Sale

Engines and Components› Oiling Systems

TB Parts

Race Head V2 & 146cc Big Bore Kit

$599.99 $599.95 Save $0.04

SKU: TBW9127

In Stock
In Stock
Ships by Sep 12
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The TB Parts Race Head V2 & 146cc Big Bore Kit is a performance upgrade designed for China 120cc and 125cc engines. It features roller rocker arms, larger intake and exhaust valves, and a high-compression piston.
Show original supplier description
The TB Parts Race Head V2 & 146cc Big Bore Kit is a comprehensive performance upgrade designed to enhance engines from China's 120cc and 125cc series. This kit is engineered to provide a significant boost in power and performance, featuring key components like roller rocker arms, which are similar to those found in the KLX110 V2 head. This kit includes a 57mm all-aluminum cylinder with a ceramic-plated bore, paired with a matching 57mm high-compression piston, rings, pin, and clips. It also incorporates larger valves, with a 28.5mm intake valve and a 23.5mm exhaust valve, both featuring a 5mm stem. The exhaust port measures 23mm, and the cylinder skirt has an outer diameter of 59mm. A high-performance race camshaft specifically for the Race Head and a head gasket kit are also included. The application for this kit is China 120cc and 125cc engines that utilize a 14mm wrist pin. The kit comes complete with all necessary hardware, including the TBW0751 V2 Race head, TBW0821 V2 Head bolt kit, TBW0752 Cam, TBW0754 V2 Head cover set, TBW0414 Cam sprocket, TBW0824 Piston, TBW0862 Top end gasket set, and TBW1069 Cylinder.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

Fitment Guaranteed

Don’t gamble
on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandTB Parts
Part NumberTBW9127
CategoryEngines and Components

We’re here — turning wrenches, just like you.

Call us, follow along, or come say hi.

(760) 282-4645 Instagram Google

Buy with Confidence

Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

View Full Return Policy

Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

View Full Shipping Policy