Yamaha TTR 250 | Mikuni TM33 | Carburetor Pumper Carb Kit

Achieving high speeds has never been more accessible. These carburetors have long been the preferred choice for enhancing the performance and power of any 250cc or 300cc engine, provided there is sufficient space. They deliver remarkable improvements in throttle response and overall rideability, particularly when installed on your Yamaha TTR250.

The Mikuni carburetors are specifically designed to fit the air box boot and intake manifold rubber flange of your Yamaha TTR250. The original equipment manufacturer (OEM) carburetor measures 100mm in length, while the new TM33 is 93mm long. As illustrated in the accompanying images, the OEM air box boot can be easily adjusted to fit over the new carburetor. To ensure proper clearance, a small amount of material must be removed from the motorcycle’s top frame bracket, and the rear shock fluid reservoir may need to be slightly repositioned by bending its mounting bracket. The kit includes throttle cables and a 1/4 turn quick action throttle, as the Yamaha cables are somewhat short in length. Additionally, the kit provides jets, including a middle-sized main jet, along with one jet each in larger and smaller sizes to facilitate precise tuning during wide-open throttle (WOT) test runs.

Factors such as climate, altitude, and fuel density from various octane levels can influence the final tuning process, as can modifications to the cam, exhaust, and cylinder head porting. Therefore, we highly recommend following the provided tuning instructions to potentially achieve even greater performance than initially observed.

Included in this kit are a TM33 -8012 carburetor, a pair of cables, a quick action throttle, and three main jets for optimal tuning.