# TBParts - 170cc to 184cc Bore Kit and Nibbi 28mm Carb Kit for the YX/GPX/Zongshen engines > 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) > [Pit Bike Engine Parts](https://tboltusa.com/store/pit-bike-engine-parts-c-51.md) > [Big Bore and Stroker Kits](https://tboltusa.com/store/pit-bike-engine-parts-big-bore-and-stroker-kits-c-51_24.md) > TBParts - 170cc to 184cc Bore Kit and Nibbi 28mm Carb Kit for the YX/GPX/Zongshen engines - **Web page:** [this page on tboltusa.com](https://tboltusa.com/store/tbparts-170cc-to-184cc-bore-kit-and-nibbi-28mm-carb-kit-for-the-yxgpxzongshen-engines-p-2289.html) - **Markdown:** [this page as markdown](https://tboltusa.com/store/tbparts-170cc-to-184cc-bore-kit-and-nibbi-28mm-carb-kit-for-the-yxgpxzongshen-engines-p-2289.md) - **Generated:** 2026-11-04 16:01 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=2289` All prices are in US dollars (USD). Shipping and any tax are worked out at checkout. ## Summary - **Part number:** TBW9041 - **Price:** $379.99 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=2289&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 5 of 5](https://tboltusa.com/store/reviews/tbparts-170cc-to-184cc-bore-kit-and-nibbi-28mm-carb-kit-for-the-yxgpxzongshen-engines-pr-2289.html) - **Product id:** 2289 - **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. - [Pit Bike Engine Parts > Big Bore and Stroker Kits](https://tboltusa.com/store/pit-bike-engine-parts-big-bore-and-stroker-kits-c-51_24.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) **170cc to 184cc Big Bore Kit and 28mm Carburetor Performance Kit** If looking for easy bolt on power for the YX/GPX/Zongchen engines, this big bore and carb kit is it! Works great with your stock head or our new V2 Race Head. The kit includes an all aluminum ceramic plated 64mm cylinder (with skirt) which will increase your engine displacement and power. This cylinder is lighter than a steel sleeved aluminum cylinder, reduces friction (increasing power), improves sealing, and provides better heat transfer (runs and cools down quicker). We top off the bore kit with a 28mm performance carb kit that is easy to tune and works much better with this setup than your stock Chinese 26mm carb. Additionally, our head gasket kit also 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. The new bore kit consists of high quality parts and requires no machining to the cases \- bolt on and go! This kit is only for the YX/GPX/Zongchen 150cc to 160cc engines with a a KLX110 type topend. The increase in displacement will depend on your stock engine size. With this kit: - A stock 150cc engine will increase to 170cc - A stock 155cc engine will increase to 177cc - A stock 160cc engine will increase to 184cc **Key Features:** - All aluminum ceramic plated 64mm cylinder with skirt - We increased the skirt height and size on the lightweight high compression 64mm piston with rings, pin, & clips to increase reliability and service life (picture is not updated yet showing piston change) - Head gasket kit - includes the cylinder head o-ring set and an exhaust gasket. - Nibbi 28mm Performance Carb Main jets #112, #108, #105 (Stock is #115) Pilot jet #35 (Stock is #40) - Rear Facing Intake Kit - not forward facing like the KLX110 style (picture is not updated yet showing intake change) - Jet kit for varying conditions and exhausts **Recommended:** - Sta-bil fuel stabilizer - W-57-1129 - Uni filter oil spray - W-82-1000 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. **Kit Includes:** - TBW1250 - Cylinder - TBW0503 - Top end gasket kit - TBW0590 - Piston - TBW0301 - Throttle cable - TBW0556 - Intake kit - TBW0491 - Air filter - TBW1655 - Carb ## 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/2289/tbparts-170cc-to-184cc-bore-kit-and-nibbi-28mm-carb-kit-for-the-yxgpxzongshen-en-1.png) ## 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.