The machinist said that in his opinion it was a bad assembly job by the previous owner/shop that put those piston in bassed only the fact that the vertical cylinder was pristene.

The results of the compression check for the horizontal cylinder was only 60 psi so upon removal of the head I found a damaged piston and cylinder wall. My question now is do I gain much by boreing it out to a 94mm on both, what do I gain and are there other changes required such as a new eprom chip?

I did a compression check on the Paso and found the horizontal cylinder to be low. The bike has Arias high compression piston. Can anybody tell me what I should be getting for compression.

Update:
Found an aftermarket universal adjustable pressure regulator for a reasonable price and modified the mount only slightly to get it to fit, adjusted it to the recommended 3 bar and it seems to be running fine after finishing the tune.
Thanks again for the help.

Yes I read the article after my post, good info, however I am faced with a bad regulator as the amount of fuel coming out of the regulator through the vacuum port is substantial and am searching for an alternative to the oem do you have any suggestions?

Hey people, I recently purchased a gorgeous black 92 907ie that had been sitting for about 5 yrs in a garage. I took her home and flushed all the fluids, cleaned the tank, fuel pump, throttle bodies, and injectors, replaced all the fuel lines, went through the TPS calibration (set to 150 mv), and wh...