Pop Off Pressure for Kehien

[thelastman2]

I have come across conflicting info for setting the pop off pressure on a 40mm (38?) Kehien carb that is on a 750SS. I just completed a rebuild and had the exhaust ports raised to XI specs. The machinist advised me to go with the next larger jet since I will be running a single carb. I have a Clymer performance manual which states the popoff pressure should be in the 12-14 psi range. I found information on this site which states 24 psi is the recommended pop off pressure. Why conflicting info? I also have found in order to get a reading on the pressure gauge I have to plug both the return line on the carb as well as the pulse line on the pump. Is this a normal characteristic or do I have a bad pump?

[Technical Support]

you should set it to 20psi, 4lbs eigther way is not a big deal. You should have the carb apart when you are checking popoff. Your guage should be placed on the filter side of the seat with the filter removed and the diaphram off.

[hrocker]

Re: Pop Off Pressure for Kehien

what are the porting specs (particularly exhaust port) for the XI? I have and SS750 apart right now and would like to alter the porting.

Or, do you know where I can find the specs.

Thanks