Gas guzzler on the interstate

[1976RD400C]

I had my stock 400 on the interstate for about 80 miles yesterday. Indicated speeds 65-80 (I know it reads 5mph high). 4500-5500 rpm. Stock everything, gearing, air box, filter and carbs except a 120 main. Whole trip was 115 miles. 25 mpg and blew through 1/2 tank of oil. Couldn't make the 115 miles without a stop for fuel. It's funny the service manual says they get more than double that for mileage. 

[m in sc]

they were probably rating the mpg at 40 mph or something. they used to do that pretty regular. 35 seems to be about the max i ever saw out of a stock rd.

think thats bad?  a stock kawasaki S2 got 15. FIFTEEN. they actually got better mileage with chambers and tuning. lol. 

[2TFool]

Probably a UK gallon as well :)