .690 bore. Outside epoxy is used because of the huge internal diameter . Every internal part precision machined to provide the highest possible airflow. Alcohol and Gasoline versions available.