HELP BAD PETROL?

[Halibag]

Hi
So I'm riding along thinking bikes running nice and pull in to my local tesco for some petrol. Put a tenner in to brim so about the same of old fuel in. Leaves and goes about 8 miles and first indication was when feeding the throttle in after slowing for a bend I noticed it missing/ spluttering and then picking up. Accelerating still fine. Got gradually worse. On way back was really getting bad. When the throttle was closed it was like it was dead,on a steady throttle it would die then it would come back in. Still ok accelerating. By the time I was nearly home it would not tick over and would sputter then rev then splutter. Riding along it seemed to do the same. Running cutting out running. Managed to get back and drained out petrol. Checked plugs, black. cleaned and replaced.New fuel but still the same. No fault codes as I don't have standard clocks. 1st problem I've had in 9 years any ideas

cheers
Phil

[essexboydave]

It's possibly the Tesco petrol, it's not unknown for fuel to be bad. It might just take a while for the new fuel to work it's way through. Personally I never use supermarket fuel in anything as I've heard it does over time cause your engine to coke up, with the 14 as I didn't use it regularly I'd fill it with BP, Esso, Texaco or Total super unleaded as they were the ones I heard didn't contain ethanol, I also found the Guzzi ran far better on these than any other fuel so it did seem to make a difference.
Anyway back to your problem, I'd be inclined to put a bottle of Motul systems cleaner in with the fuel, I did this the guzzi when it was playing up before I learnt about the ethanol issue and it did an excellent job of cleaning the fuel injectors out and it ran a treat afterwards. I assume your air filter is clean and there are no obstructions in the air intake side? That could also cause rich running as that's what it sounds like.
Hope you get it sorted mate

[gsxbarmy]

Like Dave I won't touch supermarket fuel (unless I have no option) as frankly don't trust it and heard too many stories about issues afterwards. It's always possible you've picked up some water in the fuel which will take a while to burn off. Either that or if the (supermarket) fuel tank was low, you've picked up some crud which has partially blocked the fuel filter / injectors.

I'm assuming that you've checked all 4 plugs and all are black so the problem is common across the fuel rail.

I'd clean out any fuel filters you have Phil, then refill with either BP Ultimate or Shell Optimate as the detergents in those will help clean the fuel system out. It may well pop and bang for the first tank full though whilst it all works its way through. I'd also check things like your TPS to confirm that the readings haven't gone wildly out.

[seth]

check and clean the teebag filter on the fuel pump emma had the same a few weeks ago 20mins and a tin of spray carb cleaner and as good as new .
sounds like you might have picked up some crud in the fuel or water. either way worth checking out the teebag.
good luck buddy .

[Halibag]

Hi been out and problem still there. Dave yeah all plugs were black. Not running standard set up remember (turbo) Got a mate with a 400hp methanol injection busa poping round in a while so see what he thinks and he knows quite a bit. I'll try and ride round close to home to run the new fuel and injector cleaner through to see if it clears. I'm going to be popular. At lights you have to keep reving it to keep it from stalling and its not exactly quiet with a 2" dia by 12" exhaust.

[Timothy Spencer]

Its a natural tendency to try to blame things on something that recently happened. It is more than possible that the Tesco fuel has nothing at all to do with this malfunction and is merely a coincidence. Don't let it cloud your diagnosing too much.

[Mick_J]

One of the reasons I joined the old forum was that I had a very similar problem, bike ran crap and would not tick over, black plugs and would only run when it had some revs on it.  I checked all the usual things TPS, Valve clearances, air box etc but it only cured itself when I changed the plugs.  I put a new set of iridium plugs in (that started another argument about their worth) but my bike has run fine since.