BIG BORE / STROKER KITS Our Big Bore/Stroker crank kits are winning races and championships all over the world. These kits improve the horsepower, mid-range and overall powerband. Our test riders and pro racers report increased power that's easier to control, allowing them to get on the power earlier when exiting corners. This increases straightaway speed and lowers lap times, while reducing rider fatigue. We offer billet stroker cranks, modified OEM stroker cranks, big bore cylinders and modifications, as well as complete kits for several models. Ways to increase engine size: Big Bore kits Advantages: Relatively easy Changing just the cylinder and piston is easier than splitting the cases and installing a stroker crankshaft. Cheaper than a crank, but not by much. Disadvantages: Head is not designed for that diameter cylinder. Too large bore results in incomplete combustion Too large bore reduces cooling jacket. Larger piston adds stress to rod and crank. Excessive vibration from heavier piston. Still need to remove crank to rebalance for heavier piston assembly. But if you do all that work, you might as well use a stroker crank. Stroker Cranks Advantages: Stock Piston sizes are cheaper to replace and easier to get. More torque Better traction Easier to control Complete combustion – using head designed for this bore. Longer stroke breathes “deeper” while valves are open. Generally, better power than bore kits Disadvantages: If done poorly, can result in vibration Very large stroke may require case modifications Somewhat more expensive than big-bore kits. Few companies can do it properly. Big Bore / Stroker Crank Combinations Advantages: Properly done, you get the best power Overcome design problems with OEM design Tailor power/reliability to application Overcomes limitations of just bore or just stroke Tailored bore/stroke ratio Adding stoke allows larger bore Disadvantages: Costs more Non-drop-in kits can be more work to install. DESIGNED FOR THE EXPERIENCED ENGINE BUILDER Please note: We design these kits for experienced race engine builders. They do not contain complete "how-to" step-by-step instructions on building an engine. When the installation is complete, tuning will be required, including jetting, valve timing, ignition timing and other issues. Sometimes the engine manufacturer will make slight changes to an engine that could cause interference with our crank, rod or other part. The engine builder should check all clearances, and modify the cases to provide proper clearance. Please keep in mind that we cannot always know if this will be necessary with your cases, and you should take this into account. If you don't know how to build and properly tune a race engine, including the installation of a crankshaft, we suggest you contact a professional engine builder or your dealer. This is not rocket science, but you do need to realize that improper installation or tuning can ruin your engine. CONTACT YOUR LOCAL DEALER OR CALL US DIRECTLY FOR PRICING @ 727.797.2468   BIG BORE / STROKER KITS AVAILABLE FOR: HONDA: CRF-250R: 297cc CRF-450R: 450cc LR, 450cc DTH, 498cc, 525cc TRX-450R '04/ '05: 513cc, 531cc, 545cc, 564cc, NEMESIS 600cc NEW ! TRX-450R '06: 498cc, 526cc, 546cc SUZUKI: HAYABUSA: MEIMU 1402cc, RONIN 1485cc, SHOGUN 1525cc SAVE BIG $$$ ON KIT PACKAGE ! SV- 650: 629cc, 697cc, 754cc YAMAHA: YZ-450F '05: 513cc, 534cc YFZ-450: 498cc, 513cc CLAWHAMMER, 513cc SCREAMER, 534cc, MINOTAUR 565CC NEW ! RAPTOR/ RHINO 660: 719cc, 762cc RAPTOR 700 : 779CC NEW ! COMING SOON 825CC KIT ! YFZ-450: MANTIS POLARIS: PREDATOR 500: 600cc, 636cc HARLEY DAVIDSON: V-ROD: 1430cc, 1485cc, 1550cc CNC Ported Twin Cam H. D. Heads ROTAX/ BMW: DS-650: 691cc   BILLET STROKER CRANKS AVAILABLE FOR TWIN & FOUR CYLINDER : These displacement figures are calculated with standard bores. Oversize pistons will result in higher displacement SUZUKI: HAYABUSA: 1402cc (+5mm), 1485cc (+9mm), 1525cc (+11mm) GS-1100: 1081cc (+.4mm), 1108cc (+2mm), 1178cc (+6.34mm) SV-650: 665cc (+3.4mm), 685cc (+5.4mm) KAWASAKI: ZX-14: 1441cc*** (+4mm) HARLEY DAVIDSON: V-ROD: 1225cc*** (+6mm), 1272cc*** (+9mm), 1327cc*** (+12.5mm)   - stroker Knife® Connecting Rods available for all billet cranks! - * weld-up stroker ** requires special stroker piston ( sold separately) *** requires special stroker piston ( sold separately)       HONDA KITS (example)     YAMAHA KITS (example)   V-ROD KIT HAYABUSA "RONIN" 1485cc KIT (example)