Fuel Consumption Problems

[Rowey]

Hi, I recently got my old CB250n Superdream purring again, after some new plugs, and a generally thorough servicing, including getting the valves adjusted and carbs balanced, I've noticed it's using a lot of fuel. I topped the tank up, from empty, with £10 of petrol and it got me, according to the clocks, only about 40miles before I was on reserve. I put the fuel tap off whenever I set it down, to make sure it's not dumping fuel, and as far as I'm aware I'm not having any lean, rich mixture problems.

I worked it out to be about 18mpg, which is way under it's quoted 50-60mpg. I was thinking check the air filter, air box and air seals for any leaks. Anything after or before that I should check.

Any help is appreciated
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ZX6R C6F.
Never argue with an idiot. They'll only bring you down to their level, and beat you with experience.

[2006 _p1]

is there any sign of a fuel leak?

[MaybeGuy]

my bets are on the float bowls leaking.

i remember working on my 250 and my 400 superdreams, they were an absolute bastard! i never managed to stop the leaks, just slow them to maybe a drip a minute.

the best test i found was to lay a washing up glove underneath either the runoff line or the carbs (if you dont have the line)

the petrol reacts with the rubber in the gloves, and it makes a big obvious blister appear.
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[Rowey]

There was a problem with the carbs leaking through the bowl overflow, but I had the floats adjusted and it's stopped doing it now.

I always turn the fuel off when the bike is parked up, so the only time it could be leaking fuel would be when I'm riding it. Thanks for the tip Matt, I'll try that, maybe tie a glove around the two overflow pipes to "catch" any fuel that may come out when riding.
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ZX6R C6F.
Never argue with an idiot. They'll only bring you down to their level, and beat you with experience.

[Odie]

With the price of fuel going ever higher, how easy is it to open your fuel cap?
Fuel thefts have already started near me!
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You are so ugly when you were born the doctor said "I?m gonna drop it, if it falls is a rat, if it flies is a bat."

[panrider_uk]

Mine has a lockable cover. Don't most bikes these days?

I'd not thought about fuel theft tbh but there's no anti-siphon on a bike is there?

Mark
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Current bikes: Honda ST1100 Pan European. Moto Guzzi V85 TT Travel

[Odie]

[Rowey]

It's definitely not fuel theft, I would presume I'd lose a lot more than I have.

This week, I've managed to get about 30mpg, which is better, but still a little way off the 50-60mpg I should be getting. I've checked the overflow pipes after riding, and can't feel any fuel, but I'll try tying a balloon round them after the next fill up.

I'm gonna check the plugs out asap, see what colour they are, and whether the engine is running fine.
____________________
ZX6R C6F.
Never argue with an idiot. They'll only bring you down to their level, and beat you with experience.

[smeg918]

If your plugs are black and sooty that's where the fuel is going, is the choke definitely going off. ?