Yamaha YZ125 2006-2021 & YZ125X 2006-on Power Kit

Pictures are for display only and you will receive the correct parts to suit your bike.

After more than a decade of building high performance engines for riders all over the world we set our sights on creating the best bolt-on packages using the wealth of knowledge we had built up from all the years of dyno and track testing. These kits are designed from the beginning so that every part works together to achieve maximum results… they are not just a selection of random components pulled off the shelf… instead we design and manufacture the head from scratch to achieve a specific power target, then choose the best pipe to compliment the spread of power we are hoping to achieve, and finally create an ignition curve that works in harmony with the fuel and combustion chamber design to extract maximum performance. All of our TSP Power Kits are extensively dyno and track tested and include notes on powervalve and carb setup. Some kits also feature extras such as a V Force reed cage or a Keihin PWK carby depending on the needs of the individual engine.

This YZ125 kit suits YZ125 06-21, and YZ125X 06-on and includes the following components:

• a 2 piece TSP Billet Head anodised in factory-look bronze
• a TSP CDI unit programmed with 2 different ignition curves, plus a handlebar map switch
• a high quality hand made cone section Scalvini pipe by Scalvini Racing in Italy
• Recommended jetting specifications (supplied with every head or power kit sold)

Please note that YZ125X models will need to update to the standard YZ125 power valve spring to be able to get the same results as a YZ125.

Medium Compression: This design offers a similar compression ratio to the stock head, but with a much better design. Squish clearance is tighter than stock and the design is much more detonation resistant than the stock head. It offers improved power throughout the rev range and makes a great bike even better. It is best suited to high level MX riding or very fast riders who like to rev the engine hard.

High Compression: This design is slightly higher compression than the stock head but still safe for 98 RON pump fuel with appropriate jetting. It offers improved bottom/mid power over the Mid/High design and is best suited to trail riding, offroad racing or MX riders who want max midrange pull. It is also recommended for the YZ125X model and gives very linear, strong power delivery when the standard YZ125 model powervalve spring is used (part number 90501-300A0).

As seen on the TSP graph, the power kit has really great results over the stock form!

We also highly recommend adding a Keihin PWK carby to this bike also! It is not included in the price of this kit but it does make a noticeable difference to performance, especially part throttle response and pull out of corners. The carby can be seen here: Keihin 38MM PWK Carby

Additional information