Poor fuel economy.

Finally got my 78 kz659sr on the highway but I'm only getting 180km out of a tank of gas. Power seems good through the rpm range, and can't see any fuel overflowing from the carbs. Not sure where to start looking.

Would first rule out gasoline intrusion into the crankcase.
Use the sniff-test and examine the physical quality of the crankcase oil.

Good Fortune!

At most, if I ride the bike without really ripping the throttle open, I get 200km on a tank. If I really ride hard, I might see 170km to a tank. '78 kz650 with a 720 big bore, 4-1 pipe, stage 3 jet kit, and pods.

Is the 180km after the full tank or is that when you must switch to reserve? Ed

mackinnon0909 wrote: Finally got my 78 kz659sr on the highway but I'm only getting 180km out of a tank of gas. Power seems good through the rpm range, and can't see any fuel overflowing from the carbs. Not sure where to start looking.

Exactly how many gallons are being burned to travel the 112 miles?

Good Fortune!

Fill the tank. reset the odo trip meter. ride 160 km. fill up the tank. do the math to calculate your kpl. repeat as necessary. report back.

Just switched to reserve and put in 11.3L so not so bad for 180km. Its been at least 4 years since that bike has seen the highway and is my first real bike so wasn't really sure what to expect.

mackinnon0909 wrote: Just switched to reserve and put in 11.3L so not so bad for 180km. Its been at least 4 years since that bike has seen the highway and is my first real bike so wasn't really sure what to expect.

Equates to a little over 37 mpg.

Good Fortune!

37 mpg is not abnormal on my KZ650. It depends on how hard I'm riding. I've gotten from low 30's to mid 40's. Ed