Fuel Consumption KZ1000?

I just did a 110 km (68 miles) ride yesterday, all 2 lane highway, averaging around 115 kph or 71 mph. I filled before and after, so used the opportunity to calculate my fuel consumption. I used 10.15 litres, so that translates to 9.2 l/100km or 30.7 imp mpg or 25.6 US mpg. Seems to me, I used to get around 40 imp mpg mixed city/highway back when I rode it in the '80s. Don't get me wrong, I don't care about the extra fuel used, even at our prices of $1.50 CDN/litre for 91 octane (US$4.23/us gal). I'm just wondering if it's symptomatic of another issue. The engine is stock with the stock airbox (newish air filter) and stock pipes and jets. I had the valves set and the carbs synked around 2,000 kms ago. Am I expecting too much of a 42 year old bike with 70,000 kms on it?

Seems poor mpg
I get 25 mpg with my turbo 1000 . easily
Dave

I get around 40 mpg U.S. what do your plugs look like?

bluej58 wrote: I get around 40 mpg U.S. what do your plugs look like?

They tend to be dry and heavily carboned.

You should be running 87 octane
It sounds like you are running rich, are they all even in color? maybe your choke is hanging up.
The plugs should be light brown.

I'm starting to get 40-42 MPG with my 33's. Took a lot of doing. I got 30 +/- before. You should get 40-42 dependable. Checked your timing and spark advance?
Steve

bluej58 wrote: You should be running 87 octane
It sounds like you are running rich, are they all even in color? maybe your choke is hanging up.
The plugs should be light brown.

I always used to run 87, but now with ethanol in the regular blends, I thought it would make sense to run 91, which doesn't have ethanol at my pumps. They definitely look rich, but not wet. Perhaps I should run a tank or two with 87, see if it helps and leave the 91 for winter storage. I certainly go through at least 2 tanks a week during riding season.

SWest wrote: I'm starting to get 40-42 MPG with my 33's. Took a lot of doing. I got 30 +/- before. You should get 40-42 dependable. Checked your timing and spark advance?
Steve

Timing I've done by eye, but not by light. It seems to run well at all ranges of throttle, so I think the spark advance is working ok.

You need to check both with a light or it's not done.
Steve

All the 87 octane around here has ethanol , my bike runs fine on it but the gas never gets old

I don't know this for a fact but have read several times that ethanol laced fuel will drop mpg a little. Key word "little".

A compression check may be in order to see how the engine is fairing after all the miles. Lowish compression can result in poor mpg. Other things to check are spark quality, the air filter, and carb jets. If aftermarket carb jets were installed at some time in the bikes life the sizes may be wrong. Replacing the pilots with new Mikuni brand jets would be money well spent.

Nessism wrote: I don't know this for a fact but have read several times that ethanol laced fuel will drop mpg a little. Key word "little".

A compression check may be in order to see how the engine is fairing after all the miles. Lowish compression can result in poor mpg. Other things to check are spark quality, the air filter, and carb jets. If aftermarket carb jets were installed at some time in the bikes life the sizes may be wrong. Replacing the pilots with new Mikuni brand jets would be money well spent.

E10 drops your fuel mileage by about 5%. Carb operated motors need to be richened up a little bit when operating on E10. We've had E10 around here for over 25 years, never understood the whole "fuel gets old" nonsense - I store over 100 gallons of E10 per season in boats, snowmobiles, power equipment and seasonal cars. Never had a fuel related issue. Modern fuel comes with all sorts of stabilizers from the pump, so no snake oil needed.