{"title":"Pit Bike Top End Rebuild Kits","description":"\u003cdiv class=\"category-top-desc\"\u003e\n\u003cp\u003eTop end piston kits \u0026amp; cylinder kits for KTM 50 SX, Honda CT70, Yamaha PW50 \u0026amp; more\u003c\/p\u003e\n\u003cp\u003eStock bore replacement and performance upgrade options for 50cc \u0026amp; small bore pit bikes\u003c\/p\u003e\n\u003c\/div\u003e","products":[{"product_id":"performance-camshaft-for-honda-crf50","title":"Performance Camshaft for Honda CRF50","description":"\n\u003cp\u003e\u003cstrong\u003e50 Caliber Racing High Performance Race Camshaft for Honda CRF50 Pit Bikes\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003ePerformance camshaft with much more aggressive lift and duration. Increase power with a simple camshaft change. For STOCK or RACE head 92-up Honda pit bikes. Goes well with 88cc big bore kits and aftermarket CDI.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eSpecs:\u003c\/strong\u003e\u003cbr\u003e- .235″ intake valve lift and 196 degrees of duration @ 050″, .218″ exhaust valve lift and 208 degrees of duration @ .050″\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFits the following Honda pit bikes: \u003c\/strong\u003e\u003cbr\u003e- CRF50 (2004-2018)\u003cbr\u003e- CRF70 (2004-2018)\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236485177601,"sku":"4448A12","price":55.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/6906.jpg?v=1780777660"},{"product_id":"oil-seal-kit-50cc-gy6-engine-39mm-bore","title":"Oil Seal Kit 50cc GY6 Engine - 39mm Bore","description":"\u003cp\u003e\u003cstrong\u003eScooterX Replacement Oil Seals for 50cc GY6 Enginese with 39mm Cylinder Bore\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e Brand new oil seals for 50cc GY6 engines. These motors are commonly used in gas scooters, go karts, dune buggies, pocket bikes, and more. Fits 39mm bore, 50cc size GY6 engines. See below for dimensions:\u003cbr\u003e\u003cbr\u003e \u003cstrong\u003eDimensions:\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e - (2) 30mm OD x 16mm ID x 5mm W\u003cbr\u003e - (1) 42mm OD x 27mm ID x 7mm W\u003cbr\u003e - (1) 30mm OD x 16mm ID x 6mm W\u003cbr\u003e\u003cbr\u003e \u003cstrong\u003eCOMPATIBLE WITH THE FOLLOWING:\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e Baja\u003cbr\u003e - SC50\u003cbr\u003e\u003cbr\u003e Bintelli\u003cbr\u003e - Breeze 50\u003cbr\u003e - Sprint 50\u003cbr\u003e\u003cbr\u003e Panterra\u003cbr\u003e - Freedom 50\u003cbr\u003e - Fusion 50\u003cbr\u003e - Retro 50\u003cbr\u003e\u003cbr\u003e Roketa\u003cbr\u003e - All 50cc Scooter Models\u003cbr\u003e\u003cbr\u003e Schwinn\u003cbr\u003e - Hope 50\u003cbr\u003e - Laguna 50\u003cbr\u003e\u003cbr\u003e Twist N' Go\u003cbr\u003e - Venice 49cc\u003cbr\u003e - LS 49cc\u003cbr\u003e - Milano 50\u003cbr\u003e\u003cbr\u003e Wolf\u003cbr\u003e - Islander 50\u003cbr\u003e - Jet 50\u003cbr\u003e - Lucky 50\u003cbr\u003e - RX-50\u003cbr\u003e\u003cbr\u003e Will also many more unlisted makes\/models. Just make sure you have a 39mm bore GY6 engine and it will fit!\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236488225025,"sku":"4420","price":16.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/8859.jpg?v=1780778368"},{"product_id":"oil-seal-kit-150cc-gy6-engine","title":"Oil Seal Kit 150cc GY6 Engine","description":"\u003cp\u003e\u003cstrong\u003eScooterX Replacement Oil Seals for 125cc-150cc GY6 Engines\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003eScooterX Replacement Oil Seals for 125-150cc GY6 Engines. Brand new oil seals for long case GY6 engines. These motors are commonly used in pit bikes, go karts and atvs. See below for dimensions:\u003cbr\u003e\u003cbr\u003e \u003cstrong\u003eDimensions:\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e- (2) 30mm OD x 19mm ID x 5mm W\u003cbr\u003e- (1) 42mm OD x 27mm ID x 7mm W\u003cbr\u003e- (1) 30mm OD x 19mm ID x 6mm W\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236488257793,"sku":"4421","price":16.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/8861.jpg?v=1780778381"},{"product_id":"ktm-50-sx-piston-kit-standard-bore","title":"KTM 50 SX Piston Kit Standard Bore","description":"\u003cp\u003e\u003cstrong\u003e50 Caliber Racing Replacement Standard Bore Piston Kit for KTM 50 Liquid Cooled Pit Bikes\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e Brand new top quality piston kit for KTM 50cc Pit Bikes with liquid cooled engine. Will not work on air cooled models. Stock bore size and compression ratio. Complete assembly including piston, wrist pin, needle bearing, ring and clips. Our kits are high quality, complete and ready to build right out of the box. You'll be able to take confidence that you'll have the precision components you need to get your toys running again, the right way. Be a superdad and fix your kid's bike!\u003cbr\u003e\u003cbr\u003e \u003cstrong\u003eSpecifications:\u003c\/strong\u003e\u003cbr\u003e - Includes piston, ring, circlips, wrist pin, bearing\u003cbr\u003e - Standard bore size and compression\u003cbr\u003e - Fits Liquid cooled bikes only\u003cbr\u003e - Manufactured to OEM Spec\u003cbr\u003e\u003cbr\u003e \u003cstrong\u003eWill fit the following KTM 50cc dirt bikes:\u003c\/strong\u003e\u003cbr\u003e - Junior LC (2002-2008)\u003cbr\u003e - Senior LC (2002-2008)\u003cbr\u003e - Pro Junior LC (2002-2008\u003cbr\u003e - Pro Senior LC (2002-2008)\u003cbr\u003e\u003cbr\u003e *Will \u003cstrong\u003eNOT\u003c\/strong\u003e fit some 2002, or 2001 and older KTM50 with Morini Franco manufactured engine. \u003cstrong\u003eLiquid cooled only.\u003c\/strong\u003e\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236793065729,"sku":"4457A1","price":34.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/6927.jpg?v=1780790194"},{"product_id":"yamaha-pw50-big-bore-kit-60cc-with-head","title":"Yamaha PW50 Big Bore Kit 60cc With Head","description":"\u003cp\u003e\u003cstrong\u003e50 Caliber Racing 60cc Big Bore Top End Kit with Head Included for Yamaha PW50 \u0026amp; QT50 Pit Bikes\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e Bolt on 60cc Big Bore Kit for Yamaha PW50 and QT50 Pit Bikes. Ready to install out of the box, includes all gaskets and components necessary to rebuild your top end. Our kits are complete, high quality and will extend the life of your toys for many more years of enjoyment. This kit can be installed by anyone with basic mechanical skills that is not afraid to turn some nuts and bolts. Breathe new life into your bike with our high quality, affordable and reliable big bore kit!\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eKit Includes:\u003c\/strong\u003e\u003cbr\u003e - 1 Cylinder\u003cbr\u003e - 1 Cylinder Head\u003cbr\u003e - 1 Piston\u003cbr\u003e - 2 Piston Rings\u003cbr\u003e - 2 Circlips\u003cbr\u003e - 1 Piston Pin\u003cbr\u003e - 1 Head Gasket\u003cbr\u003e - 1 Base Gasket\u003cbr\u003e - 1 Pin Bearing\u003cbr\u003e - 4 Cylinder Studs\u003cbr\u003e - 4 Stud Nuts\u003cbr\u003e - 1 Spark Plug\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFits the following Yamaha models:\u003c\/strong\u003e\u003cbr\u003e PW50 Y-Zinger Peewee 50 (1981-2018)\u003cbr\u003e QT50 Yamahopper (1979-1987)\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236796473601,"sku":"4449B1","price":89.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/6909.jpg?v=1780790323"},{"product_id":"honda-xr400-trx400-top-end-cylinder-kit","title":"Honda XR400 TRX400 Top End Cylinder Kit Stock Bore","description":"\u003cdiv class=\"prod-desc\"\u003e\n\u003ch2\u003eHonda XR400 and TRX400 Top End Cylinder Kit – Stock Bore Performance\u003c\/h2\u003e\n\u003cp\u003eRestore power and reliability with this complete 50 Caliber Racing top end cylinder kit designed for Honda XR400 and TRX400EX models. Built to OEM specifications, this stock bore kit provides proper fitment, dependable performance, and long service life. It is an ideal solution for riders looking to rebuild worn engines and bring back factory performance.\u003c\/p\u003e\n\u003cp\u003eThis kit includes all major components needed to complete a top end rebuild, helping reduce downtime and eliminate the need to source parts separately. The included moly coated piston helps reduce friction and heat while supporting durability and smooth engine operation. Designed for straightforward installation, this kit allows you to complete your rebuild with confidence.\u003c\/p\u003e\n\u003cp\u003eWhether you are maintaining your trail machine or restoring performance, this complete top end kit is engineered for consistent reliability and long-term use.\u003c\/p\u003e\n\u003ch2\u003eKit Includes\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCylinder jug\u003c\/li\u003e\n\u003cli\u003eMoly coated piston – 85mm, 10:1 compression\u003c\/li\u003e\n\u003cli\u003ePiston ring set\u003c\/li\u003e\n\u003cli\u003eCirclips\u003c\/li\u003e\n\u003cli\u003eWrist pin\u003c\/li\u003e\n\u003cli\u003eSpark plug\u003c\/li\u003e\n\u003cli\u003eComplete gasket set\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFits the Following Honda Models\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eXR400R (1996–2004)\u003c\/li\u003e\n\u003cli\u003eTRX400EX (1999–2009)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eDesigned for durability and ease of installation, this top end rebuild kit helps extend engine life and restore dependable performance.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236796899585,"sku":"4449A6","price":95.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/6920.jpg?v=1780790339"},{"product_id":"race-head-v2-upgrade-for-lifan-150cc-160cc-yx-gpx","title":"Race Head V2 Upgrade for Lifan 150cc 160cc YX GPX","description":"\u003cp\u003e\u003cstrong\u003e150\/160cc YX\/GPX Race Head V2 Upgrade Kit:\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003eThis kit from 50 Caliber Racing is to upgrade the cylinder head on stock YX\/GPX 150 or 160 engines to our new Race Head V2. The addition of this new head will dramatically increase the performance of your stock engine! This kit includes our new Race Head V2 and while the new head may appear to be the same on the outside as our other KLX110 type race head, internally it has gone through numerous changes. The addition of roller rocker arms and a new camshaft are the biggest changes followed by bigger valves and ports. The exhaust valve is now stainless as well (21-4N material). This all adds up to a cylinder head that puts out a professional level of performance yet is still affordable for the privateer rider. Also, included is a piston with bigger reliefs to match the larger valves of the new race head. Additionally, our head gasket kit includes a head o-ring set and exhaust gasket so you don't have to re-use your old ones or make a trip to your local dealer to get new ones and spend more money. These are high quality parts and require no machining to the cases or other modifications - bolt on and go!\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIncludes:\u003c\/strong\u003e\u003cbr\u003e- Race Head V2 - Roller rockers, 30mm intake valve, 24.5mm exhaust valve, 27mm intake port, 23mm exhaust port (valves installed).\u003cbr\u003e- Race Camshaft for Race Head V2.\u003cbr\u003e- Lightweight high compression domed 60mm piston with rings, pin, \u0026amp; clips.\u003cbr\u003e- Head gasket kit - includes the cylinder head o-ring set and an exhaust gasket.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFits:\u003c\/strong\u003e\u003cbr\u003e- YX 150cc or 160cc engines\u003cbr\u003e- GPX 150cc or 160cc engines\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003e**Note:\u003c\/strong\u003e There are no installation instructions, but if you can replace your piston, you can install this kit. If you don't have any experience working on your engine, we highly recommend having a professional technician install this kit. The parts are installed in the same manner as OEM parts.\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236797784321,"sku":"5150","price":359.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/3383.jpg?v=1780790372"},{"product_id":"47mm-piston-kit-honda-ct70-atc70-sl70","title":"47mm Piston Kit Honda CT70  ATC70 SL70","description":"\u003cp\u003e\u003cstrong\u003e50 Caliber Racing 47mm Standard Bore Piston Kit for Honda C70 CT70 CL70 SL70 XL70 ATC70\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e Piston Kit with Standard Bore for Honda 70cc vintage pit bikes. Complete assembly including 47mm piston, wrist pin, rings and circlips. Replaces oem Honda part number 13101-087-000. Our kits are high quality, complete and ready to build right out of the box. You'll be able to take confidence that you'll have the precision components you need to get your toys running again, the right way. Be a superdad and fix your kid's bike!\u003cbr\u003e\u003cbr\u003e \u003cstrong\u003eSpecifications:\u003c\/strong\u003e\u003cbr\u003e - Includes 47mm piston, rings, wrist pin, \u0026amp; circlips\u003cbr\u003e - Standard bore size and compression\u003cbr\u003e - Replaces OEM part # 13101-087-000\u003cbr\u003e - Manufactured to OEM Spec\u003cbr\u003e - Please note gray rings go on top!\u003cbr\u003e\u003cbr\u003e \u003cstrong\u003eFits the following Honda Models:\u003c\/strong\u003e\u003cbr\u003e - C70 (1970-1983)\u003cbr\u003e - CL70 (1969-1973)\u003cbr\u003e - CT70 (1969-1982)\u003cbr\u003e - SL70 (1971-1973)\u003cbr\u003e - XL70 (1976)\u003cbr\u003e - ATC70 (1978-1985)\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236797817089,"sku":"4448A26","price":45.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/8435.jpg?v=1780790383"},{"product_id":"high-volume-oil-pump-vintage-honda-69-81-z50","title":"High Volume Oil Pump - Vintage Honda 69-81 Z50","description":"\u003cp\u003e\u003cstrong\u003eHigh Volume Oil Pump - Vintage Honda Z50\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003e High volume oil pump for vintage Honda pit bikes and small ATVs. Delivers up to 3x the volume as the stock pump. We highly recommend upgrading your oil system when installing a big bore kit. Installation requires a 2mm drill-out of the oiling outlet.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFits:\u003c\/strong\u003e\u003cbr\u003e - Z50 (1969-1981)\u003cbr\u003e - CT70 (Up to 1981)\u003cbr\u003e - SL70 (Up to 1981)\u003cbr\u003e - XL70 (Up to 1981)\u003cbr\u003e - ATC70 (Up to 1981)\u003cbr\u003e - TRX70 (Up to 1981)\u003cbr\u003e\u003cbr\u003e ** Note - Installation requires a 2mm drill-out of the oiling outlet.\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236802208001,"sku":"5122","price":32.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/5091.jpg?v=1780790554"},{"product_id":"honda-z50-performance-camshaft-1968-1981","title":"Honda Z50 Performance Camshaft 1968-1981","description":"\u003cp\u003e\u003cstrong\u003e50 Caliber Racing Performance Camshaft for Vintage Honda Z50 Pit Bikes and 70cc ATVs\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThis is a much more aggressive camshaft compared to the stock. Will increase power on a stock engine, and even better power can be made with a big bore modified engine up to 88cc. Works with a stock head.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003cstrong\u003eFits:\u003c\/strong\u003e\u003cbr\u003e - Z50 (1969-1981)\u003cbr\u003e - CT70 (Up to 1981)\u003cbr\u003e - SL70 (Up to 1981)\u003cbr\u003e - XL70 (Up to 1981)\u003cbr\u003e - ATC70 (Up to 1981)\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236812824833,"sku":"5640","price":60.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/7888.jpg?v=1780790876"},{"product_id":"high-volume-oil-pump-honda-pit-bikes-1982-up","title":"High Volume Oil Pump - Honda Pit Bikes 1982-Up","description":"\n\u003cp\u003e\u003cstrong\u003e50 Caliber Racing High Volume Oil Pump - Honda Pit Bikes CRF50 XR50 CRF70 XR70\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003eHigh volume oil pump for Honda 50cc Pit Bikes. Delivers up to 3 times the flow of the stock pump, which will help reduce wear and prolong the life of your engine. This pump is highly recommended when installing a big bore kit. Includes pump and gasket.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFeatures\u003c\/strong\u003e:\u003cbr\u003e- Prolong the life of your engine\u003cbr\u003e- Recommended when installing big bore kit\u003cbr\u003e- Pump and gasket included\u003cbr\u003e- Delivers 3x the volume of stock pump\u003cbr\u003e- Requires 2mm drill out of oiling outlet\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFits the following Honda pit bikes:\u003c\/strong\u003e\u003cbr\u003e- Z50 (1982-1999)\u003cbr\u003e- CT70 (1982-1994)\u003cbr\u003e- XR50 (2000-2003)\u003cbr\u003e- CRF50 (2004-2023)\u003cbr\u003e- XR70 (1997-2003)\u003cbr\u003e- CRF70 (2004-2023)\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e*Note:\u003c\/strong\u003e Installation requires 2mm drill out of oiling outlet\u003c\/p\u003e","brand":"50 Caliber Racing","offers":[{"title":"Default Title","offer_id":49236966998273,"sku":"5121","price":26.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0816\/8256\/3329\/files\/6695.jpg?v=1780803112"}],"url":"https:\/\/utvdude.com\/collections\/pit-bike-top-end-rebuild-kits.oembed","provider":"UTV Dude","version":"1.0","type":"link"}