Engine Services: Big Bore, Stroker, Porting & Throttle Body Boring

Engine work has been part of what we do since the Rossier Engineering days (1998–2009). We build race engines and custom exhaust for ATVs, UTVs, dirt bikes, snowmobiles and personal watercraft, as well as the KTM 690 / Husqvarna 701 / GasGas 700. Services include:

• Big-bore and stroker kits and engine packages, contact for pricing (for example, a 2003 CR250 built into a CR280)
• Cylinder-head porting
• Throttle-body boring
• Race engines for ATVs such as the Yamaha YFZ450, and ice-racing motors
• Custom engine packages matched to intake, exhaust and tuning

On a Gen 3 KTM 690, a bored stock throttle body and mild porting helped reach 82.83 hp on 91 pump gas with a stock cam, valves and piston.

Every job is quoted individually. Tell us about your project.