Fuel Consumption vs. Gearing

[wallie_555]

Just had a nosey around the forums and found that everyone else seems to be able to get about 100+ miles at least to a tank, where as i struggle to get 80/85. Its got a Yamamoto half system that was fitted and set up when i brought it, and the jetting seems fine.

However i do have strange gearing with a 43t rear sprocket (with 38t standard), would the extra gearing be enough to have that much of an effect on the extra consumption?

Ta
Tom.

[CMSMJ1]

Yes/ as for the same speed as someone on a std gearing you are pulling much more revs...and so using much more fuel.

[alexwitham]

I run a far from standard NC30 on -1 tooth at the front and still get 100mile's before hitting reserve

[wallie_555]

The gearing must be contributing to it but i cant see it being much else, as i said its only got a pipe on engine wise. I had the carbs stripped and cleaned a few months ago and it doesnt seem overly rich.

Strange lol.

[amorti]

Put it on a dyno for a quick a/f readout if it bothers you much.
Other than that gearing only makes a big difference if you're often at cruising speeds, otherwise just give it less full throttle, gentler breaking and change up earlier, see what tanks turns out when you rode as if you care

[trademe900]

I've done quite a bit of fuel economy testing on these bikes.

With stock gearing you should be able to get 3.3l/100km.

It's pointless trying to measure with different sprockets as your speedo will be thrown out.

[Cammo]

You'll get best consumption if you keep teh carb needle at teh factory setting also.

Many owners raise the needle making the midrange (where the bike spends most of its time) richer.

[Neosophist]

What is your jetting like?

A dyno run will also give you a fuel graph which will show you how lean / rich it is running throughout the rev-range and an indication of how healthy the bike is, this might be a good place to start for peace of mind.

Changing the gearing will affect the speedo to a degree, if its under-reading (ie your doing 85 when your doing 100) then the miles it records will be lower so it will appear that you are doing less mpg than you actually are.

Using a GPS you could work out how far it over-reads at certain speeds and calculate an average to work out your correct mpg.

3.3 l/100km (71.2771465 miles per gallon)

That seems way too conservative unless your hypermiling everywhere.

The Factory Honda Spec was 4 l/100km (58.80 miles per gallon)

6l/100km is more reasonable for a mixture of enthusiastic riding.

So Circa 40mpg.

I get 250km on the NC24 between fill ups (13 litres of fuel) which is 45 mpg (5.2l/100km)

The ZXR is in a higher state of tune and if I ride that hard I get 120 miles to a full tank (15 litres) which is 30mpg / (7.85l/100km)

The ZXR and VFR's both fuel almost perfectly throught the rev range.