Fuel crystallization?
 

Hello everyone.

maybe asking something very basic, but somehow this thing gets important first time during 6 years of riding this bike ('02 xt600e).

(this color might be skipped by more experienced people).
few days ago in some mountains engine suddenly become very weird at some throttle openings - maybe from 1/4 to 1/2: unstable revs, much more shaky, backfires... obviously accompanied with negative emotions and crazy fuel consumption.
actually for the first time it happened right after ~3 mins of rather continuous engine braking around 2500m of altitude, when descending on sharp downhills.
tried to still continue riding. few minutes and somehow everything is normal again.
working title of this thing was "altitude sickness" by that time.
it was long ride to home and during it this syndrome used to appear and disappear randomly, and the range of unstability also changed randomly: sometimes from 0-1/4, sometimes 1/2-3/4.
starting was not always easy.
highest revs seemed generally better.
after normal conditions, cold/higher places used to trigger this syndrome to appear again.
couple roadside draining of carbs did little to no help.

finally got home and removed carbs.
was surprised with this white somehow solid, but very flimsy and dry thing, looking like thin film of fine crystals stuck together, habitating mostly in primary carb and not only. a bit in secondary. around fuel cap center. at the endings of draining pipes etc.
https://i.ibb.co/ZhhLpzs/IMG00109.jpg

https://i.ibb.co/zXZxm2x/IMG00110.jpg

https://i.ibb.co/myJqg4H/IMG00111.jpg

all jets / needles, float, fuel container, pipes etc. were clean at the moment of disassembly.

despite of always getting fuel at trusted network of fuel stations, only guess for now still is a bad fuel.

well, obvious questions are what the #### is this thing and how to avoid it happening again.

do you know if they add any ethanol to fuel in georgia?


in any case, this is not an XT specific problem, I bet you get LOTS more response in one of the general HU forums, here there is hardly any traffic...

If it doesn't happen again I'd go with the contaminated fuel theory. I once had a bad batch, it was from a station that didn't sell much fuel so I guess water got in or the higher fractions had evaporated off leaving poor quality behind. Some petrol station owners in some parts of the world *might* add stuff to their tanks to bump up their profits as well, you never know.

thank you guys for answers.

turboguzzi, ethanol also appears one of my assumption. in earlier times definitely no. hence it is somehow unknown to me - only thing i'm aware of is that ethanol is able to absorb some moisture from atmosphere and will encourage steel tanks to rust.
will wait for monday and try to find out something in official ways..

Tomkat, in the country where i live it's not surprising at all when big or small business owners make shitty things for more profit.
on the road back had to refuel twice (more than half of the tank each time) on different stations and seemed that it made no difference - this crystals appeared both time on tank cap.

meanwhile, talked to some friends with carbureted bikes and appears that since recently, they also had same issues with more or less troubles. and same complains from delivery gang on scooters. really seems like some recent general changes in fuel supply here. maybe even ethanol. just have no idea if fuel with some ethanol could do such things.

We (Colorado USA) have been using ethanol (up to 10%, I think) for years. I've never seen crystals form like that.

Ethanol does seem to 'go bad' more quickly, 6-8 weeks is a long time for it. But it turns greenish and kind of slimy when it does.

I wonder if some cretin sabotaged that bike with something that does crystallize- like sugar or salt in the tank.

Have you been chatting up people's wives at the bars, or cheating in card games? :nono: (just kidding).

Whatever, that doesn't look so good, does it?

................shu

shu..., thanks for sharing more info about ethanol.

won't think about any sabotage, since bike was used on daily basis in quite remote places with no bars and no bad intentions ( :
getting back and discovering that now this syndrome appears not a rare thing around.

and yes, that's exactly how the carburetors should not look like.

Looks like ice to me? Does it melt?

Icing is an ethanol/water problem. The ethanol concentrates any water in the tank and has less energy so the whole cycle of more concentrated water and less heat promotes ice.

My 2003 XT was a swine for icing.

Andy

I think the they add ethanol right across the USA, no choice. (from reading on this forum).

Mezo.

Hi Andy
somehow it looks like an ice, a fine hoarfrost to be more clear.
it does not melt by itself at ~20c, but is not sticky and goes away easily.

collect some and send to the nearest chemical lab.... mistery solved...

White crystals? Are you sure you want someone to analyse what they are?

Is it waxy?

At 20C it isn't water ice for sure.

Something like paraffin?

Is your tank metal? No chance it's fibreglass residue from either the tank or an attempt to repair the tank?

Andy

turboguzzi, it might not be very easy but doable - still keeping this old fuel and with some more time might try to find it out.

Andy, it is more dry.
tank is metal and since this thing used to happen not only with my bike recently, it quite seems like some particular additive which appeared in few brands of fuels since maybe from end of the august.

meanwhile, some updates for now - emptied/rinsed the tank, tried fuel of other brand which couple friends have suggested, as it so far was not seen be crystalize. had a short test ride and so far everything going well.

about ethanol in georgia - seems that it not being used as ICE fuel.
couple companies stated this straight, but ways of answers of some others made me more sure: "etha..what?" : )