This custom-built CY31RC engine, available exclusively at DDM, offers simply amazing performance. 30.5cc's of modified power. 36mm bore, 30mm stroke. Hands-down the best stock (unported) 30.5cc motor available. 4+ horsepower, and 5.5+ horsepower with a tuned pipe. Available in black or chrome, and with or without inner clutch. DDM has taken the hassle out of getting a massive 30.5cc motor - we've custom built them for you. The engine comes fully assembled and ready to bolt-on.
So where does the power come from? We start with a Chung Yang stuffed crank CY29RC engine (35mm bore, 30mm stroke - 28.9cc). The 35mm top-end is removed and set aside. We want a larger, 36mm top-end for increased displacement and power! But the stock 36mm cylinder does not have room for the long 30mm stuffed crankshaft, so ESP has machined out the proper spacing. This is a more efficient and reliable solution than stacking gaskets to achieve the needed space, as there is proper spark plug clearance, the piston ring remains in the well-plated area of the cylinder, and the ignition coil remains properly gapped to the flywheel. The squish band is cut so there will be .020"-.025" of squish (using the stock .020" cylinder gasket), and the combustion chamber is machined to get the compression ratio down to 14:1 for running on premium pump 91 or higher octane gasoline. The head geometry is reshaped to the proven standard 'hemisphere' shaped combustion chamber, and the squish area equals 50% bore area, for more efficient burning. These engines are not ported - the port timing and shape is still stock.
 
For R/C: Fits a wide variety of 1:5 and 1:6 R/C cars, planes, boats, and helicopters. Same mounting dimensions as Zenoah G230RC / G260RC. For cars - fits FG: Marder, Leopard, Monster Beetle, Monster Truck, Stadium Truck, Pajero, Sportsline, etc. Also fits Duratrax Firehammer, Firehammer MT, XTM Grizzly, Carson Attack, HPI Baja 5b, Traxxas Monster Buggy, MCD Rally, MCD Race Runner, MCD 4x4 Monster Truck, and most other large scale onroad and offroad RC cars.

The brand-new 2008 Zenoah G240RC engine is a 22.5cc (32mm bore, 28mm stroke) performance machine. Zenoah took their powerful, reliable G230RC engine and made it even better. Major changes include a 4-bolt cylinder design for improved sealing and reduced gasket blowout (an improvement from the 2-bolt cylinder design of the G230RC); a stronger and lighter crankcase; an additional crankshaft bearing; redesigned cylinder fins for better cooling; larger ports; the high-performance WT-813 carburetor with accelerator pump as standard equipment; a metal-impregnated insulator gasket for a better seal; and modified cylinder hardware to better resist vibration. This engine offers serious performance. It features a 4 transfer port 34mm cylinder, Walbro WT-813 carburetor with accelerator pump (15.88mm bore, 12.7mm venturi, independent high and low jets), lighter flywheel, "hemi"-style combustion chamber, and full-circle crankshaft. Includes installation instructions. Engine is available in complete form, or you can choose purchase the engine without the carb assembly or clutch if you already have these parts and don't need them.

DDM and Earth Surfer Products have teamed up to provide you with a top-quality fully ported 4-BOLT G270RC engine with +2mm stroker (27.2cc). This is not just a a "quick and dirty" 20 minute milling machine port job. ESP ported engines are proven to be fast and reliable. They are fully hand ported from top to bottom by Earth Surfer Products. Your engine will have much more power in all RPMs (even the dead spot that most piped RC engines have before the power hits) and will still REV higher than stock. Earth Surfer products completely tears down the engine and spends hours, cutting in great detail, the porting that will have you grinning from ear to ear. Detail like this is almost impossible to do on a milling machine - even a CNC milling machine. Typical performance gains are in excess of 1 full horsepower increase.

Here is a list of all the work E.S.P. does to the engine. Compare this to other offerings on the market and you will quickly see that DDM and E.S.P. put power in your trigger finger without putting a huge dent in your wallet.
1) Cylinder precision ported (exhaust, intake, and transfers).
2) Polished exhaust port (for smooth flow and low carbon build up) and superb rough finish on the intake, cases, and transfer tunnels for better gas/air mixing.
3) Resurfaced intake, exhaust, and spark plug gasket surface on cylinder to insure no leaks.
4) Perfectly matched cylinder transfer tunnels to cases and case gasket matched.
5) Case porting to insure better flow into the transfer tunnels.
6) Cylinder skirt work to aid flow into the transfer tunnels.
7) New gaskets and piston c-clips.
8) Easy to read carb tuning instructions to get the most reliable power from your engine.
9) E.S.P. logo etched into side of crankcase. See picture.

100% billet reed valve inducted G240RC/G270RC style (4-bolt style cylinder mount) crankcase from legendary 2-stroke engine builder Trevor Simpson. Kit includes billet case with bearings, seals, and gaskets, billet reed valve with 2 carbon fiber petals, mounting hardware, and engraved block-off plate to cover the old cylinder intake (carburetor now mounts to reed valve on the crankcase). Interior case volume has been reduced compared to regular Zenoah cases to increase performance. Gives much more power from low RPM's all the way up to full speed. For ultimate performance, additional gains can be realized with proper cylinder modifications. Compatible with all 4-bolt style RC top ends - fits Zenoah G23LH / G230RC / G260RC / G240RC / G270RC engines. Also fits Chung Yang CY23RC / CY26RC / CY27RC / CY29RC / GP290 engines. Note: these cases have been specially designed to allow for proper clearances when used in RC cars. Fits the HPI Baja 5b. Carburetor position is substantially the same as a stock G230RC; as such, this item should be compatible with most large scale vehicles including FG onroad and offroads, Carson, Traxxas, DuraTrax, XTM, etc. Minor modifications may be needed to make this item work in your application. Also fits Goped brand scooters, just like the original TS 4-bolt billet cases (item dd344).

The brand-new 2008 Zenoah G270RC engine is a 25.4cc (34mm bore, 28mm stroke) performance machine. Zenoah took their powerful, reliable G260RC engine and made it even better. Major changes include a 4-bolt cylinder design for improved sealing and reduced gasket blowout (an improvement from the 2-bolt cylinder design of the G260RC); a stronger and lighter crankcase; an additional crankshaft bearing; redesigned cylinder fins for better cooling; larger ports; the high-performance WT-813 carburetor with accelerator pump as standard equipment; a metal-impregnated insulator gasket for a better seal; and modified cylinder hardware to better resist vibration. This engine offers serious performance. It features a 4 transfer port 34mm cylinder, Walbro WT-813 carburetor with accelerator pump (15.88mm bore, 12.7mm venturi, independent high and low jets), lighter flywheel, "hemi"-style combustion chamber, and full-circle crankshaft. Includes installation instructions. Engine is available in complete form, or you can choose purchase the engine without the carb assembly or clutch if you already have these parts and don't need them.

Note: due to heavy demand, this ESP engine has a lead time of approx 5 days.
This custom-built 27.2cc Zenoah G260RC engine, available exclusively at DDM, offers simply amazing performance and legendary Zenoah quality. 27.2cc's of modified and fully ported power. 34mm bore, 30mm stroke. Get the high-revving benefits of a modified G260RC together with the increased low-end grunt from a longer crankshaft. Aprox 4.25+ horsepower, and 5.5+ horsepower with a tuned pipe. Available in black or chrome, and with or without inner clutch. DDM has taken the hassle out of getting a top-quality modified Zenoah G260RC-based 27.2cc engine - we've custom built them for you. The engine comes fully assembled and ready to bolt-on.
So where does the power come from? We start with a brand-new Zenoah G260RC engine (34mm bore, 28mm stroke - 25.4cc). This is the largest bore Zenoah has available. But we want more displacement for more power, while still keeping the high-quality Zenoah cylinder assembly! So, the stock 28mm crankshaft is removed and set aside. We want a longer 30mm crankshaft for increased displacement and power! But the stock Zenoah 34mm G260RC cylinder does not have room for the long 30mm crankshaft, so ESP has machined out the proper spacing. This is a more efficient and reliable solution than stacking gaskets to achieve the needed space, as there is proper spark plug clearance, the piston ring remains in the well-plated area of the cylinder, and the ignition coil remains properly gapped to the flywheel. The squish band is cut so there will be .020"-.025" of squish (using the stock .020" cylinder gasket), and the combustion chamber is machined to get the compression ratio down to 14:1 for running on premium pump 91 or higher octane gasoline. The head geometry is reshaped to the proven standard 'hemisphere' shaped combustion chamber, and the squish area equals 50% bore area, for more efficient burning.
After the ESP cylinder spacing modifications are complete, ESP then fully ports the engine. ESP completely tears down the engine and spends hours, cutting in great detail, the porting that will have you grinning from ear to ear. Detail like this is almost impossible to do on a milling machine - even a CNC milling machine.
Compare this to other offerings on the market and you will quickly see that DDM and ESP put power in your trigger finger without putting a huge dent in your wallet. Portwork includes:
1) Cylinder precision ported (exhaust, intake, and transfers enlarged and reshaped).
2) Polished exhaust port (for smooth flow and low carbon build up) and superb rough finish on the intake, cases, and transfer tunnels for better gas/air mixing.
3) Resurfaced intake, exhaust, and spark plug gasket surface on cylinder to insure no leaks.
4) Perfectly matched cylinder transfer tunnels to cases and case gasket matched.
5) Case porting to insure better flow into the transfer tunnels.
6) Cylinder skirt work to aid flow into the transfer tunnels.
7) New gaskets and piston c-clips.
8) Easy to read carb tuning instructions to get the most reliable power from your engine.
9) E.S.P. logo etched into side of crankcase. 
For R/C: Fits a wide variety of 1:5 and 1:6 R/C cars, planes, boats, and helicopters. Same mounting dimensions as Zenoah G230RC / G260RC. For cars - fits FG: Marder, Leopard, Monster Beetle, Monster Truck, Stadium Truck, Pajero, Evo, Sportline, etc. For cars - fits FG: Marder, Leopard, Monster Beetle, Monster Truck, Stadium Truck, Pajero, Sportsline, etc. Also fits Duratrax Firehammer, Firehammer MT, XTM Grizzly, Carson Attack, HPI Baja 5b, Traxxas Monster Buggy, MCD Rally, MCD Race Runner, MCD 4x4 Monster Truck, and most other large scale onroad and offroad RC cars.

Note: HPI refers to the CY23RC engine as the "Fuelie". The CY23RC is the stock engine for the Baja 5b.
Chung Yang CY23RC engine (32mm bore, 28mm stroke - 22.5cc) with Walbro WT-668 carb. 2.5 Horsepower. Similar design to the Zenoah G230RC - 4 transfer port 32mm cylinder, single ring piston, double sided finned flywheel, and HP exhaust canister. Ready to bolt-on. All parts are interchangeable with the Zenoah G230RC. Engine is available with or without inner clutch. Engine requires 91 octane (using the R+M/2 octane rating method) or higher fuel, mixed 25:1 with 2-cycle oil (5 ounces per gallon). Engine is available in complete form, or you can choose to purchase the engine without the carb assembly and airfilter if you already have these parts and don't need them.
Available in factory black finish or with chrome shroud, fancover, etc pre-installed.
For scooters: Top speed for this engine with a stock .625 size drive spindle is approx 26 mph. Larger spindles will be faster. Fits Sport, Liquimatic, Bigfoot, X-ped, Super X-ped, Super Bigfoot, Go-Quad, Super Go-Quad, GSR26R, and Homebuilders Kit. Also fits GSR25, GSR26R, GSR29R, Quad 25, and Quad 30 when used together with 54mm clutch assembly.
For R/C: Fits a wide variety of 1:5 and 1:6 R/C cars, planes, boats, and helicopters. Same mounting dimensions as Zenoah G230RC / G260RC. For cars - fits FG: Marder, Leopard, Monster Beetle, Monster Truck, Stadium Truck, Pajero, Sportsline, etc. Also fits Duratrax Firehammer, Firehammer MT, XTM Grizzly, Carson Attack, HPI Baja 5b, Traxxas Monster Buggy, MCD Rally, MCD Race Runner, MCD 4x4 Monster Truck, and most other large scale onroad and offroad RC cars

New - the high-performance "Version 2" GP290 engine from Chung Yang. 36mm bore, 28mm stroke - 28.5cc. Now featuring improved cylinder plating and thicker cylinder walls for improved reliability - the engine now has a larger 40mm cylinder skirt and corresponding crankcase opening (the earlier version was 38mm). This engine offers serious performance. It features a 4 transfer port 36mm cylinder, Walbro WT-668 carburetor (15.88mm bore, 12.7mm venturi, independent high and low jets), "hemi"-style combustion chamber, and full-circle crankshaft. Engine is available in black or chrome finish, and with optional inner clutch. You can also choose to purchase the engine without the carb assembly or airfilter if you already have these parts and don't need them.
Same mounting dimensions as the Zenoah G260RC.
 
For R/C: Fits a wide variety of 1:5 and 1:6 R/C cars, planes, boats, and helicopters. Same mounting dimensions as Zenoah G230RC / G260RC. For cars - fits FG: Marder, Leopard, Monster Beetle, Monster Truck, Stadium Truck, Pajero, Sportsline, etc. Also fits Duratrax Firehammer, Firehammer MT, XTM Grizzly, Carson Attack, HPI Baja 5b, Traxxas Monster Buggy, MCD Rally, MCD Race Runner, MCD 4x4 Monster Truck, and most other large scale onroad and offroad RC cars.

Chung Yang CY29RC engine (35mm bore, 30mm stroke - 28.9cc) with Walbro WT-668 carb, red silicone spark plug cap, and stuffed crankshaft. Stuffed crankshaft reduces crankcase volume, resulting in improved throttle response and engine power. Ready to bolt-on. 3.5+ horsepower. Similar design to the Zenoah G230RC/G260RC - 4 transfer port hp cylinder, single ring piston, double sided finned flywheel, and high-flow muffler. Engine requires 91 octane (using the R+M/2 octane rating method) or higher fuel, mixed 25:1 with 2-cycle oil (5 ounces per gallon). Engine is available in complete form, or you can choose to purchase the engine without the carb assembly or airfilter if you already have these parts and don't need them. Available with or without inner clutch.

For R/C: Fits a wide variety of 1:5 and 1:6 R/C cars, planes, boats, and helicopters. Same mounting dimensions as Zenoah G230RC / G260RC. For cars - fits FG: Marder, Leopard, Monster Beetle, Monster Truck, Stadium Truck, Pajero, Sportsline, etc. Also fits Duratrax Firehammer, Firehammer MT, XTM Grizzly, Carson Attack, HPI Baja 5b, Traxxas Monster Buggy, MCD Rally, MCD Race Runner, MCD 4x4 Monster Truck, and most other large scale onroad and offroad RC cars.

Note: due to heavy demand, this ESP engine has a lead time of approx 5 days.
This custom-built CY31RC engine, available exclusively at DDM, offers simply amazing performance. 30.5cc's of modified and fully ported power. 36mm bore, 30mm stroke. Simply put, this engine is the "king of kings" - it will out-torque and out-rev any other piston port 30.5cc motor. Aprox 4.5+ horsepower, and 6+ horsepower with a tuned pipe. Available in black or chrome, and with or without inner clutch. DDM has taken the hassle out of getting a massive 30.5cc motor - we've custom built them for you. The engine comes fully assembled and ready to bolt-on.
So where does the power come from? We start with a Chung Yang stuffed crank CY29RC engine (35mm bore, 30mm stroke - 28.9cc). The 35mm top-end is removed and set aside. We want a larger, 36mm top-end for increased displacement and power! But the stock 36mm cylinder does not have room for the long 30mm stuffed crankshaft, so ESP has machined out the proper spacing. This is a more efficient and reliable solution than stacking gaskets to achieve the needed space, as there is proper spark plug clearance, the piston ring remains in the well-plated area of the cylinder, and the ignition coil remains properly gapped to the flywheel. The squish band is cut so there will be .020"-.025" of squish (using the stock .020" cylinder gasket), and the combustion chamber is machined to get the compression ratio down to 14:1 for running on premium pump 91 or higher octane gasoline. The head geometry is reshaped to the proven standard 'hemisphere' shaped combustion chamber, and the squish area equals 50% bore area, for more efficient burning.
After the cylinder spacing modifications are complete, ESP then fully ports the engine. ESP completely tears down the engine and spends hours, cutting in great detail, the porting that will have you grinning from ear to ear. Detail like this is almost impossible to do on a milling machine - even a CNC milling machine.
Compare this to other offerings on the market and you will quickly see that DDM and ESP put power in your trigger finger without putting a huge dent in your wallet. Portwork includes:
1) Cylinder precision ported (exhaust, intake, and transfers enlarged and reshaped).
2) Polished exhaust port (for smooth flow and low carbon build up) and superb rough finish on the intake, cases, and transfer tunnels for better gas/air mixing.
3) Resurfaced intake, exhaust, and spark plug gasket surface on cylinder to insure no leaks.
4) Perfectly matched cylinder transfer tunnels to cases and case gasket matched.
5) Case porting to insure better flow into the transfer tunnels.
6) Cylinder skirt work to aid flow into the transfer tunnels.
7) New gaskets and piston c-clips.
8) Easy to read carb tuning instructions to get the most reliable power from your engine.
9) E.S.P. logo etched into side of crankcase

New! 2006 model Chung Yang CY29RC headkit engine (35mm bore, 30mm stroke - 28.9cc) with Walbro WT-668 carburetor. The 2006 model features a red spark plug cap, a rubber kill switch cover, improved cylinder plating, and a high-polish finish on the billet head! Includes 54mm inner clutch assembly pre-installed. Includes choice of spiral billet head shell with 14:1 compression dome. Ready to bolt-on. 3.75 horsepower. Similar design to the Zenoah G230RC/G260RC - 4 transfer port hp cylinder, single ring piston, double sided finned flywheel, etc. Engine requires 91 octane (using the R+M/2 octane rating method) or higher fuel, mixed 25:1 with 2-cycle oil (5 ounces per gallon).

Genuine Zenoah complete gasket set and carb spacer for Zenoah G230RC / G260RC engines. Also fits Chung Yang CY23RC / CY26RC / CY27RC / CY29RC / GP290 engines. Kit is made up of 1 each of DDM part# AV501, AV506, FD223, DD252, CA321 & AV514

High-compression, reuseable thin copper cylinder gasket. Fits Zenoah G240RC / G270RC / G231PUH / G260PUH / G260PU / G231PUM / G260PUM engines (i.e. 4-bolt cylinder style engines). Also fits TS 4-bolt billet crankcases. Copper gasket is .012" (0.30mm) thick - stock gasket is .020" (0.50mm) thick. Installing this gasket reduces the squish clearance in your engine - usually the easiest way to increase power and reliability of a small 2-stroke engine. You should experience a noticable improvement in low end torque and throttle response as well as slightly increased top end RPMs. DDM recommends using 95 octane or higher fuel after installing this gasket.

Chung Yang high performance 36mm piston kit. Piston has proper cam and taper for better fit in bore at operating temperatures, resulting in longer life and better ring seal. Improved skirt cutout for increased transfer port flow. Ring is made from nodular iron for durability and longevity. Kit includes piston, ring, piston pin, circlips, pin bearing, and washers. Fits GP290 engines and engines with 36mm big-bore kits or headkits.

Chung Yang high performance 32mm piston kit. Piston has proper cam and taper for better fit in bore at operating temperatures, resulting in longer life and better ring seal. Improved skirt cutout for increased transfer port flow. Ring is made from nodular iron for durability and longevity. Kit includes piston, ring, piston pin, circlips, pin bearing, and washers. Fits G230RC / G231PUH / G231PUM / CY23RC engines.

Chung Yang high performance 35mm piston kit. Piston has proper cam and taper for better fit in bore at operating temperatures, resulting in longer life and better ring seal. Improved skirt cutout for increased transfer port flow. Ring is made from nodular iron for durability and longevity. Kit includes piston, ring, piston pin, circlips, pin bearing, and washers. Fits CY27RC / CY29RC engines and engines with 35mm big-bore kits or headkits

These big-bore kits have been race ported - intake, exhaust, and transfer ports have been enlarged/reshaped for more fuel/air flow and hence more power. In addition, the piston has been slightly milled to reduce the chances of seizure. Chung Yang 35mm big-bore kit - 26.9cc. It features an all-new casting with thicker heat fins and more. Kit includes: cylinder, 35mm piston, piston ring, piston pin, pin washer set, pin bearing, and NGK CMR7H spark plug. Increases power and speed substantially! This high-performance product requires 91 octane (using the R+M/2 octane rating method) or higher fuel, and comes without warranty. Fits Zenoah G23LH / G230RC / G260RC engines. Also fits Chung Yang CY23RC / CY26RC / CY27RC engines.

These big-bore kits have been race ported - intake, exhaust, and transfer ports have been enlarged/reshaped for more fuel/air flow and hence more power. In addition, the piston has been slightly milled to reduce the chances of seizure. 35mm bore and 30mm stroke - effective displacement of 28.9cc! Kit includes: CY 35mm cylinder, 35mm piston, piston ring, piston pin, pin washer set, pin bearing, circlips, CMR7H spark plug, cylinder gasket, and choice of +2mm stroker crankshaft (30mm total stroke). The squish on the cylinder has been pre-machined to accept the 2mm stroker crankshaft using only the standard 1 base gasket. Provides HUGE increases in engine power, allowing you to use taller gearing for more top speed! This high-performance product requires 91 octane (using the R+M/2 octane rating method) or higher fuel, and comes without warranty. Fits Zenoah G23LH / G230RC / G260RC engines. Fits Chung Yang CY23RC / CY26RC / CY27RC engines.

If displacement is what you crave, look no further. This ESP modified & DDM Race Ported big-bore combo kit will allow you to convert your current engine into a 30.5cc performance monster. Feel the power that only a larger engine can provide. This kit is a TORQUE MONSTER, with killer low end and midrange power.
ESP modifies this cylinder by machining at the head. The stock 36mm cylinder does not have room for the longer crankshaft in this kit, so ESP has machined out the proper spacing. This is a more efficient and reliable solution than stacking gaskets to achieve the needed space, as there is proper spark plug clearance and the piston ring remains in the well-plated area of the cylinder. The squish band is cut so there will be .020"-.025" of squish (using the stock .020" cylinder gasket), and the combustion chamber is machined to get the compression ratio down to 14:1 for running on premium pump 91 or higher octane gasoline. The head geometry is reshaped to the proven standard 'hemisphere' shaped combustion chamber, and the squish area equals 50% bore area, for more effiecient burning. These ESP modified cylinders are then race ported by DDM - intake, exhaust, and transfer ports have been enlarged/reshaped for more fuel/air flow and hence more power. In addition, the piston has been slightly milled to reduce the chances of seizure.Kit includes ESP modified + DDM ported 36mm cylinder, 36mm piston, piston ring, piston pin and two pin washers, circlips, two cylinder bolts, insulator gasket, and CMR7H spark plug. Increases your engine displacement to 30.5cc (36mm bore) when used with a 30mm stroke crankshaft. This kit is not recommended for use with a 28mm or 29mm stroke crankshaft, as the modifications are specially tailored to work with a 30mm stroke. Increases engine power SUBSTANTIALLY - estimated engine power output is 4.3+ HP. This high-performance product requires 91 octane (using the R+M/2 octane rating method) or higher fuel, and comes without warranty. Fits Zenoah G23LH / G230RC / G260RC engines when a +2mm (30mm total stroke) crankshaft is added. Also fits Chung Yang CY23RC / CY26RC / CY27RC / GP290 engines when a +2mm (30mm total stroke) crankshaft is added. Bolts directly on to Chung Yang CY29RC engines, as this engine features a 30mm stroke crankshaft as stock. Bottom line - to install this kit on any engine except a CY29RC, you must purchase a +2mm crankshaft.
For Scooters: Fits any scooter using one of the above engines. Fits Sport, Liquimatic, Bigfoot, X-ped, Super X-ped, Super Bigfoot, Go-Quad, Super Go-Quad, Go-Quad 30, GSR26R, GSR29R, and Homebuilders Kit.
For R/C: Fits a wide variety of 1:5 and 1:6 R/C cars, planes, boats, and helicopters. Same mounting dimensions as Zenoah G230RC / G260RC. For cars - fits FG: Marder, Leopard, Monster Beetle, Monster Truck, Stadium Truck, and Pajero. Also fits Smartech Traveler, Firehammer, XTM, Carson Attack, HPI Baja 5b, and other large scale RC cars. Must be used together with a 30mm stroke crankshaft

These big-bore kits have been race ported - intake, exhaust, and transfer ports have been enlarged/reshaped for more fuel/air flow and hence more power. In addition, the piston has been slightly milled to reduce the chances of seizure. If displacement is what you crave, look no further. This custom DDM big-bore combo kit will allow you to convert your current engine into a race ported 30.5cc performance monster. Feel the power that only a larger engine can provide. Kit includes race ported 36mm cylinder, modified 36mm piston, piston ring, piston pin and two pin washers, circlips, two cylinder bolts, insulator gasket, CMR7H spark plug, choice of 30mm stroke crankshaft, and .040" copper cylinder gasket. Increases your engine displacement to 30.5cc (36mm bore, 30mm stroke). Increases engine power SUBSTANTIALLY - estimated engine power output is 4.25+ HP. This high-performance product requires 91 octane (using the R+M/2 octane rating method) or higher fuel, and comes without warranty. Fits Zenoah G23LH / G230RC / G260RC engines. Also fits Chung Yang CY23RC / CY26RC / CY27RC / CY29RC / GP290 engines.
 
For R/C: Fits a wide variety of 1:5 and 1:6 R/C cars, planes, boats, and helicopters. Same mounting dimensions as Zenoah G230RC / G260RC. For cars - fits FG: Marder, Leopard, Monster Beetle, Monster Truck, Stadium Truck, and Pajero. Also fits Smartech Traveler, Firehammer, XTM, Carson Attack, HPI Baja 5b, and other large scale RC cars.

These big-bore kits have been race ported - intake, exhaust, and transfer ports have been enlarged/reshaped for more fuel/air flow and hence more power. 34mm big bore cylinder kit for CY23RC, G23LH, and G230RC engines. Also works as a replacement top end for G260RC and CY26RC engines. Includes cylinder, piston, ring, piston pin, circlips, base gasket, and spark plug. Increases displacement to 25.4cc (34mm bore). Increases engine power and speed SUBSTANTIALLY! This high-performance product requires 91 octane (using the R+M/2 octane rating method) or higher fuel, and comes without warranty. Note: if installing this product onto a Chung Yang engine (CY23RC, CY26RC, etc), you will need to use a Zenoah pin bearing (ca217) and Zenoah pin washers (ca216).