stalling X

[2strokeYardSale]

My WR250X has been stalling lately. Always after a lengthy period of idling, usually when I click into first and feed clutch and throttle.

I've been attributing it to my fingers being frozen and my brain not paying attention, but it's beyond that. Last night, before my fingers got frozen, it stalled and took a bunch of cranking to restart.

Later while idling in a queue it died.

Something is up. The weather is colder, below freezing in the mornings. The Power Commander was dyno tuned at 101 F with 91 pump gas. I have been mixing 87 pump with leftover race fuel premix (VP C12/Motul 800), at most half a tank.

It's only used for street commuting so the air filter can't be clogged with dirt.

Isn't there a F.I. equivalent of an air screw or fuel screw I can tune?

[Toddwr250r]

Were i you i'd be concidering setting up a cold weather map for your pc 3, i'm still stock and i've ridden as cold as 19 degrees with no issues

[CopaMundial]

I have been mixing 87 pump with leftover race fuel premix

Race fuel... ok, I can see that.

Race fuel pre mixed w/ oil (as in 2-stroke gas) ... you're losing me there.

[ZX1100F1]

There is an idle screw on the left side of the TB, most likely just need to crank it a couple hundred RPM.

Any tweaks emulating an air/fuel screw adjustment can be accomplished with the PCIII.

Copa,

Guys that race 2-stroke bikes, Jet ski's, snowmobiles etc usually pre-mix the race gas with oil in a 30 or 55 gallon plastic drum, at the end of the season they will have some left over and an easy way to get rid of it is to add a little bit to the tanks of their lawnmowers, cars, trucks, bikes and whatever.

[CopaMundial]

There is an idle screw on the left side of the TB, most likely just need to crank it a couple hundred RPM.

Any tweaks emulating an air/fuel screw adjustment can be accomplished with the PCIII.

Copa,

Guys that race 2-stroke bikes, Jet ski's, snowmobiles etc usually pre-mix the race gas with oil in a 30 or 55 gallon plastic drum, at the end of the season they will have some left over and an easy way to get rid of it is to add a little bit to the tanks of their lawnmowers, cars, trucks, bikes and whatever.

Yeah, I understand what he's talking about.

I just think that if you're putting leaded fuel (with oil mixed in it) through your WRX... and it's stalling... then the first thing you should probably do is run it on good old premium pump gas to see if it stops acting up.

No sense starting off by messing around w/ your fuel tuner or idle adjustment.

[Toddwr250r]

Seems logical, copa, start with the easiest thing first

[ZX1100F1]

No sense starting off by messing around w/ your fuel tuner or idle adjustment.

Depends on how much left over race gas you got in your drum. ?

And 2StrokeYardSale; if the problem started right after you started mixing your old race gas, do you really need our assistance?

[2strokeYardSale]

More like when it started getting really cold. The cold would tend to lean the mixture out but the C12 would tend to richen it, so it's probably a draw. The lead isn't going to hurt anything; the cat is gone and the bike has a Q4 muffler.

I filled up with pump swill last night and I can avoid topping off with C12/premix for a while and see if it still stalls.

[mtb2104]

Mine had a somewhat similar problem.... but I do not have a PCIII

the cause... the battery screws...

maybe you will want to check the screws on the +/- ends of the battery as they might vibrate loose..

just my 2 cents.. ?

[mtb2104]

oops... how did the double-post happen?

I swear I only submitted once... ?

[Longview]

This may be a stupid question - but would the cold weather lean it out? I get the colder, dense air thing for carbed bikes, but don't our fuel-injected bikes compensate?

My VStrom 1000 fired right up this morning for a rather chilly -15c commute. I think that's 5 on your antiquated fahrnenheit (sp?) scale.

[Toddwr250r]

Ya, the computer is supposed to make the air fuel mix right no matter the weather, thats why my first thought was to make a cold weather map

[2strokeYardSale]

but don't our fuel-injected bikes compensate?

No, or not enough. It's an "open loop" system, basically pre-programmed. The WR250R/X does have some kind of cold air sensor or something to help, IIRC.

[sloowr6]

-----------snip-------------

Something is up. The weather is colder, below freezing in the mornings. The Power Commander was dyno tuned at 101 F with 91 pump gas. I have been mixing 87 pump with leftover race fuel premix (VP C12/Motul 800), at most half a tank.

-----------------------------

Why do you use 2 stroke mix in a 4 stroke engine? Is there any benefit of doing this? The oil in the 2 stroke mix can't be good for the valve.

[2strokeYardSale]

Why do you use 2 stroke mix in a 4 stroke engine? Is there any benefit of doing this?

ZX1100 figured it out in a previous post.

The oil in the 2 stroke mix can't be good for the valve.

Sure, whatever you say. Is oil on the valve making my bike stall?

[sloowr6]

Sorry, missed that reply.

I don't know if this is the cause of the bike stall. But in general. Oil in fuel in a 4 stroke engine is not good for valves, oil usually won't burn completely which will leave burnt on the valve surface and cause the valve not to seal properly. 2 stroke is different cause it does not have valves and it need the oil in the fuel to lubricate the cylinder.

Try swap out the gas and add valve cleaner in it see if it helps solve the stalling.

[ZX1100F1]

I'm thinking that the small amount of pre-mix oil coking the valves isn't causing the stalling unless he has been doing it for many tanks but even then it's doubtful since most high performance 2-stroke oils burn pretty clean now days.

I have tried mixing small amounts of race fuel in various 4 stroke (low compression) engines like our WRR/x machines and have noticed each time that the engine either runs about the same or worse.

If the fuel isn't causing the issue than the idle may just be a tiny bit low (my bike was from the factory) or the air intake temp or pressure sensor could be faulty, while it is true that these sensor signals only account for small changes in fuel mixture they appear to have enough effect to cover changes in varying atmospheric conditions.

[miketegra]

Might want to take a look at the plug.

I'd stick to straight 93 if I were you.

[2strokeYardSale]

I've run two tanks of straight 87 through it now without a single stall. Hmm. I'd like to put some C12/87 premix in to see if it stalls again but I'm saving it for my winterizing storage fuel.

[Socal Paul]

I've run two tanks of straight 87 through it now without a single stall. Hmm. I'd like to put some C12/87 premix in to see if it stalls again but I'm saving it for my winterizing storage fuel.

Dude, Throw that sh*t in the garbage and use some good'ole 91 gas...!