Fuel consumption

[kenzo]

I realise that Firestorms are well known for low MPG and have tried to track down references in the Forum.
I rode two before buying mine. The first felt almost unrideable, harsh and powerful. The second was similar but more controlable. The one I bought was tested in pouring rain on a muddy side road so I didnt do anything with throttle except check that there were 6 gears. I* now find that it is very tractable and easy to ride but hasnt got the "grunt" the other two had. They all had about 16,000 miles on clocks. I do about 20 miles a day of mixed commuting and open roads and do not take it much above 5,000. It is giving me 20MPG...
I thought it might be running rich as it seems to have more go when the air is cold, so have thought I should chnage air flter as a first intervention. Is the standard one the best option? What else could be causing high fuel consumption and lack of "grunt"?

[Wicky]

20mpg that's a tad low if you're keeping it below 5k revs - though are you lugging it around in too low a gear. Yes try a good thorough service with air filter, plugs etc. so you can get a better baseline. The downloadable PDF Service Manual is in the Workshop Knowledgebase subsection to the Workshop section.

What mods have been done to the bike such as cans and jetting? Does it have an OEM filter or an aftermarket K&N type?

[bluestoesonnose]

Seems low for even for a Storm. I'd be checking for air leaks after the carbs (a can a WD-40 can be used for this) and then setting the carbs up again.

Could be worse a mates rebuilt Laverda Joto 180 did just over 17mpg on a run last week!!!

[VTRDark]

Sounds like my bike except I don't ride at 5000 generally

Standard airfilter is best for tuning the carbs and fuel consumption. As bluestoesonnose said give the carbs a good going over, especially if your running cans with no baffles. There are many things that can cause excessive fuel, fuel tap diaphram, badly jetted carbs, leaking hoses, general wear and tear, timing. Do you know the bikes history? Has it had a cam chain tensioner fail in the past? the timing may have been set a tooth out.

(:-})

[bluestoesonnose]

Just a thought and I know I always say this, but when was the bike last serviced? And I mean a full service, plugs, oil, filters, and the Vv clearances checked, carbs balanced, etc, etc, etc? Also are any of the brakes binding a sticking brake piston can really hurt your MPG. Finally ok your riding at 5000 rpm, but how are you getting there, nailing the twist grip or rolling it on, are you braking at the last minute and then gunning it, try smoothing out your riding style you'll be surprised how much fuel you'll save.

[kenzo]

All very sensible advice and observations.
The bike has a full service history and I asked that the valve clearances were checked before I bought it at 16,000 which is part of that service. I suspect that the bike has NEVER been serviced in the way that people are suggesting and which should be the case ie it got its oil and filter changed, tyres replaced, chain adjusted etc - all the easy stuff that anyone could do. Balancing carbs etc? unlikely I suspect. I was hoping not to have to get involved in any of this as I have a number of bikes and just want them to work as they are supposed to. If Firestorm was my only bike I might build up a better relationship with it and want to get to know its inner most secrets. Evereything is standard so I will start by getting tank off and looking at filter and carbs as suggested...Thanks.
Ken

[Wicky]

Evereything is standard

Including the CCTs and if an early model is the R/R an unfinned self-cooking unit?



Sounds like it just needs a thorough fettle to get it running sweetly and reliably longterm.

[bluestoesonnose]

I think with a bike of that age you'd have to expect to do something. Ok I admit I'm a fussy bugger but I'd be looking at rear shock linkages and head bearings. Lack of use can kill these things quickly when you start using the bike again and the lube has gone hard or MiA. And the brakes may need new fluid, it would also be worth dropping the coolant as well unless it's been done in the last year.

[Stratman]

My Storm returns 42 mpg on a steady run and about 36 mpg otherwise. No way will a properly set up Storm ridden properly only get 20 mpg. Same as those who say they only get 80 miles to a tank - your bike isn't set up properly.

[AMCQ46]

The first felt almost unrideable, harsh and powerful. The second was similar but more controlable. The one I bought was tested in pouring rain on a muddy side road so I didnt do anything with throttle except check that there were 6 gears. I* now find that it is very tractable and easy to ride but hasnt got the "grunt" the other two had.

its this comparison thats puzzling me. I would never class the storm as "unrideable, harsh and powerful", but if you think by comparision to the others you rode your new bike is too soft and gentle there must be something wrong.

blocked fliters, cam timing 180 deg out, choke stuck on, bike jetted for K&N / race cans but those bits have been swapped back to stock and its now too rich,

[bluestoesonnose]

I keep going back to carbs, I don't disagree the fruit may have been taken off it and flogged on ebay and now the bike runs like an asthmatic fat boy

[T8ull]

I get 36 per gallon, weekend low mileage stuff. Bit frightening when it equates to a litre of fuel for 7.5 miles!!! ( 16 litres is 3 galls) that wouldn't sell me one if I was thinking of buying one!!

How much is in the tank when the light comes on? I sh1t myself generally when it does!

[Rampant Lion]

My tank I believe is 16 litres being a 1998 model. On a run down the motorway at around 70 - 80 and on a run to a rally on A roads I find my light comes on between 100 and 110. Can't remember now what it takes to refill but it's constant.

[kenzo]

Well it looks like the norm for these bikes is between 36 and 42 mpg which is fine. My bike is an 04 model, and does not look like it has had anything untoward in its life so I am optimistic that it just needs a proper service / re setup.
The first Firestorm I rode had Goodrich brake lines and pretty worn tires but with only 8,000 on clock. Perhaps it had been used as a track bike and received some tuning of some sort? The slightest throttle had it lurching forward and you could almost feel every power stroke. If you set off from lights and a car in front was less than 20feet away you had to brake and pull in the clutch...
I have ridden bikes for the last 40 years without a break. Not literally of course....
Thanks for advice.

[kenzo]

Just to round this thread off...
I checked compression, timing and carb balance and found them all to be in order.
Put bike on dyno and all the figures and graphs were good - 100bhp, good torque and fuel/air in correct lambda zone.
What did show was that fuel / air was at rich end and up to 4000 rpm even richer before settling into zone.
So, more efficient above 4000 rpm. Filled up and rode at 90 - 100 down motorway for 40 miles and. Refilled. 37mpg. Since then thrashed it around Derbyshire and got same figures.
I will drop needles a little and keep the revs up!