Small package packs a big punch

The new machine is based around the YZ125, but features increased power across the rev range and has been thoroughly tested to ensure a high level of reliability. The combination of a powerful 144cc engine mated to six speed gearbox fitted into a lightweight YZ125 chassis is sure to be a serious contender, not only in the Junior up to 150cc two stroke class but also MX/SX Lites and Class 1 off road competition where two strokes up to 200cc compete. And it is guaranteed to offer a high level of excitement to thrill seeking dirt bike riders whose main goal is fun.
The YZ144 has been developed in-house by Yamaha Racing Development (YRD) and features modifications to crankcase, cylinder and head as well as custom made piston and ring to produce a bore and stroke of 58mm x 54.5mm (= 143.9cc).
In order to aid and promote maintenance, each YZ144 is fitted with an hour meter, servicing intervals are as per YZ125 recommended intervals. This is not a backyard bolt-on kit and due to the amount of machining work involved, there is no plan to offer the parts as a kit.
The following modifications have been made to the standard YZ125:
_ Modified crankcase set
_ Modified cylinder/cylinder head
_ Modified L+R power valves
_ 58mm custom made piston
_ Custom made piston ring
_ Hour meter
_ Graphics set (front guard, rear guard, L+R radiator shroud)
_ Carburettor jets

All other specifications are as per YZ125, it even sports the standard YZ125 exhaust system. Dyno tests reveal a healthy increase in power across the entire rev range. Owners wishing to increase power further will have other options available.
For example, Cisco's Race Tuning has several power up levels available that include:
_ Custom ported cylinder
_ Specific 144cc exhaust system developed by HGS
_ Crankshaft modifications (1mm off set crank pin) that will provide a further capacity increase to 149.2cc (class limit is 150cc).
_ VHM 144 cylinder head
_ V Force reed valve assemblies
_ HPI programmable ignition units

The YZ144 is now available in limited numbers from your Yamaha dealer, priced at $9,599.