Millennium M-Spec +5mm Big Bore Cylinder Kit for Polaris 570 (RZR, Ranger, Sportsman)

A worn top end costs you power, burns oil and makes cold starts harder. If you’re tearing it down anyway, a big bore kit puts back more than you lost. The Millennium M-Spec +5mm Big Bore Cylinder Kit for Polaris 570 (RZR, Ranger, Sportsman) (part K292) comes from Millennium Technologies, known for its NSC-plated cylinders and big bore kits.

Shop more in our engine rebuild kits collection.

Why Choose the Millennium M-Spec +5mm Big Bore Cylinder Kit for Polaris 570 (RZR, Ranger, Sportsman)

Key Features

• Complete bolt-on big bore kit for strength, durability and power, per Millennium
• +5.00 mm over stock bore
• High-performance forged piston kit with rings
• Tool steel wrist pins and locks
• Complete gasket kit included
• Made in the USA, per Millennium

Great For

• Top-end rebuilds that add power
• Riders who already run an exhaust and intake
• Dunes, mud and hard trail riding

Specifications

• Brand: Millennium Technologies
• Part number: K292
• Overbore: +5.00 mm
• Type: Complete big bore cylinder kit
• Availability: Backordered; ships when back in stock

Fitment

Listed fitment:

• Polaris RZR 570: 2012–2021
• Polaris Ranger 570: 2014–2021
• Polaris Ranger 800 Crew: 2014–2021 (verify)
• Polaris Sportsman 570: 2014–2021
• Polaris Sportsman 570 X2 EPS: 2015–2021
• Polaris Sportsman Touring 570: 2015–2021
• Polaris ACE 570: 2015–2017

Engine and trim matter on big bore kits. Contact us with your VIN before ordering, and we’ll confirm it’s the right kit.

How to Choose

• Complete kit: Cylinder, forged piston kit and gaskets in one box. Pick this for a new big bore build.
• Replacement cylinder: For an M-Spec kit you already run, if the cylinder is damaged.
• Replacement piston kit: For freshening an M-Spec top end at service time.
• Supporting mods: Bigger displacement needs more fuel. Ask us about fuel tuning before you ride hard.

Installation Tips

1. Use a service manual; this is a top-end engine job.
2. Clean the gasket surfaces and check the head for warping.
3. Check piston-to-wall clearance and ring end gaps before final assembly.
4. Torque all fasteners to spec in the right sequence.
5. Fill with fresh oil and follow the break-in procedure in the kit instructions.
6. Recheck for leaks and change the oil after break-in.

Not comfortable with engine work? A qualified powersports shop can install it.

Care and Maintenance

• Change your oil and filter on schedule, and more often after hard riding.
• Keep your air filter clean; dirt is the fastest way to wear a top end.
• Warm the engine up before riding hard.
• Check compression once a season to track wear.

Related Millennium Products

• Millennium M-Spec +5mm Big Bore Cylinder Kit for Polaris RZR XP 1000 & General 1000
• Millennium M-Spec +5mm Big Bore Cylinder Kit for Polaris RZR XP 900 & Ranger XP 900
• Millennium M-Spec +5mm Big Bore Cylinder Kit for Polaris RZR 800, Ranger 800 & Sportsman 800

Shop More

• UTV & ATV Engine Rebuild Kits
• UTV & ATV Performance Parts
• Polaris RZR Parts

Helpful Guides From the Witchdoctors Blog

• Low ATV/UTV Compression: How to Check Engine Cylinders for Power Loss
• Synthetic vs. Conventional Engine Oil for ATV & UTV

Frequently Asked Questions

Will it fit my machine?

Check the fitment list above. Contact us with your VIN if you’re not sure.

Do I need a tune?

A bigger bore usually needs more fuel. Ask us about fuel tuning options for your machine before you ride hard.

Is it made in the USA?

Millennium says it is.

Can I return it?

Unused parts in original packaging can usually be returned. Contact our customer service team, and we’ll help.

Where to Ride

Test out your new power at one of these off-road parks:

• Brimstone Recreation (Huntsville, Tennessee): about 300 miles of trails
• Sand Mountain Recreation Area (Fallon, Nevada): about 4,800 acres of dunes

Order the Millennium M-Spec +5mm Big Bore Cylinder Kit for Polaris 570 (RZR, Ranger, Sportsman) Today

Add it to your cart, and Witchdoctors will get it moving as soon as it’s back in stock. Questions? Contact our team, and we’ll help.

Shipping

Qualifying Retail orders $159.99 or more will receive free ground shipping. Free Shipping Terms and conditions.

All orders over $500 will require a signature.

Please see International Shipping page for orders shipping outside the US.

See our full Shipping Policy page for further details.

Product Availability

We show real time product availability. These products normally ship the same business day but may ship from one of our warehouses across the country. If an item requires additional processing time you will be notified.

Returns

If your order arrives and it is not right, we will we'll fix it. We promise!

Doesn't fit or just not happy with it? You can return any new, unopened, unused or unaltered item within 30 days of delivery receipt of your item. We will issue a refund to your original payment method.

See our full Return Policy for all of the pertinent details.