Motorcycle Repair: 1978 CT-90 Vapor lock?, fuel tubes, jet size

Question
Someone wrote a similar question, but in reviewing 105 pages , I could not find it. After riding a few miles in 90 to 105 degrees, it wants to stutter and usually dies at a stop sign. It will usually start in a few minutes, sometimes with choke. One of you experts suggested installing a new fuel cap(which I have done, and it helped some) and changing a jet size, which is the part, I need to know about. Any other suggestions would be very helpful. Thank you for your time.

Answer
Buck,This may not fix the problem but try it. Check the fuel petcock on the bottom of the tank. Due to the age of the bike there may be some rust or debris plugging the fuel tubes in the bottom of the tank.When you replaced the cap it may have helped some because of the rust in the vent passage. Drain the tank and remove the valve and take it apart and clean it out.Some of these units still have a brass screen in there and it corrodes over time restricting the fuel flow.