Ran across this and thought it was interesting.
http://global.yamaha-motor.com/jp/showroom/cp/library/yamaha_news_eng/pdf/index/192_YamahaNews_E_1982.pdf
I take it your not riding with a passenger on the back either? You could weigh the trunk and add 20 pounds which I believe was the max load for the trunk on a first gen that would give you a reasonable idea.
I would not feel comfortable with more than 40 or 50 pounds, 10 gallons of gas would weigh 60 pounds plus the weight of the tank but this is only my personal opinion hopefully someone will have the actual numbers for you.
Not a big deal to change it is just little time consuming, here is a previous thread on the subject.
http://www.venturerider.org/forum/showthread.php?100069-2nd-Gen-Air-Filter-clean-and-or-replace&highlight=air+filter
Don to echo what has already been said THANKS!! for all you do.
This is not a total loss folks don't have to look at pictures of my ugly mug in old post now.
I removed my trunk and and relocated the CB to the left saddle bag and made a bracket that bolted on to the license plate bracket for the antennas. I did not have the removable backrest but I did replace the rear fender with a tour deluxe one to solo it out. The passenger Intercom connection is under the passenger seat so all you need to do is add an extension to it to keep the passenger capabilities.
I guess it must be my Appalachian Hillbilly education however I always thought a question was interrogative in nature and followed by a mark of punctuation at the conclusion of the sentence to indicate its interrogative nature.