[sk66]

Just got the bike back on the road..'99 900SSie, Had it apart over the winter for a thorough going over; in the process I ported the heads (light job) and put in high compression pistons....First ride today and I scared myself! First gear power wheelie surprised me...wasn't even trying..just grabbed a hand full of throttle (not even all of it) and the front end was airborne!
And I was worried it might not run well....It's a whole new bike now!

 

[sk66]

Where did you get the high compression pistons? how much did they cost? I put hayabusa pistons in my SV650s for the higher compression and it made a big difference.

FBF sells them and so does BCM. Mine are 11something:1 and runs fine on pump gas and the DP ECU that came with the exhaust. I have a Power Commander I bought thinking I might need it for the HC setup....I'll probably wind up selling it.

 

[sk66]

I bought my 944 kit from BCM which included rebored and coated cylinders with the exchange of my old ones. I think it was around a $1000 for the pistons and cylinders. Before that I had just the stock displacement, high comp kit. There is a slight difference in power with the added 40 cc.

Also, its very important that you retard the timing a bit with high comp pistons. I put on about 25,000 miles and ended up burning both pistons during a track day before I went with the 944 kit. Detonation occures with the high compression pistons in the 2V motor cause the motor doesnt flow as well as the 4V ones. Retarding the timing reduces detonation and will prolong the life of the pistions.

Mike

Mine's just 92mm. I haven't retarded the timing...I've had no detonation either high RPM or lugging the motor and a check of the plugs looks good. I did port the intake so it certainly flows more. Plus open airbox/exhaust......