vapor lock, and more
marquis1968 at yahoo.com
Tue Aug 11 05:27:00 PDT 2009
This kinda stuff is the reason i ALWAYS spend 3-4 dollars for a manual shut off and put in the line (with a filter ) cheapest insurance i know against a whole lot of problems!!!!!!!!!!! Chris
--- On Tue, 8/11/09, Drew Blanchard <drewblanchard at gmavt.net> wrote:
From: Drew Blanchard <drewblanchard at gmavt.net>
Subject: Re: vapor lock, and more
To: "Bob Nelson" <majordad at carolina.rr.com>
Cc: "GPZ LIST" <gpzlist at micapeak.com>
Date: Tuesday, August 11, 2009, 7:54 AM
Ah, well, this is not what I expected to hear. And I DID just have the
carbs cleaned and adjusted by my local Kawi dealer (picked up some gumbies
before I installed the fuel filter, and also needed the pilot jets
adjusted). So, this points to a bigger issue? The petcock has NOT been in
"prime" position. I've noticed a whiff of gas around the bike for a while,
but it was faint, so I put it on the back burner.
When I pulled the tank, the petcock continued to dribble. Ultimately, I had
to prop it on its side and lean it againt the wall (the tank is less than
1/2 full) before I could walk away and work on the bike. This lends
credence to hydrostatic lock; the cylinders, especially 2 and 3, has LOTS of
fuel in them. At the time, I was focused on vapor lock, and worrying about
geting home before my dogs exploded from a loooong day. It never occurred
to me there shouldn't be so much gas in the cylinders. Now I need to figure
out how to get the back to the dealer's.
Thanks for the input, Bob!
Drew in VT
On Tue, Aug 11, 2009 at 4:05 AM, Bob Nelson <majordad at carolina.rr.com>wrote:
> Drew, first things first, if the motor wouldn't turn over and you had gas
> squirt out of one or more cylinders after you pulled the plugs, it was
> hydrostatic lock, not vapor lock. Hopefully you only had one flooded
> cylinder. There are two requirements for this to happen. First, you had to
> have gas flow out of your petcock without vacuum applied to the petcock (or
> the petcock is in the Prime position, if that is the case switch the petcock
> to the normal or run position). The second requirement is a stuck/leaky
> float valve in the cylinder involved allowing gas to over fill the carb and
> drain straight into the cylinder.
> If you are lucky the flooded cylinder was one of the outside carbs. I say
> lucky because I am pretty sure you can pull the float bowls without pulling
> the carb rack out of the engine. If so, you can make sure that the float is
> free to move and not stuck open. If it is free to move, then after putting
> the float bowl back on, I would tap the float bowl repeatedly as I put the
> petcock in prime to try to help the float overcome any stiction and
> hopefully float and thereby close the float valve. If the float is stuck
> open, you will need to disassemble, clean and carefully watch the first
> couple of times you start the bike to make sure your cylinder doesn't lock
> again. If you are unlucky, bad things can happen after hydrostatic lock.
> You could end up with bent valves.
> Anyway, if this occurred out of the blue and not immediately following some
> carb cleaning and reassembly, you might have fallen victim to what I
> suspected happened to me. This March I rode from Charlotte to Florida with
> some friends after not having any problems for a very long time. The next
> morning I had a cylinder locked. I attributed it to contamination from
> running way down into the reserve on my fuel tank and running some crud
> through that partially blocked the float valve open. After I cleared the
> cylinder and rode that day, the problem didn't recur.
> As far as follow on leaking not associated with the locked cylinder, that
> would have to come from a leaking hose or the fuel tubes that connect the
> carbs. Hopefully you will just find that your fuel line is cracked since
> that would be the easiest repair. But that also points to a bad petcock
> since you should not have fuel flow through the petcock when there is no
> vacuum present to the petcock unless it is in the Prime position.
> Hopefully this rambling makes sense to you and helps. Good luck!
> Drew Blanchard wrote:
>> After a chilly start to the day, temps went into the upper 80s. Looking
>> forward to my ride home, I thumbed the starter and was rewarded with a
>> brief "thump" and some starter whine, but that was it. Motor didn't turn
>> over, and the starter seemed to be trying to move an immovable object.
>> Fearing the worst but knowing everything had been fine on the ride into
>> work, I pulled the tank and plugs to see if the motor would move without
>> compression. Yup.
>> Note to self, remember to stuff rages very tightly over the spark plug
>> openings. Messy. Very messy.
>> When reassembled (and what a bitch it was reconnecting the fuel line) the
>> motor initially made the same noise, then turned over with ease.
>> it was vapor locked. I never had this issue on my '95, but that was also
>> stock set up. Anyone else have this issue? Is there a preventative
>> I can take?
>> Didn't get to ride the bike home, because somewhere, somehow I have a
>> fuel leak. If I didn't know better, I'd say the leak was coming from the
>> bottom of the motor. And landing directly on the exhaust pipe. I was
>> fortunate the motor never actually started. Every time I turn the motor
>> over I get a nice, steady drip, and I can't see where it's coming from.
>> worked on the bike for several hours in the heat, and quit for the day.
>> Fortunately, our maintenance guys at school let me put the bike in their
>> garage for the night. Once on the center stand, no leak. Moving the bike
>> or leaving on the side stand = leak.
>> Drew in VT
Winooski City Schools
Winooski, VT 05404
(802) 655 - 3530 x6073
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