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millenium technologies

MXA WRENCH TECH: THE INS AND OUTS OF BIG-BORE ENGINES

Big-bore kits are available from Cylinder Works, Wiseco, CP, L.A. Sleeve, Millennium, Thumper Racing, KTM, GYTR and Athena. This bike is a KX250F turned into a KX269 by Cylinder Works. When you increase the cylinder’s bore you increase the surface area on top of the piston. This spreads the fuel/air mixtures workload and produces more power without taxing the force of combustion. Even with standard cranking pressure you gain better performance because of the extra size of the combusted explosion. Conver…

WE RIDE THUMPER RACING’S BIG-BORE YAMAHA YZ310F

The YZ310F wasn?t built for a chassis test. MXA left the suspension stock. The motor, on the other hand, was a three-grand endeavor, not including the Hinson clutch and titanium FMF exhaust. A quick look at the specifications of Thumper Racing ‘s Yamaha YZ310F makes it obvious that this isn?t your standard big-bore engine kit. Oh, don?t get us wrong, it starts out like all big-bore engine kits?with a desire to close the power gap between a 250cc four-stroke and its 450cc big brother. The hope of every b…

WE RIDE MILLENNIUM TECHNOLOGIES’ HONDA CRF264 BIG BORE

If you have a carbureted CRF250 you are out of luck for an effective big-bore. The 2010 and 2011 CRF250s have thicker cylinder liners that offer more than enough room to go bigger. As a rule, the MXA wrecking crew keeps our test bikes in stock trim. Even though we have access to every hop-up part in the world, we need to keep our bikes as stock as possible to ensure a fair platform for testing individual aftermarket products and different settings throughout the year. When we test major modifications, w…

THE 20-INCH TIRE REVOLUTION

Why are so many of the factory riders testing 20-inch front tires? Are they guinea pigs? What are the advantages and disadvantages of the new tire size? Is the 20-inch actually smaller than a 21-inch tire? Are consumers going to have to dig into their pockets to pony up for a 20-incher next year? What’s all the hype about?