BOOM!!!

[Honzilla]

I just came in the house from washing my 91' and when I am done washing I usually start her up and let her warm...

I found I was having trouble starting her, despite the nice 75ish degrees out side.  I set the choke and started to try again, this time BOOM!!!   Sounded like a 45 pistol!  

WTF happened?!?  After the big boom, she started, although soundly a bit sickly...  Then a minute or two later, after ginger applications of throttle, it seems fine.

Again, WTF happened?!?  Did I just kill my baby???

[TOOLS1]

Sounds like the ignition was wet, and not firing, and it built up gas in the combustion chambers that finely ignited. If it is running alright, I doubt, you killed it.
TOOLS

[shinyribs]

That BOOM is usually a sign of raw fuel in the exhaust lighting off. Could have been any number of reasons. Flooded will do it. If a plug wire(s) got wet from the wash,would not fire,let raw gas pass thru the motor,then it lit off in the pipes. Sounds like it got flooded with fuel SOMEHOW,who knows how. It makes sense that it would clear up in a bit like you described.

Fllooded- wouldnt start-  finally started-  BOOM,exhaust backfire-  ran a bit to clear excess fuel out of motor--now it runs fine.   I'd say your good is she running ok now.

Did it get very wet in the wash?

[Honzilla]

Got it quite wet...

In fact this may or may not be a coincidence, but on the last couple occasions of heavy SE Asian rain.  My bike died, would turn over, but not start.   If I was lucky enough to jump start it, she would run for a minute and die again...

I always thought that was fishy, but could never diagnose the problem myself...

[Honzilla]

I think I will replace the plug wires at my next oil change...

See if that makes a difference.  As far as I know the wires I have are OEM originals.

[rrgunslinger]

No, it is probably fine. It just for loaded up with fuel.  Sounds like Your plugs got wet and grounded out.

Harvey

On Apr 9, 2012 2:15 AM, "Honzilla [via Honda CB750&apos;S]" <[hidden email]> wrote:

I just came in the house from washing my 91' and when I am done washing I usually start her up and let her warm...

I found I was having trouble starting her, despite the nice 75ish degrees out side.  I set the choke and started to try again, this time BOOM!!!   Sounded like a 45 pistol!  

WTF happened?!?  After the big boom, she started, although soundly a bit sickly...  Then a minute or two later, after ginger applications of throttle, it seems fine.

Again, WTF happened?!?  Did I just kill my baby???

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NAML

[LukeM]

My Shadow does this from time to time, especially if I forget to turn on the Run/Stop switch.  It's not like a gunshot, but it's a decent bang when it happens.  It takes about 30 seconds at the most for the engine to recover (burning out the excess fuel, I expect).

I do remember a story about a friend of my brother, blowing the exhaust off of his Norton Commando when, while driving at freeway speed, he nailed the throttle, turned the run switch off, waited a few seconds, then turned it back on again. I think his carbs were running a bit rich.

Luke M

[Thorby]

Why I was at the dealer a couple weeks ago getting my tired, some customers, wife and husband, turned on a moped and were itching to buy it when BANG! the wife was standing behind the moped and nearly got a heart attack from the explosion.  The (dumb) salesperson nervously said "that, uh.. never ever happens" and I reassured the lady that it was normal on a cold bike that hasn't been run much.  An hour later the husband rode away in his new moped.