Please select make, model and yearBig Bore Kits
Every rider craves more power from their dirt bike, more torque to pull from. Modifying your top end with an aftermarket big bore kit can be a fairly easy way to deliver the power that you’re after by increasing torque and horsepower to give you noticeable power gains through all ranges.
Aftermarket big bore kits include larger pistons and cylinders which typically increase the engine size by around 3 mm – and it only makes sense that the larger the engine, the more power you’ll get. The cylinders look nearly identical to stock and usually include everything you’ll need, such as:
These kits are made for easy installation and include all the parts you will need to completely rebuild your top end. If you’re up to the task of doing the mechanics, we’ve got a part one and part two instructional video series to show you how to replace the top end on your dirt bike. Make sure you have all the tools you’ll need as well as a service manual and we’ll do our best to guide you through the installation.
Leave your competition in the dust or just impress your buddies with your new-found power and performance when you upgrade your top end with a big bore cylinder kit by Cylinder Works from Rocky Mountain ATV/MC today!
rob in AR
Made my 2014 sxf 350 pull nice. Id give it a 5 but the only reason i didnt is because it really works much better with a jdjetting tuner of something similiar to really make it shine! Nice power at a lower rpm and "lofts" the front wheel easier now. Nothing negative ro say about thw kit whatsoever! Was going to get a 450 but was cheaper to try this and glad i did! Still not thw torque of a 450 on bottom but pulls great and does not sign off early....just keeps pulling.Read All Reviews
David in ND
Although this, and everything else that is GYTR, is ridiculously expensive, it fits well, and seems to work well so far. Straight bolt on, with everything included. Only one ride so far, so can't really say if it's durable, but seems to give a little more snort, if only between my ears.Read All Reviews