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Cylinder Works Big Bore Cylinder Kit
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Cylinder Works Big Bore Cylinder Kit 478cc

Fits: 2009 YAMAHA YFZ450R
Part# 1296750026

Our price: $369.99

MSRP: $649.95 - You save $279.96 (43% off)

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4 In-Stock

  • "Customer service is priority #1 at Rocky Mountain ATV/MC. We value our customers and strive to be the best shopping experience- when you buy from us, you are buying lifetime service."

    -Dan Thomas, CEO and Founder

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    We take pride in offering no hassle returns. In the event of a return, please call, email or chat with us to receive a solution to the problem. For apparel that doesn't fit quite right, Click here to see our Fit Guaranteed Program.

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    We will stand behind all products we sell with regards to manufacturing defects in workmanship and material. Most products are limited to the manufacturer's warranty. However, we will do everything in our power to take care of the problem.

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  • Cylinders are Nickel Silicon Carbide plated for long life and honed to exact size for easy piston installation.
  • Designed for easy bolt on installation, with no machine work to your engine or cases.
  • Kit comes complete with cylinder, piston kit, and gaskets.
  • Replacement piston kits and gaskets available.

Cylinder Works Big Bore Cylinder Kit Reviews

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1 of 1 people found this review helpful.

Catastrophic Failure

Comments On May 12, 2015:Bought this kit, install went great! Installed this and hotcams at same time. Broke in cams and cylinder as per specs. Took out for first ride and changed oil after, FOUND BROKEN WRISTPIN CIRCLIP IN OIL. Called company, they overnighted part without hesitation. Found other half in engine, removed it with magnet. Installed new ones, bike ran like a dream. 2 months in, let clutch out of a turn and the bike died on the spot with a small pop noise. Broke down engine AGAIN and found the wristpin slide out of place due to another failed circlip, the connecting rod threw the piston up into the head bending my valves and bent the connecting rod while scoring my cylinder wall at the same time. 2,000 in damage thank you

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0 of 1 people found this review helpful.

365cc for KTM 350sxf...buyer beware

Comments On Nov 03, 2014:Cylinder kit goes together nicely, but Cylinder Works gave no support after the installation of this kit. The kit obviously changes the fuel needed, which will require a ECU software change, they offer zero support except a jpeg of suggested settings.

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3 of 3 people found this review helpful.

Awesome kit

Comments On Mar 27, 2013:The cylinder works kit is a very reliable upgrade over stock. Comes with everything necessary to install it. There's no replacement for displacement!

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2 of 2 people found this review helpful.

wow!

Comments On Mar 14, 2013:with hot cams and porting job, it is a HUGE difference... reached 42.39hp on my kfx400, very happy!

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0 of 1 people found this review helpful.

Easy to install

Comments On Jan 03, 2013:The kit was pretty easy to install, It sounds good idling, I havent broken it in yet.

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2 of 2 people found this review helpful.

Much more than I expected!!

Comments On Dec 03, 2012:Crazy power, I usually ride 7 days out of the week. 3 to 8 hours a day so far my new big bore kit is holding up like a champ.

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1 of 1 people found this review helpful.

Crazy Power

Comments On Aug 19, 2012:Installed easy and was there in a snap.

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2 of 2 people found this review helpful.

awesome

Comments On May 10, 2012:my husband locked up the motor on his quad and well needless to say a new engine is costly and a used one for the prices we could find wasnt very practical, he wanted to make sure he knew what was in his engine and what had been done to it, so we went the rebuilding road and this kit made things alot easier. We didnt have to find someone to bore out his motor wich where we live is kinda hard to do. so he got more power without cleaning out the bank account!

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2 of 7 people found this review helpful.

RM are just fantastic

Comments On Feb 27, 2012:Fitted like a glove and power is amazing

Additional Comments On Feb 27, 2012:Valerie has been so much help in the ordering and also shipping, I live in Saudi but the average delivery from RM to my home is just 4 days!!! What moere can you ask for these guys are just excellent and I will continue using them and also recommending them to everyone who needs a supplier of this equipment. Thank you RM

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Instructional

How to rebuild the top end on a motorcycle or atv (Part 1)

How to rebuild the top end on a motorcycle or atv (Part 2)

Product Info

Cylinder Works

Cylinder Works Big Bore Cylinder Kit

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