vapor locking?

[shadowmagic]

So my valk was parked for a few months but started regularly. I took it out today and it rode fine for half an hour. I made a quick stop, it started right up and ran fine. stopped to eat with some friends so it sat for about 2 hours. Started up and drove fine for about 5 minutes then started trying to die out. I had to keep hitting the throttle to keep it going but it sounded terrible. I got it on the freeway and rode find for a bit then started sputtering like when your gas is running out. I had just put gas but switched it to reserve anyway. It ran that way for a mile or two then cleared up and ran fine the rest of the ride. I've had a lot of problems with this bike as I'm sure most of you know, I'm paranoid now about taking it out. Anybody have any idea what could have been the problem? I cleaned out the carbs and everything before storage. As usual, any help or advise is greatly appreciated.

[The emperor has no clothes]

Sounds like a new cover set or vacuum line to the petcock is needed.

[shadowmagic]

I'll check those out tomorrow. Do you mean the six piece covers for the carbs? Those seem to look good when I did the carbs, I'll check the vacuum line tomorrow. Thanky you for the quick reply.

[hubcapsc]

I'll check those out tomorrow. Do you mean the six piece covers for the carbs? Those seem to look good when I did the carbs, I'll check the vacuum line tomorrow. Thanky you for the quick reply.

He thinks you should rebuild your petcock (#3) with a cover set (#5)

COVER SET, PETCOCK
16953-MBZ-B51



-Mike "I'd get #4 and #6 too..."

[The emperor has no clothes]

Thanks, Mike. I should have been more specific. 

[shadowmagic]

petcock is new, about 6 months old. I replaced it because it was leaking. It might be the vaccuum line, I'll let you guys tomorrow what I find. Thanks again everyone.

[hubcapsc]

If you turn your petcock on and disconnect your
gas line, no gas should flow out. If you then disconnect
your petcock's vacuum line from the intake runner and suck
on it (I'd use a syringe or something  ) a real good stream
of gas should flow out of the petcock...

-Mike "avoid catching on fire..."

[Jruby38]

Best advise is replace the gas valve with a Pingle. You will never out run its gas flow.  The only thing worse is the cheep wrinkle plastic chrome.

[Jess from VA]

In an emergency (no run) situation, where the gas flow might be vent related, you can close the gas cap on a small zip tie to keep some venting going on top.  If that's the issue. 

[hubcapsc]

You will never out run its gas flow.

Even when you're bike's turned off  ...

Anywho... if you don't mind a pingel's limited reserve and
are willing to turn it off and on every time you get on an
off your bike, a pingel can be a good option. I like
the OEM...

-Mike

[-mike-]

Nothing wrong with the OEM petcock.
It's the pulsing trigger vacuum that destroys its internals over time when the rubber ages.
The non Honda diaphragm replacement kit will go south even faster.

The OEM "COVER SET" will last, but not forever.
That's why so many go simple with a Pingle, which has its limitations like hubcapsc said above and doubles the risk of a hydroloc... if you don't religiously turn off the petcock manually after each and every ride.

If you decide to rebuild the petcock, just put a low pressure snubber into the vac line.
You'll never have to service the OEM petcock again.

-mike-

[Valkorado]

Nothing wrong with the OEM petcock.
It's the pulsing trigger vacuum that destroys its internals over time when the rubber ages.
The non Honda diaphragm replacement kit will go south even faster.

The OEM "COVER SET" will last, but not forever.
That's why so many go simple with a Pingle, which has its limitations like hubcapsc said above and doubles the risk of a hydroloc... if you don't religiously turn off the petcock manually after each and every ride.

If you decide to rebuild the petcock, just put a low pressure snubber into the vac line.
You'll never have to service the OEM petcock again.

-mike-

Interesting.  Never heard of these "snubbers".  Any more install tips, like where in the line is best for placement?

[Daniel Meyer]

Check your tank vent line.

[shadowmagic]

Thank you for all the great info, you guys have been awesome. I'll check out the options. I already turn my gas off pretty religiously after first reading about hydrolock and being paranoid with a used bike. Anyway, thank you all again for the great tips.

[Jess from VA]

The best way to train yourself to always turn off the petcock is this:

When the bike is turned off with the key on one side (and key pulled), reach over and turn off the gas on the other side.

I won't do it stopping for a few minutes to take a break and drink some water out riding, but I do it putting the bike away in my shed every time.

[shadowmagic]

vent hoses seem ok. I wonder if its possible I had some condensation or something in my gas lines? I'm gonna ride it tonight and see how far i get before I hear any sputtering....if any.

[gordonv]

You've had your tank off, I'm betting on a pinched tank vent line, like has been mentioned twice already. That zip tie in the filler cap is to break the seal so air can get in.

Also, a new to you bike, have you drained/check those hoses going to the bottom of the back of the engine?

[shadowmagic]

Drained the hoses? The hoses sticking out of the bottom about a foot away from the rear wheel? What do you mean by drain them? No i havent done that.

[Jess from VA]

The drool tube?

On the kickstand, look under the bike on the right, just behind the driver's foot peg.

There's a few tubes hanging down there, and one has a cap on it. 

Use a needlenose to squeeze the clamp, pull the cap and release the drool.  Replace the cap. 

It may only be two tablespoons, but after all day rain rides it can be more.

[shadowmagic]

I will check but I'm pretty sure there is no plug on any of my hoses down there. They are all capless as I recall. I'm assuming thats gonna be a problem?

[The emperor has no clothes]

I will check but I'm pretty sure there is no plug on any of my hoses down there. They are all capless as I recall. I'm assuming thats gonna be a problem?

No, it’s not going to have anything to do with the problem you are having. Although you need to get the cap in. It will let oil drip right down into the path of your rear tire otherwise. You had said your vent line appeared fine. But it’s really hard to tell that without removing the tank (or lifting it up a little). I’m still thinking it’s the vacuum line to the petcock.

[Jess from VA]

An uncapped drool tube is also a small vacuum leak. 

[Skinhead]

An uncapped drool tube is also a small vacuum leak. 

It actually isn't a vacuum leak as it attaches to the air cleaner housing before the carburetors.  It does allow unfiltered air to bypass the filter if uncapped.

[The emperor has no clothes]

An uncapped drool tube is also a small vacuum leak. 

It actually isn't a vacuum leak as it attaches to the air cleaner housing before the carburetors.  It does allow unfiltered air to bypass the filter if uncapped.

I don’t see how it would have any effect on fuel delivery also.

[shadowmagic]

Ok, I'll cap the line and replace the vaccuum line just to be safe. Thank you everyone for helping out.

[Willow]

I know this thread is a bit old now but nobody suggested that it sounds like a bubble forming in the fuel line.  It especially happens with an improperly installed quick disconnect to the petcock or with any extra line added between the petcock and the carbs.  That usually happens when someone adds an inline filter.

The bubble most often, but not always, occurs when it's hot outside.

[Avanti]

I know this thread is a bit old now but nobody suggested that it sounds like a bubble forming in the fuel line.  It especially happens with an improperly installed quick disconnect to the petcock or with any extra line added between the petcock and the carbs.  That usually happens when someone adds an inline filter.

The bubble most often, but not always, occurs when it's hot outside.

I had an in-line filter which worked fine for thousands of miles. It caused a vapor lock in mile twelve of a long uphill run pulling a trailer in 80 degree temperatures. The three right side carburetor bowls were completely dry of fuel. I turned around and went back down the hill to a auto parts store, pulled the fuel tank in the parking lot and replace the filter with fuel line.
I change my fuel filter belief/theorie.
Fuel filter + heat + high fuel consumption does not work.