Join Date: Oct 2006
I can't be 100% sure about the 91 head.....I've always stayed 96 and up. You could search and see if the bare head uses the same part number? I know the lower end is different as in different internal parts.
You can see the pipe that leaves the head, that metal one running up from the spark plug area, anything attached to that can be removed all the way back to the carb. Plug the carb hose where it "T"s, one side goes to the petcock and the other to the pollution valve. Buy the kit to block the metal pipe off at the head or leave the pipe there and block the hose. OR, if you can braze or solder well, take that pipe off, remove the "O" ring and then cut it at 1/2" and then seal it up......even JBWeld would work I would say. Put the rubber "O" ring back on and bolt it back down.
Then it's on the the carb and setting it up to run better. Nothing you have done so far has made it worse....just saying.