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I had the "experimental" head mod done (Squish Band and Compression raise for pump gas). I get my cylinder back from Poweseal on Wed or Thur so when I get it all together with the new Wiseco forged piston does anyone know how much more psi I should be getting over the stock setup?

That will be hard to say. All cylinders are a touch different in porting due to castings. That will have an effect on compression. Also you are going from a tired motor to a completely fresh motor with a cut head. Your compression SHOULD be alot better than it was before. As for how much the head alone adds, noticable, not drastic, but noticable

The manual says a max of 150 psi. If I get that I will be stoked since I was down to 118 for the last month I rode it. The original coating had given up long ago but I was having so much fun riding I didn't have the heart (or money) to do it any earlier than now.

I replaced the piston on mine because it was 12 years old and I felt bad for it and I already had it apart. I checked the compression before I tore the engine apart and it had 150 PSI. I put it all back together and after a few rides with the new piston I had about 143 PSI. Should have left well enough alone I guess.

Not really related to your question, mine is a 200 with no head mod but just thought I would throw that out there.

Obviously the specs that Ron uses are his own years of research and I wouldn't expect it to be all over the forums.

Quick trivia .... Our 200 with fresh Wiseco and .015 off the head will pump 170 psi warm.

I'd suggest to send the head to RB vs. just have a local machine shop wack off a guessed amount.

Compression will often be higher on a worn engine because of the carbon deposits on top of the piston. They actually RAISE the compression.

[quote="rbates9"]I replaced the piston on mine because it was 12 years old and I felt bad for it and I already had it apart. I checked the compression before I tore the engine apart and it had 150 PSI. I put it all back together and after a few rides with the new piston I had about 143 PSI. Should have left well enough alone I guess.

5% difference is not big deal , one less kick , a different engine temperature , and the time idling or not before
shutting off will easily give you that difference. Nothin to worry about .

C George wrote:

rbates9 wrote:I replaced the piston on mine because it was 12 years old and I felt bad for it and I already had it apart. I checked the compression before I tore the engine apart and it had 150 PSI. I put it all back together and after a few rides with the new piston I had about 143 PSI. Should have left well enough alone I guess.

5% difference is not big deal , one less kick , a different engine temperature , and the time idling or not before
shutting off will easily give you that difference. Nothin to worry about .

Never lost a seconds sleep over it. Just one of those kind of things. Try to make things better and it ends up worse. It will be due for a replate before long anyway so after that I can have a little concern for it.