# TBParts 88cc Big Bore Kit, Race Cam and 20mm Carb Kit for Z50 CRF50 XR50 88-Present > This is a plain-text (markdown) copy of a page on tboltusa.com, made for AI assistants. People see the same page at the HTML link below. - **Breadcrumbs:** [Home](https://tboltusa.com/store/index.md) > [Japanese Mini Bike Parts](https://tboltusa.com/store/japanese-mini-bike-parts-c-100.md) > [CRF50 Z50 & XR50](https://tboltusa.com/store/japanese-mini-bike-parts-crf50-z50-xr50-c-100_122.md) > [Big Bore & Engine Kits](https://tboltusa.com/store/crf50-z50-xr50-big-bore-engine-kits-c-100_122_124.md) > TBParts 88cc Big Bore Kit, Race Cam and 20mm Carb Kit for Z50 CRF50 XR50 88-Present - **Web page:** [this page on tboltusa.com](https://tboltusa.com/store/tbparts-88cc-big-bore-kit-race-cam-and-20mm-carb-kit-for-z50-crf50-xr50-88-present-p-396.html) - **Markdown:** [this page as markdown](https://tboltusa.com/store/tbparts-88cc-big-bore-kit-race-cam-and-20mm-carb-kit-for-z50-crf50-xr50-88-present-p-396.md) - **Generated:** 2026-11-10 13:05 EST - **Site guide for AI assistants:** [llms.txt](https://tboltusa.com/llms.txt) - **Your list:** To list everything you have looked at in one page, with current prices and stock, add ids to this address (comma separated, up to 20 of each): `https://tboltusa.com/store/seen.md?p=396` All prices are in US dollars (USD). Shipping and any tax are worked out at checkout. ## Summary - **Part number:** TBW0930 - **Price:** $269.99 USD - **Stock:** Out of stock. It cannot be added to the cart right now. A person can ask to be emailed when it is back: [Get on the List](https://tboltusa.com/store/contact_us.php?pid=396&stockcheck=true) ([Contact us](https://tboltusa.com/store/contact_us.md)) This is a kit: the count is how many complete kits can be built from the parts on hand. - **Reviews:** [1 reviews, average 4 of 5](https://tboltusa.com/store/reviews/tbparts-88cc-big-bore-kit-race-cam-and-20mm-carb-kit-for-z50-crf50-xr50-88-present-pr-396.html) - **Product id:** 396 - **Product last changed:** 2025-06-03 ## What it fits The store lists a part under each bike or engine model it is meant for (the categories below) and may name models in the description. Do not assume it fits a bike or engine that is not named here; ask the store first. - [Japanese Mini Bike Parts > CRF50 Z50 & XR50 > Big Bore & Engine Kits](https://tboltusa.com/store/crf50-z50-xr50-big-bore-engine-kits-c-100_122_124.md) - [TB Parts > CRF50 XR50 Z50 88-Up > CRF50 XR50 Z50 Big Bore and Stroker kits 1988 UP](https://tboltusa.com/store/crf50-xr50-z50-88-up-crf50-xr50-z50-big-bore-and-stroker-kits-1988-up-c-68_73_982.md) - [TB Parts > Z50 88-99 > Z50 88-99 Big Bore and stroker kits](https://tboltusa.com/store/z50-88-99-z50-88-99-big-bore-and-stroker-kits-c-68_1056_1057.md) Where a fitment line says "All", it means all years of the model named on that line, not all bikes. ## Description (the store's own text) TBParts Race Cam, 88cc Big Bore kit, and 20mm Carburetor Performance Kit **Key Features:** - Lightweight aluminum cylinder with steel sleeve - Cast in mounts on cylinder for aftermarket skid plates - Oversized cooling fins on cylinder for efficient heat dissipation - TBW0190 52mm piston with rings, pin, & clips - Head gasket kit - Main jet kit - High performance race camshaft aggressive lift and duration without sacrificing low end torque - 20mm Performance carb assembly. Includes: 20mm carb, intake, heatstop, gaskets, mounting hardware/wrench, air filter throttle cable **We recommend purchasing a high volume oil pump kit part number TBW0226** Installation Note: It will save a lot of time and effort if the oil pump is installed while installing the bore kit (requires cylinder removal). 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 purchasing the shop manual for your bike available in our store. The parts are installed in the same manner as the OEM parts. Exceeds OEM Standard equipment **Application:** - Honda Z50 1988-1999 - Honda XR50 All Years - Honda CRF50 All Years **Kit Includes:** - TBW0190 Piston - TBW0206 Gasket - TBW0156 Cylinder - TBW0125 Carb - TBW0263 Intake Manifold - TBW0301 Throttle cable - TBW0398 Air Filter - TBW0189 CamShaft - TBW0294 Jet kit **A Great Upgrade Kit Stock Head!** Not for use with the TB V1 or V2 Race Head. ## Shipping and returns - Flat rate shipping is $8 for parts orders under $75 and free for most parts orders over $75, within the continental 48 states. Heavy items (engines, complete bikes, suspension) are excluded. - Full shipping policy: [Shipping policies](https://tboltusa.com/store/shipping-policies-i-6.md) - Returns: the store's own policy page says how returns, exchanges and cancellations work. Please read it before buying: [Returns, Exchanges and Cancellations](https://tboltusa.com/store/returns-exchanges-and-cancellations-i-11.md) The page begins: "All products returned to T Bolt USA must be reviewed and approved." ## How to buy This item is out of stock, so it cannot go in the cart now (see Stock above). Cart: [Shopping cart](https://tboltusa.com/store/shopping_cart.php) ## Photos - [Photo 1](https://tboltusa.com/store/img/p/396/tbparts-88cc-big-bore-kit-race-cam-and-20mm-carb-kit-for-z50-crf50-xr50-88-prese-1.jpg) ## Support Since 2004, every purchase from TBolt USA includes access to technical support from our staff of experts and our online [Pit Bike Technical Info Database](https://tboltusa.com/store/tbolt-usa-pit-bike-minimoto-technical-info-database-tech-15.md)! We have all necessary support parts on hand. *Most* orders ship same, or next business day, unless otherwise noted above.