RAIN ONLY fails ignition - Master Sleuths Needed to Troubleshoot!!!!

[Jersey]

I need help figuring this one out.  Situation:
1. 1999 I/S about 70k, OEM coil/wires/cap, NGK DPR7EA-9 Plugs .34 gap
2. Engine shuts down riding in moderate rain for about 5-10 miles at 55-60mph
3. After applying WD-40 to Sparkplug boots and lower wires engine restarts quickly (slight initial rough) but smooths out after a few revs.  Notice WD-40 to #2 cylinder (Front Right) seems to have most dramatic improvement.
4.  Continue driving about 3-5 miles in moderate-heavy rain at 50-55 mph, engine progressively cuts out and eventually quits.  More WD-40 but doesn't restart right away. Eventually Restarts after a 3-5 minute wait.
5. 3 miles quits again, more WD-40, but takes a 10 min wait before restarting but very rough idle like spark was weak.  Once warms up to 210F seems to help and normal running returns.

During non-raining conditions engine runs fine at all speeds (70+)

NOW THE WEIRD THING:  (got home and rain stopped - go figure)
1. Start easily and Set throttle to idle engine at 2k rpm
2. Use gardenhose to start slow spray on cylinders one at a time.  Still runs.
3. Increase water to maximum, soaking all wires, boots, under tank to coil. Still runs.
4. remove left side cover and soak overflowTank/ECM area.  STILL RUNS.
5. Soak everything from front into tank/frame area, radiator, everywhere AND soak wires,boots. STILL RUNS.

So.    WTF!?

Only thing I MIGHT have noticed is at moderate speeds <50 it SEEMS to not fail in the mod-heavy rain.   Again, just seems like engine shutdown occurs only when BOTH Rain & >60MPH are happening.

I'm thinking that maybe the wind is pushing water up into a connector plug somewhere, either before or after the coils?  Just a guess.


Anyone else have this experience?  Any thoughts on what tests I can do to recreate the problem (other than riding fast in heavy rain again  )

Thanks for reading,
Jersey

[Pete]

Gas tank vent hose.
Put  a T in the hose high up under the seat to prevent  water from splashing in the hose bottom and being held there by vacuum as the gas flows from the tank.

First known occurance of this was on a 1979 GZ1300 in 1979.
Open the gas cap will release the water as a test.

[trout dude]

It sounds like its not your ignition if the water hose dose not make it happen.  You might want to try this carry an extra key to pop the gas tank open next time it rains and it dose this i  then if it goes back to normal check the vent line for the tank and make sure it has the Tee in it    I know this sounds crazy but i've seen this happen on Mitch o's bike it would only happen when he was riding in the rain
Hope this helps

[Jersey]

Pete & Trout Dude - THANKS!

That makes perfect sense as you both described.  I like the idea of a "T" high up.  Just to verify for safety,  do you just leave one end of the T open or should another hose be connect and directed downward?

Jersey

[trout dude]

Vent line off tank then the tee and a pice of hose going down and the tee open on the side

[Harryc]

Pete & Trout Dude - THANKS!

That makes perfect sense as you both described.  I like the idea of a "T" high up.  Just to verify for safety,  do you just leave one end of the T open or should another hose be connect and directed downward?

Jersey

One side open and another hose should be directed to under the bike...but I thought this was standard on Valkyries out of the factory. I know my Tourer has an open T half way down the tank vent line. It eventually ends under the bike. If it is not standard, a PO added it unbeknownst to me.

[Daniel Meyer]

I second...or third...or fourth the tank vent hose is plugged and/or "T" missing.

[mrgeoff]

When I got my 99 Tourer from PO, it did not have a vent hose at all...I put one on and put a "T" on the vent line...I actually put a "V" shaped "T" on the vent hose with the "V" facing downward...I figured that way any water or dust wouldn't gather in the "T" vent connector...So far, no problem...but you know, since I have said this , it is bound to happen...Karma...???...have had the bike for over 2 years...running great...!!!

[Attic Rat]

If I understand you correctly that when you spay wd40 on the spark plug boots it starts up. Check to make sure that the hole in the head for the spark plug drain is not clogged. If water gets in there it will cause the plug to go to ground and cause the cylinder not to fire.You can run a wire thru it to clean it out. You can do this from the bottom near the exhaust header.