The Benefits of Wiseco Forged Pistons vs. Cast Pistons

Fitting a new piston to your machine is a serious commitment, so you want to install one that provides power and reliability. OEM cast pistons are fine, but they can’t touch a forged piston for strength, weight and performance. 

Wiseco has specialized in making forged pistons since 1941, and we put our trust in them when rebuilding our powersports machines. Watch the video above or read on below to find out why we rate Wiseco pistons so highly.

Wiseco Forged Pistons in Dirt Bikes

The stock OEM piston on a dirt bike such as the Honda CRF450R is designed to perform perfectly across a wide range of operations. OEM pistons are more than capable of producing enough speed to give weekend warriors a white-knuckle ride, or churn out plenty of power to give the more experienced rider the high-level performance he or she seeks.

However, competition and professional riders need a little bit more from their machinery. Wiseco forged pistons are built with greater precision and to finer tolerances to withstand more abuse, and deliver an extra performance edge that can make the difference between finishing first or second in a race. For example, the OEM Honda CRF450 piston’s compression ratio is 12.5:1, which is fine for general riding applications. However, with Wiseco pistons you can choose more aggressive compression ratios, such as the 14.5:1 ratio Wiseco Elite series. 

Wiseco pistons can withstand higher compressions because they’re forged stronger, and can cope with the additional power and stress generated from a race-tuned engine. These pistons allow you to run a more aggressive engine, making them more reliable than their OEM counterparts.

Wiseco Forged Pistons in ATVs

OEM cast pistons in quad bikes are also fine for general use, but again, a forged piston delivers better performance. For example, the stock Honda TRX450 cast piston is a tough component, but has its limitations. The Wiseco forged piston, on the other hand, is altogether stronger and lighter, so it will always outperform the cast piston that comes with a TRX450 engine.

How Cast and Forged Pistons Differ

A cast piston is made by pouring molten aluminum into a mold. As the liquid aluminum sloshes around in the mold, the structure of the metal itself becomes a haphazard jumble of particles. Think of cast metal as being like particle board: a disarray of wood chips all glued together that make the finished product strong enough for general use, but not suitable for much else.

A Wiseco piston is forged by taking a solid aluminum billet or puck and pressing it into shape using massive hydraulic pressure. The compression process ensures the structure of the metal itself remains uniform, and therefore much denser and stronger. Think of forged metal like whole wood: the structure is made of thousands of fibers all interlocking and facing the same direction. It’s much stronger than particle board, and can be used in many more applications.

Advantages of Wiseco Forged Pistons

The advantage of a denser, stronger forged piston is that less metal is needed to create it than a cast piston, so Wiseco forged pistons are smaller and lighter than their OEM cast counterparts. 

A lighter piston means less rotational weight, and a smaller piston means less surface area is subject to friction, which means less resistance, heat buildup and wear to the piston and cylinder. Cast pistons are considered complete once they’ve been cast and gone through the finishing process. However, Wiseco pistons are forged, finished and then coated with ArmorPlating and ArmorGlide. These coatings reduce friction with the cylinder bore (for slightly greater crankshaft speeds); prevent piston ring blow-by (for better compression); and protect against combustion chamber detonation (for more aggressive fuel/air mapping), all of which mean more power is produced from the engine.

Choosing the Right Wiseco Piston

If you want to fit a Wiseco piston to your dirt bike or ATV, how do you know which one will be best for your machine and riding needs? If you’re running a high performance engine with a nikasil cylinder that can’t be bored out, you only need to think about the compression ratio you want from your piston. Wiseco offers various compression ratios, and if you increase your piston’s compression ratio, you’ll have to make other changes to your engine. Things like the air-fuel map and the type of fuel you’re using must all be able to handle the higher compression ratio of your Wiseco piston.

If you’re running a motor with a cylinder that can be bored out, thanks to the precision Wiseco forged pistons are manufactured to, you can bore the cylinder to the exact dimension of the piston. For example, if a Wiseco piston says it’s for an 86.5mm bore, you can have a machinist bore your piston to 86.5mm without having to calculate additional tolerances required by less refined pistons that are prone to greater expansion and friction.

Another advantage of choosing Wiseco forged pistons is that each piston comes complete with piston rings, wrist pin and wrist pin circlips all in one box. If you choose a Wiseco piston kit, you get the piston, rings, wrist pin and circlips, plus all the gaskets, seals and O-rings necessary to complete a full top-end rebuild. 

Everything you need is included in Wiseco kits, making them ideal for enhancing, restoring or rebuilding engines that you want performing like brand new or better.