Richard's ST2 pages - high-compression pistons

Information on this page last updated 08/17/01.

This modification should increase torque and horsepower by something like 5-10%. Stock compression ratio is 10.2:1 and these pistons are manufactured by Weisco and designed and sold by Fast By Ferracci. They give an 11:1 compression ratio. I have a couple of dyno charts from Ferracci that show the before/after results for two of their customers' bikes. This is a great modification, more power everywhere in the powerband and no drawbacks. I have been running premium pump gas and have had no problems with detonation. There are also 12:1 pistons available but I have yet to see any dyno results from these. According to a couple of folks on the ST2 owner's mailing list these will also work with no detonation on premium pump gas.

I bought these from Ferracci for about $350. Installation also requires an ST2 head gasket kit, which is identical to the 900SS gasket kit and is available from Ferracci or any Ducati dealer for about $40. You will need a piston ring compressor, a torque wrench, and an attachment to fit the cylinder head nuts. For the latter I found that a 3/8 drive 15mm crow's foot and a short extension worked just fine. Try to keep the crow's foot at a 90 degree angle to the torque wrench and the torque readings will not be affected much at all. There are two special wrenches available from Ducati for this, one is a 15mm box end wrench with a socket welded to the middle of it and the other is sort of like a long 15mm box end wrench bent into a c shape with a 3/8 drive on one end. Both are fairly expensive, and so unique to this one task that I ended up trying the crow's foot instead.

I made this change after only a couple thousand miles so did not do any sort of honing of the cylinders. From what I understand, they are Nikasil coated so honing would not do much anyway. On my ST2 the new rings seem to have seated just fine a couple of thousand miles after they were installed and oil consumption is normal. Note that I also did this using Mobil 1 synthetic oil, I do not believe in the stories about rings not seating if synthetic is used, at least not on modern cylinders with a Nikasil coating.

I'm not sure how much installation would cost if you had a shop do it. I did the job my self and it took the better part of a weekend. This included checking the valve adjustment which is very easy to do with the heads off of the engine.

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