Stale Fuel

[Butch (cb)]

We were recently discussing someone's poor running issues after a Winter layup (I can't find it now). There was some suggestion that stale fuel might be the root cause, and I'd perhaps somewhat smugly suggested that mine was fine on last years liquor and that maybe this was down to the use of Octane boost and lead additive.

Saturday evening I was heading over to the speedway on my recently recommissioned H1 and realised that the jetting on that was even further out with the std airbox refitted. Returning home I jumped on the A10 as the next most feasible ride - still on last years fuel.  Not long after, running down the A120 at around 65 per I started to have the power delivery falling away. Tried popping the fuel cap whilst rolling but made no difference. Had both side fuel taps switched on. Managed to nurse the bike off the next exit and down to a small service station. Took 10 litres (and more additive), so the tank wasn't so low either.

Ran fine after. Stale fuel?

[Topdad]

I read the same posts and has I hopefully will ease mine out hibernation this week ,was going to try the fuel left as you did but maybe I'll get her going  ( hopefully ) and then top up with a gallon of fresh rubbish . re yours did the motor get hot has it slowed down or any other warning signs ? The plot thickens sure there'll be more input on this, lets know if any further symtoms show ,best of luck BobH.

[Butch (cb)]

Don't think she got too hot. It's an all iron motor and always feels hot anyway. My headers are lagged hot rod style and one of them was smoking a little when I pulled up to the pumps but I'd guess that was some minor spillage burning off ... maybe. The motor never felt tight.

As I say it started off feeling a bit 'flat', this was on the A120 dual track so running a constant throttle. Easing off a bit seemed to help, winding on made it worse. I probably still managed 50 per limping off at the first exit. Thought the bike might die altogether slowing for the roundabout at the top, but kept it going another quarter mile or so to the filling station. As noted I'd already tried popping the cap off in case it was pressurising, and had both taps switched on.

And fine for the 55 odd miles I covered thereafter heading out and then returning. I might just try cleaning the filters on the taps and the carb.

[BSA_54A10]

Yep.
Fuel ( which is not petrol) can vary greatly from day to day.
Some will last for ages while other will go bad as you put it in the tank.
modern "fuel" is all the junk left over after they have made Jet A1 and avgas.
The reason why we have to pay $ 1000 extra for our cars to have a catalytic converter ( bull shit talk for afterburner ) is because the crap we are buying is so bad that a computer controlled fuel injected long duration ignition engine can still not burn it properly so we rely on a red hot lump of platinum to finish the job.

Unleaded was the greatest con job of the 20th century and the buying public fell for it hook line & sinker.
Lead compounds formed in your engine at combustion temperatures & pressures are not soluble in your body no matter how you injest them.
And neither is metallic lead which was used to make fuel tanks ( ternplate ) and storage tanks for hydrochloric acid ( which is what is in your gut ).
lead oxides used in paints is a totally different matter

[Topdad]

Just my two penny worth re the stale fuel issue. Brought my P&Joy to life yesterday. New oil in everything and tickled the carb, fired up on one ,second kick  ran smooth as soon as choke whipped-off 5seconds at most. Got her nice and hot after waiting for the oil return .Seems fine but will top with new fuel today,  regards bobh.   

[jachenbach]

Here in the USA, with 10% ethanol, I've found the effects of old gas tremendously variable, depending on the bike. I'm a BMW tech, and within the BMW model line, the F650/800 twins have been the most sensitive by far. Of my own bikes, the only problem I have is with a 1980 Yamaha XT500 with a Mikuni carb. Clean the carb and it starts first kick, runs great, idles fine. Leave it sit for a month and it won't start at all.