what does running regular gas in a leadran vehicle do? would a 77 xr75 have been in the lead days?


Lead free gas came on the scene around 1974 and cat converters in earnest in 1975. You should see no immediate consequence from switching back and forth from leaded to unleaded. The word early on was that lead free extended spark plug and exhaust system life. BMW motorcycles were a little late with converting to lead free valve seats but 77 Honda should be OK.