{"product_id":"gy6-172cc-61mm-scooter-performance-kit-and-kaboodle-copy-1","title":"GY6 171cc Big Bore Kit + Head + Cam (Fits QMJ157)","description":"\u003c!-- QUICK PITCH --\u003e\n\u003cp style=\"font-size: 17px; line-height: 1.5;\"\u003eAll the performance you need in one kit. We've spent years testing other big bore kits on the market — keeping what worked, fixing what didn't. Built with premium rings, gaskets, springs, and metals, this is a true no-case-boring, drop-in big bore kit — the largest you can run on a GY6 A motor (QMJ157) without boring your cases. As the saying goes: there's no replacement for displacement.\u003c\/p\u003e\n\u003c!-- FITMENT --\u003e\n\u003cdiv style=\"border: 1px solid #121212; padding: 18px 20px; border-radius: 0; margin: 20px 0;\"\u003e\n\u003cp style=\"font-size: 13px; font-weight: bold; text-transform: uppercase; letter-spacing: 0.04em; margin: 0 0 12px;\"\u003e🔍  Does this fit your bike?\u003c\/p\u003e\n\u003cul style=\"margin: 0; padding-left: 20px; font-size: 15px; line-height: 1.6;\"\u003e\n\u003cli\u003e\n\u003cstrong\u003e171cc \/ 172cc, 12:1 compression\u003c\/strong\u003e — for the GY6 A motor (QMJ157) only. \u003cstrong\u003e54mm stud spacing.\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits most QMJ157 engines, but not all.\u003c\/strong\u003e Watch the install video on this listing before ordering — we walk through the specific engines this won't work on and why.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eDrop-in fit — no case boring required.\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBuggy\/go-kart owners:\u003c\/strong\u003e fitment hasn't been fully confirmed across every GY6 engine variant used in buggies. This is a buy-at-your-own-risk purchase — see below.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c!-- BEFORE YOU ORDER --\u003e\n\u003cdiv style=\"border: 1px solid #121212; padding: 18px 20px; border-radius: 0; margin: 20px 0;\"\u003e\n\u003cp style=\"font-size: 13px; font-weight: bold; text-transform: uppercase; letter-spacing: 0.04em; margin: 0 0 12px;\"\u003e⚠️  Before you order\u003c\/p\u003e\n\u003cul style=\"margin: 0; padding-left: 20px; font-size: 15px; line-height: 1.6;\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo returns on performance parts\u003c\/strong\u003e — especially relevant given the fitment note above.\u003c\/li\u003e\n\u003cli\u003eYou'll need to choose \u003cstrong\u003eforged or cast piston\u003c\/strong\u003e in the dropdown — that's the one decision this kit asks you to make. Forged is recommended for you weekend warriors. Cast is for you everyday riders.\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eThe piston ring end gaps are \u003cstrong\u003epre-measured and pre-installed\u003c\/strong\u003e into the cylinder for you. \u003cstrong\u003eDo not remove the piston from the cylinder\u003c\/strong\u003e — this can bend the rings during reinstall and require you to buy new ones. If you need to install the piston pin, slide the piston down just far enough to do that without exposing the rings.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eUse super unleaded fuel only.\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c!-- WHAT'S INCLUDED --\u003e\n\u003cdiv style=\"border: 1px solid #121212; padding: 18px 20px; border-radius: 0; margin: 20px 0;\"\u003e\n\u003cp style=\"font-size: 13px; font-weight: bold; text-transform: uppercase; letter-spacing: 0.04em; margin: 0 0 12px;\"\u003e✓  What's in the box\u003c\/p\u003e\n\u003cul style=\"margin: 0; padding-left: 20px; font-size: 15px; line-height: 1.6;\"\u003e\n\u003cli\u003eCylinder kit (forged or cast piston — your choice)\u003c\/li\u003e\n\u003cli\u003eBig valve head\u003c\/li\u003e\n\u003cli\u003eProBld performance camshaft (built for low-end and mid-range power)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c!-- WHY THIS KIT --\u003e\n\u003cp style=\"font-size: 15px; line-height: 1.6;\"\u003eYou'll find similar-looking kits online for half the price — those are made in China. This one's made in Taiwan, and the quality difference is real.\u003c\/p\u003e\n\u003c!-- TUNING RESOURCES --\u003e\n\u003cp style=\"font-size: 15px; line-height: 1.6;\"\u003eAdd a \u003ca href=\"https:\/\/www.rollingwrenchdenver.com\/products\/wide-band-o2-sensor-tuning-kit\"\u003e\u003cstrong\u003ewideband O2 sensor kit\u003c\/strong\u003e\u003c\/a\u003e to make tuning this a breeze. For torque specs once you're ready to assemble, check our \u003ca href=\"https:\/\/www.rollingwrenchdenver.com\/blogs\/news\/gy6-torque-settings?srsltid=AU7gw4Us81FErIDK0PSCyVfouoyN4rWdIhkVsAhDZfUMpOCDKaIhrdL6\"\u003e\u003cstrong\u003eGY6 torque settings guide\u003c\/strong\u003e\u003c\/a\u003e.\u003c\/p\u003e\n\u003c!-- INSTALL VIDEO --\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003c!-- Paste your existing install video embed here --\u003e","brand":"Rolling Wrench","offers":[{"title":"Rolling Wrench Cast Piston + Head + Cam","offer_id":67595569725669,"sku":"P-3 + P-2 + O-2-5","price":505.0,"currency_code":"USD","in_stock":false},{"title":"ProBld Forged Piston + Head + Cam","offer_id":67595569856741,"sku":"P-4 + P-2 + O-2-5","price":569.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1415\/0180\/files\/097F7170-B416-4F5E-B8A8-B4DA6A60721A_40f49448-8f3b-4813-9557-3c6d4ba6b94c.heic?v=1790807787","url":"https:\/\/www.rollingwrenchdenver.com\/products\/gy6-172cc-61mm-scooter-performance-kit-and-kaboodle-copy-1","provider":"Rolling Wrench","version":"1.0","type":"link"}