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Complete high-performance standard bore cylinder kit engineered to deliver a comprehensive, ready-to-install top-end refresh for high-revving junior two-stroke engines. Features a premium cast aluminum cylinder finished with a durable nickel silicon carbide (NSC) electroplate bore and diamond honed to exact tolerances, paired with matching top-end components to ensure optimal ring seal, reduced friction, and maximum thermal efficiency under aggressive racing conditions.
Specs & Details
Manufacturer Part Number: 422-50012K
Alternative Part Number: Cylinder Works CW50012K
Kit Type: Complete Standard Bore Cylinder and Piston Kit
Bore Size: Standard (39.50 mm)
Material & Construction: Cast aluminum cylinder with nickel silicon carbide plating, matched with high-strength forged or cast piston components
Two-Stroke Vehicle Fitment
Make
Model
Engine Type
Year Range
KTM
50 SX
Two-Stroke Junior Motocross
2009–2021
Husqvarna
TC 50
Two-Stroke Junior Motocross
2017–2021
TSO Garage Note
The ultimate plug-and-play solution for rebuilding a tired or damaged junior mini-bike top end. Sourcing matching components individually adds unnecessary downtime and guesswork; this complete kit bundles the nickel silicon carbide-plated cylinder and matching piston assembly together, ensuring exact factory port geometry, correct clearances, and reliable performance right out of the box for high-strung 50cc racing engines.
Compatibility
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Year
Make
Model
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 😁