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Modern Chassis. Legendary 2-Stroke Power.
Breathing new life into the 2003-2008 KX125 engine, this conversion kit allows you to transplant your powerplant into the superior geometry of the 2016-2018 KX450F or 2017-2019 KX250F aluminum chassis. Designed by Arana Designs, this kit provides the critical components and engineering required to build the ultimate small-bore project bike.
Leveraging advanced 3D scanning and CAD modeling, we have calculated the precise geometry needed to merge these two generations of Kawasaki technology. This kit is designed for the serious builder who wants a factory-level finish and handling performance that far exceeds the stock steel-frame chassis.
Fabrication Overview: This is a builder’s kit that requires aluminum fabrication. The installation process involves cutting the stock lower frame rails, relocating the frame "Y" piece upwards to clear the exhaust port, and welding in the new components. We provide the precision parts; you provide the fabrication skills.
Key Features:
Engineering First: Developed using 3D scanning to ensure perfect sprocket alignment, carburetor angle, and intake geometry.
Mandrel Bent Rails: Includes 6061 aluminum rails, CNC-bent to provide optimal clearance for the expansion chamber while maintaining chassis rigidity.
Hybrid Mounting: Features weld-in lower engine mounts for permanent strength, combined with bolt-in billet head stays for easy maintenance.
Kit Contents:
Mandrel Bent Lower Frame Rails: Pre-formed aluminum tubing ready for fit-up and welding.
Weld-In Engine Mounts: CNC-machined front and lower mounts (requires welding to frame).
Billet Head Stays: Bolt-in design that ties the 2003-2008 engine to the modern frame spar.
Fuel Pump Delete Kit: Includes a billet block-off plate and adapter to convert the EFI tank for gravity-fed premix use.
Stainless Hardware Pack: All necessary high-strength bolts and fasteners for the bolt-on components.
Radiator and Pipe mounting Tabs: All necessary tabs to mount your new conversion radiators and expansion chamber.
Precision ground Swingarm Spacers: Drop-in spacers to properly align your engine in the chassis. Machined from 52100 bearing steel to same specifications as OEM to prevent premature swingarm bearing wear.
Ignition Coil Mount Plate: Bolt-on laser cut plate to hold your OEM KX125 coil in place
Fitment:
Engine: Kawasaki KX125 (2003-2008)
Chassis:
Kawasaki KX450F (2016-2018)
Kawasaki KX250F (2017-2019)
Compatibility
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Customer Reviews
Overall rating: 4.9 / 5 from 58 reviews.
Shipping was fast, the product is great!
When you could still buy the shift forks from Kawasaki they came out of spec :-(
These are in spec and far better quality than Kawi's forks.
They are in the bike and vastly improved the shifting on this KX500 BEAST!!!
Thanks Luke!
Unfortunately, the gas cap got scratched during shipping,
but after a few friendly emails, the problem was resolved perfectly for both sides.
Friendly service, quick solutions, absolutely reliable
Top-notch shop👍
Everything I have received from TSO has been excellent, I was excited to see TSO had the pressure plate because they was the only ones , thanks for amazing products and service
Very well made pipe fits good have not been riding yet so don’t know if it leaks out two stroke oil like the stock one does we will see when it gets cool out for riding
Very quick shipping, and super pleased with the quality of this stator cover! The anodized black blends nicely with the satin black powder coat on my KX500 engine.
Quality parts!!! Very happy with what I received for the money!! Fit and finish is top tier. Also happy to support a company who is helping keep these two strokes alive! I will be back for more parts soon!
Bearings were a perfect fit. A couple of shaft bearings were on back order, which I reicieved shortly after a majority of my orders arrived. Quality of everything is immaculate I would certainly do business with Luke again. I honestly wish I could have purchased the billet cases for my kx500af build after seeing the precision on the covers and head. Highly recommend TSO
Haven't installed these parts yet but the maching and quality looks better than OEM. Looking forward on trying out their other specialized parts offered.
I ordered the case saver for my 98 kx250, the price of the TSO case saver was very close to the same as the original kawasaki one.
The difference is huge, The TSO case saver is made of stainless steel for extra strength and great looks.
Shipping and customer service was very fast and included mounting hardware.
First time I ordered from TSO, but it won't be my last.
Thanks TSO for offering a quality part and great customer service!
So the cylinder head is immaculate and performs perfectly with the decompression valve. Much much easier to start this 500cc 2 stroke. I just wish I the decompression valve was coming off the side instead of straight out the top. Decompression valve creates interference taking out the spark plug when everything is mounted and the bike is together. Purchased a new wrench to remove the spark plug and all is ok. Overall happy 😁