These Crank Shafts can be used with OEM Pistons and Rods " original length" but when using Original or High Performance Pistons "original leanth" a 1.8mm or 2mmm Head gasket will be required.
85mm vs 87mm stroke
The genuine OE crank shaft has a stroke of 85mm. If you would like to stay within OE specs, this option is for you.
Maruha has also developed a crankshaft with a stroke of 43.5mm x 2 = 87mm. With this option, you will increase engine displacement. This will give you more torque and power.
Again, both options are lighter than OE, so you can expect a livelier engine response regardless of which crank you choose.
How to use 87mm stroke crankshaft
The 87mm stroke has a 1mm larger turning radius than OE. When combined with OE pistons and rods, it will stick out 1mm more. In this case, a 1mm thicker head gasket will be required to compensate for the difference.
If you have plans for or have already built an oversized piston and rods setup, all that is required is to match up with a suitable head gasket thickness (also available from Maruha). This is by far the most cost effective way to use this new 87mm crankshaft.
Using the 87mm Crank will raise the compression and CC of your engine. Please refer to engine Spec sheet in photos.