Two Stroke Performance Oversized Powervalve Cover

What it is

• Oversized powervalve cover with more volume than stock.

Two Stroke Performance is a main player in engine mods for two-strokes. They cover the range, offering kits for carbureted bikes, TPi bikes, and now the latest and greatest TBi bikes. The Australian company offers an array of products for two-strokes, and South Bay Moto Performance, based out of Northern California, is one of the biggest distributors here in the United States and helped set us up with TSP’s products. 

The Oversized Powervalve Cover is as much of a performance part as it is a bling part. Working on all 250/300cc TBi models from the Austrian group, the cover is designed to increase torque and add power at lower RPMs, primarily in the 3000-5000 RPM range. If you want to read more about the science behind it, click HERE. The cover retails for $120.00, is available in a magnesium cover resembling that of a works part, and can be purchased in the US at SBMotoPerformance.com.

How it works

• Increased torque.
• Smoother transition into the mid-range.
• Simple install.

Installation of the TSP Oversized Powervalve Cover is pretty straight forward and requires no special tools. Removing the pipe and unbolting the right side radiator to allow it to move out of the way is all that’s needed and was done in less than 10 minutes in the field. 

The gains on the bike are slight but noticeable. Riding with the cover, you feel there is added torque and low end power, helping make the power more friendly and rideable in all terrains. In tighter terrain, the 300cc TBi engine has more pickup and isn’t quite as “lazy” or slow to build the RPMs when lugging the bike in tall gears. Something that was tough to race with when the bike was completely stock is it was slow to build through the lower RPMs, but would surge into the mid-range and become a handful in rocky, technical terrain - especially when we’d get tired.

Likewise, taking the bike on a MX track or faster GP style riding, it fills in the dip in the power down low and makes it a smoother transition into the mid-range. That transition is fairly abrupt when you’re hard on the throttle and can be intimidating and hard to ride at times, but the PV cover helps smoothen it out and the power delivery is more linear. 

TSP’s Oversized Powervalve Cover isn’t going to knock your socks off in gains and feel like a completely new bike. However, there are gains to be felt and to us, it fine tunes the power delivery and makes the bike more rideable in every terrain. We didn’t find ourselves wanting to put the stock cover on in any scenario whether we were riding in the desert, on the trails, or at the motocross track and it’s rare that we test a product that we can’t find any negative performance traits.