# TB 146cc Bore kit and YX 140 Head Kit

> 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) > [GPX YX 124 & 140 Parts and Kits](https://tboltusa.com/store/pit-bike-engine-parts-gpx-yx-124-140-parts-and-kits-c-51_29.md) > TB 146cc Bore kit and YX 140 Head Kit
- **Web page:** [this page on tboltusa.com](https://tboltusa.com/store/tb-146cc-bore-kit-and-yx-140-head-kit-p-2028.html)
- **Markdown:** [this page as markdown](https://tboltusa.com/store/tb-146cc-bore-kit-and-yx-140-head-kit-p-2028.md)
- **Generated:** 2026-11-03 19:58 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=2028`

All prices are in US dollars (USD). Shipping and any tax are worked out at checkout.

## Summary

- **Part number:** TBW9066-0492
- **Price:** $279.95 USD
- **Stock:** 2 left.
- **Product id:** 2028
- **Product last changed:** 2026-03-03

## 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 > GPX YX 124 & 140 Parts and Kits](https://tboltusa.com/store/pit-bike-engine-parts-gpx-yx-124-140-parts-and-kits-c-51_29.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)

TB 146cc big bore kit with HC piston
YX 140 head with 27mm intake and 23mm exhaust
Stock YX140 cam included and valves are installed

**Specifications:**

- OD of cylinder skirt is 59mm
- 32T cam sprocket
- Intake port size is 24mm
- Exhaust port size is 33mm
- Intake Valve size is 27mm
- Exhaust Valve size is 23mm

**Application:**

- GPX 125cc
- Pitster 125cc
- Piranha 140cc

**Kit Includes:**

- TBW0601 - Aluminum cylinder 57mm (78mm tall)
- TBW0424 - Head and base gaskets
- TBW0823 - 57mm TB piston with 13mm pin
- TRC-0492 - Cylinder 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

For a person: open [TB 146cc Bore kit and YX 140 Head Kit](https://tboltusa.com/store/tb-146cc-bore-kit-and-yx-140-head-kit-p-2028.html), choose any options, press "Add to Cart", then check out from the cart. Payment is only ever entered by the person, on tboltusa.com's own checkout pages.

For an AI assistant building a cart: `https://tboltusa.com/cart/new/item/2028/qty/1` starts one with this product (the first value of every option, qty 1), `https://tboltusa.com/cart/<cart_code>/add/item/2028/qty/1` adds it to a cart you already started, and `https://tboltusa.com/cart/<cart_code>/zip/<ZIP>` gives the shipping options to a US ZIP code. They answer JSON: give your customer the newest `cart_link`, a public cart link, safe to share.

Or give the person one link that fills their own cart when they open it (a public cart link, safe to share; the first value of every option, qty 1): [Put TB 146cc Bore kit and YX 140 Head Kit in my cart](https://tboltusa.com/cart/open/item/2028/qty/1)

Payment: all major credit cards, PayPal, Apple Pay and Google Pay. Money orders by arrangement.

Cart: [Shopping cart](https://tboltusa.com/store/shopping_cart.php)

## Photos

- [Photo 1](https://tboltusa.com/store/img/p/2028/tb-146cc-bore-kit-and-yx-140-head-kit-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.