What indicators should one look for when examing a ported motor?

Will a compression check give an indication to the general health of the engine?

If so what should the compression numbers be?

Do the plugs of a ported engine foul out sooner than a non port?

 

See how it sounds at idle. Generally speaking, the lumpier the idle, the bigger/more extreme the ports. Also, see what kind of vacuum it pulls (on the boost gauge) at idle. Be sure to note the idle rpm as well.

Yes, a compression check will tell you a lot. In kg/cm^2 (where one = 14.2 psi) 8 is very good, 7 is about average, and 6 is worn. anything below 6 and you will be looking at a motor sooner rather than later. You will get three readings per rotor, ideally they will have a small +/-.

I wouldnt worry about fouling out the plugs. It's a high performance rotary

 

thanks for the response

Judging form the compression numbers you stated (same as stock), the porting does not affect compression.

I have heard that on a stock motor the lower the vacuum, the worse the engine is.

Is there a vacuum reading that would indicate a worn or engine?

If so, what would that be for a a mild port, aggressive port and a bridge port at 900rpms?