Symptoms of crappy fuel?

[Peril]

Since trail riding on sunday,the XT has developed a few issues.
Put $15 of fuel in at Caltex Bishopdale,rode round for the day,seemed fine.But on the way home the bike suddenly felt flat,the head temp on the trail tech speedo peaked at 265 degrees and the bike is holding around 2500rpm when slowing down,then the idle drops back to normal.
Also missing/hesitates up top and sounds like the piston wants force it's way out of the engine when loaded up in 4th.
Could it be a bad batch of fuel I've been unfortunate to buy?

Also there are no air leaks that I can find.

[3umph]

drain fuel and put fresh load in to see if any different...

if there is then a good chance of crap fuel

[LittleJohn]

Also you may want to do a quick check of the carb, if it is bad fuel it may also have dirt in it, nothing worse than small grit runnning through your carb.

[Peril]

I do have filters mounted inline,they seem clean and added some new fuel last night.
Just gave it a bit of a fistful on the way home and gives a wee cough then surges as it starts to (slowly) wind up.It's got a lean feeling to it as if it's not getting enough fuel.So I'm hoping it is bad fuel and not something more serious.

[LBD]

Top up with premium ASAP....

it sounds like a dose of low octane fuel. Particularly noticable at lower rpm high load like when twisting the throttle in 4th gear.

I would be surprised if the problrm is still there after a top up or 2.

[AllanB]

Dump the fuel and replace. See what happens.

[Peril]

Just to satisfy my own curiousity,I ripped the carbs out to find them spotless.
New fuel will be going in tomorrow morning,here's hoping the local Shell hasn't got a bad batch also.

[hmmmnz]

my money is on valves/ clearances, your symptoms sound exactly like issues i had on my zxr, i'd check the clearances

[awayatc]

Pull out
SPARKPLUG
and replace.....
Or if you are on a tight budget clean/soak in petrol....

Problem solved

[Peril]

Just to give you guys an update.
Turns out the charge coil is starting to fail.Has gotten worse since my last post,to the point where the bike sounds like an armed offenders squad xmas party gone wrong,eg lots of backfiring.So it's in the shop at the moment and no doubt the stator will be re-wound.