DROWsports Honda Grom LS198 4 Valve Big Bore Cylinder Kit

DROWsports x LimitSport NEW 66mm Big Bore Cylinder Kit for the Honda Grom/MSX125 and Honda Monkey was designed specifically for the KOSO Grom 4v Head. We wanted to offer an affordable upgrade from our LS181 63mm cylinder. Taking features from the 181cc piston like; lightweight piston, strutted design piston, radius edge dome etc and applied it to our kit.  We love everything about our 63mm LS181 but we wanted a little even more displacement. 

Piston Features

• 66mm Forged Piston (198cc)
• The 4 valve piston comes forged, which is one of the best options for performance and reliability. Forged pistons compared to cast pistons are much stronger and more reliable due to their manufacturing process. The forging process gives it stronger structural integrity over cast pistons. Forged has a smooth and consistent grain structure due to the heat and pressing process. 
• Lightweight
• (Not all forged pistons are the same) Compared to the other Grom 4 valve pistons, our 66mm piston only is probably one of the lightest available. 
• CNC Machined
• Once these are finished being forged, they are precision CNC machined. Machining it versus pouring metal into a cast allows the piston to have higher tolerances. This is a more expensive process but provides the highest performance option available. For this reason alone, it allows the best seal with the piston rings inside the cylinder.
• Strutted Piston Skirt
• The piston skirt utilizes a strutted design over a full round design. Having a strutted design not only reduces the weight but provides key points that can be machined to increase overall piston strength where the rods connect. This characteristic shaves off undesired weight and can be designed to help keep piston structure sturdy. This also helps with less friction due to reduced amounts of material against the sidewall of the cylinder.
• Machined Radius Edge
• Each edge on the crown has been machined with a radius edge to eliminate possible hot spots which yield better flame travel. This will prevent damage to the piston in one particular area.
• Wrist Pin Broaches & Double Pin Oiler
• Every performance piston requires proper lubrication which is commonly forgotten about once it comes down to the actual piston. Our design includes specialized oiler grooves inside the wrist pin location. The oil enters the grooves through the broached machined ports. The broaches are machined precisely to allow the proper amount of oil in for lubrication. It helps with preventing piston pin wear and seizing by keeping the entire pin oiled.
• Frictionless Coating
• Each piston comes with a specialized coating on the skirt edges that reduces piston slap and is made to be frictionless. This allows the piston to move even more freely in the cylinder. This coating reduces scuffing and provides backup lubrication and works well with engines with longer rods and Nickasil cylinders.
• V-Shaped Accumulator Groove
• The V-Shaped groove that sits between the first and second ring was machined with the intentional purpose of relieving the top ring by adding volume between them. What it does is accumulates residual gasses from the combustion chamber. This will help prevent premature wear on the rings and provides an overall improved ring seal.

Cylinder Features

• Cylinder Performance
• DROWsports 66mm Big Bore Cylinders are all machined and specially designed for performance and reliability. Since these cylinders are paired with such a high-performance cylinder and cylinder head, we had to make sure it lasts!  This cylinder is similar to the KOSO 170cc cylinder except we've expanded on it to create an even more durable product.
• Ceramic-Coated Cylinder
• The ceramic cylinder was a clear choice for heat dissipation and reliability. This type of cylinder creates a stronger exterior surface while efficiently alleviating the heat. 
• Electroplated Nikasil Walls
• We've combined this with another unique coating for the ultimate cylinder performance. The inside wall is electroplated with Nikasil. Silicon Carbide is an extremely hard ceramic compound that is dissolved and electroplated onto the cylinder walls using Nickel. This process makes the cylinder walls even more durable and allows the engine tolerances to be much tighter. Tighter tolerances mean better performance capabilities.

Includes:

• 66mm Forged Piston for Grom KOSO 4Valve Head
• 66mm Ceramic Cylinder*
• Piston Rings
• 15mm Piston Pin*
• Piston Clips
• Head Gasket
• Base Gasket

*this is not a drop in a big bore kit, will require machine work.