Rain induced backfire?? Possible?

[DanMach]

So my bike got frigen *soaked* at work today. Its been soaked a few times before, but this was the first time in 6 or 7 months. It started fine, I let it idle for a bit over a minute as I geared up, and took off.

It was fine for about half a mile then suddenly BANG! Backfire. Loss of power, felt like only had power on 1 cylinder, then about 20 seconds later(was pulling off to a hotel parking lot), BANG! Backfire.

Started running again.

I pulled over, let it idle, got off and checked everything. Oil was fine, everything was good, no leaks or sparks, so I got on and rode it the 20 miles home. No more issues. Ran fine, no odd vibrations or anything.

So I'm wondering, has anyone had this happen before? It wasn't raining when I went home, it had rained about 2 hours ago but it was pretty heavy. I know the sv650's will sometimes lose power in the front cylinder from water on the spark plugs.. but first time this occured on the 400j.

 

[Lou Ranger]

Any chance that your fuel cap doesn't seal properly and heavy rain could have filled the little channel and penetrated?
Any chance rain could have soaked your air filter and then got sucked in with WOT ?

 

[DanMach]

Yes its possible water could of gotten through the gas cap.. it is a new cap, with a new seal, but its still possible.

The filter and air box is 100% stock and so its that solid seal mechanism with little intakes under the seat. I don't think it would of gotten soaked, but possible... hmm I didn't think of that at all!

Thanks lou! Its been too long so it'd be dry by now, but if it ever happens again i'll check that.

 

[Lou Ranger]

Yes its possible water could of gotten through the gas cap.. it is a new cap, with a new seal, but its still possible.
The filter and air box is 100% stock and so its that solid seal mechanism with little intakes under the seat. I don't think it would of gotten soaked, but possible... hmm I didn't think of that at all!
Thanks lou! Its been too long so it'd be dry by now, but if it ever happens again i'll check that.

Yeah, I imagine dampness doesn't linger in PHZ this time of year, and condensation is likely out too. The only thing that makes me think H2O is that a drop or 2 can pass through without leaving anything plugged or damaged (which hopefully is what's happened) - not often the case with the stuff that an in-line filter takes out. Did you put one in by the way?
Everyone has me convinced that there is a particle lurking out there waiting to mess up my carbs. I want to go 2 years like HoughMade and still be clean as a whistle - I can hardly bear to read about all the carb tribulations on here.

 

[DanMach]

Ya I have an inline on there. I was going to take it out today but I pulled the tires to get new rubber put on. Everything is closed so it has to wait until tomorrow.

 

[drewpy]

just spray the ignition system with WD40 type stuff. Its got to be ignition related.

 

[DanMach]

Dielectric grease everything to hell?

 

[drewpy]

yep, that's good too but a bit messier.

 

[sprocket]

yeah but it lasts while WD40 evaporates and you need to reapply regularly.
It's only as messy as the person who applys it

 

[drewpy]

yeah but it lasts while WD40 evaporates and you need to reapply regularly.
It's only as messy as the person who applys it

not heard of Dielectric grease wrestling then

 

[sparky]

Is it backfire or afterfire? Afterfire is from the exhaust whereas backfire is through the airbox. Sounds to me like an iginition afterfire. There may be a crack in one of your plug boots or in your ignition wires. The water seapage can create a short between the wire and engine head causing an ignition misfire. Then the unburnt air/fuel mixture is being passed directly into the exhaust pipe where it is reaching it's flash point and igniting in your exhaust causing the afterfire .

If the ignition wire has any cuts in it then you will most likely what to replace it or temporarily fix with shrinktubing but if it is the plug boot then replace the boot.