Vapor lock, most unfun

[Steve G.]

I've always burped mine at component #4, the line that goes to it. And it's on the left side of my bike.

I drain ALL the pressure off of here to fix it.

Don't ask me why, but it does cure the problem.

?????

Steve

 

 

Much Much appologies for the confusion. I was under my tank today, and must correct that I am not releasing pressure from component #4 in the picture, but indeed from the bottom of the petcock, which on my bike, is just forward of component #4, both of which are on the left side of the bike.

Steve

[ALdad]

Much Much appologies for the confusion. I was under my tank today, and must correct that I am not releasing pressure from component #4 in the picture, but indeed from the bottom of the petcock, which on my bike, is just forward of component #4, both of which are on the left side of the bike.

Steve

I live life in a state of confusion. It seems to feel natural for me. Now is your pump on top or on the bottom?

[jtucker]

Much Much appologies for the confusion. I was under my tank today, and must correct that I am not releasing pressure from component #4 in the picture, but indeed from the bottom of the petcock, which on my bike, is just forward of component #4, both of which are on the left side of the bike.

Steve

 

So, your pressure regulator and petcock are on the *same* side of the bike? I didn't know any of these bikes came that way. Well, I guess that's one way to fix the problem of not being able to access all of the fuel in the bottom of the tank, no?

 

PS: will you swap tanks with me?

 

__Jason

[ALdad]

So, your pressure regulator and petcock are on the *same* side of the bike? I didn't know any of these bikes came that way. Well, I guess that's one way to fix the problem of not being able to access all of the fuel in the bottom of the tank, no?

 

PS: will you swap tanks with me?

 

__Jason

Jason, Is your 2000 set up like mine, solenoid/petcock on the left and the fuel pump under the spine?

[dlaing]

So, your pressure regulator and petcock are on the *same* side of the bike? I didn't know any of these bikes came that way. Well, I guess that's one way to fix the problem of not being able to access all of the fuel in the bottom of the tank, no?

 

PS: will you swap tanks with me?

 

__Jason

unfortunately that does not work. The fittings are wrong.

I'll bet you Steve G. has the normal setup.

Petcock and fuel level on left, pressure regulator on right, pump down low under tank, and filter up high under tank.

I suppose that means there is less evidence now that my patented vacuum trick would work

 

If you put pod air filters on, is there enough room to relocate the fuel pump and maybe the fuel filter where the airbox was?

What is the Tenni layout? pump near the oil cooler?

[Steve G.]

I live life in a state of confusion. It seems to feel natural for me. Now is your pump on top or on the bottom?

 

 

I've got a pre 2002 pump system, with the pump located outside the fuel tank, under the centre frame rail.

Steve

[jtucker]

Jason, Is your 2000 set up like mine, solenoid/petcock on the left and the fuel pump under the spine?

 

Yup. And if the problem occurs on my bike again, I'm going to try the filter/pump location swap first, I think. I will keep Raz's "pump jump" trick in my back pocket, though. I'm curious if that would work. Actually, I just like saying "pump jump"

 

__Jason

[badmotogoozer]

Ok - I spent a ton of time dealing with this about 5yrs ago. What I learned is that it is fuel vaporizing in the line before the fuel pump. Like you say Steve, when you burp this line and allow the liquid to get to the pump intake it will prime and off you go. The vapour gets locked between the closed petcock and the pump (off), and is created by the line's close proximity to the head. Rerouting the lines helped but I still had issues with it. I ran some aircraft/racing fireproof insulated hose sleeve (Firesleeve @ Summit) over this line from petcock to pump. Never had a problem since.

 

My theory is that as long as you keep the fuel in liquid form at the pump inlet it doesn't matter if there is or isn't vapour in the pump, it will still prime. Like I say, five years without forced rest intervals.

 

I sent some to a few members years ago - anyone else using it? Nicola @ Brital bought my extra (I had bought enough to do every line on the bike...) and did the same thing to every bike that came into the shop with the VapLok issue. He says it works.

 

Steve _ I'll let you know if I still have a bit of it around. 50/50 shot of me finding it as I've got motors apart everywhere at the momment.

 

cheers,

[nose2wind]

Was your pump on the top or bottom? Where is it now? Petcock to pump is where I have been burping. Sooo many opinions.

 

A little clarification. My pump was located on the side of the frame (factory position). I tried moving the fuel line off the cylinder head no difference. I changed to the manual petcock (thinking it might burp itself) no luck. Finally thought why not move the pump further away from the heat. It was an easy swap. Haven't had a recurrance in years. Look at the pics and write up.

 

D

 

This doesn't explain why some have the problem and others don't. I wondered if it is a symptom of a weak but still functional pump. The premise being that a strong pump can suck the vapor through but the weak pump has a problem. Just a thought?

[nose2wind]

 

Let's continue the discussion from this picture, regardless of what is left and right on a real bike. Where do you burp?

 

Nice picture. This is not how my bike came from the factory.

 

This is how it is now.

 

d

[badmotogoozer]

No matter how good your pump is it will not pump air, at least not in a system that also contains fluid. Air/vapour is compressible, fluid is not. All the pump does is compress the air, not move it through the fluid and out.

[raz]

FWIW: My Sporti arrangement, perhaps somewhat similar to a Tenni, is like this: the pump is located in front of the subframe. Apart from that the pump itself is not heated by the cylinders, the routing probably encourages vapor and air to go up the (manual) petcock. In the picture from the V11 WHB, the routing seem to trap vapour and air at a higher point than the petcock.

 

I've never heard of a Sporti with vapour lock, has anyone had it on a Tenni?

[Steve G.]

No matter how good your pump is it will not pump air, at least not in a system that also contains fluid. Air/vapour is compressible, fluid is not. All the pump does is compress the air, not move it through the fluid and out.

 

 

This most probably explains the strange gurgling cavitation sounds my pump emits when this situation arises.

You say this insulator is made by Summit? So I could in theory get it from Lordco? [local auto parts store with drag race following].

Steve

[badmotogoozer]

Yeah, you could try Lordco - I found it out at the airport (Lindair service desk IIRC). I had a look last night but I think I gave it all to Nicola a few years ago.

 

It's good stuff - really thick insulation. I think you could lie it against the head and not have a problem.

 

Aeroquip Firesleeve http://store.summitracing.com/egnsearch.as...k=KeywordSearch

 

I don't remember the size... I'll have to look if there is a visible # on the sleeve as they don't give any ID sizing in the Summit catalog. Lindair sold it by the foot, Summit you have to buy 5ft. You only need a foot of it.

 

here's another that has ID sizes http://www.hosexpress.com/hydraulic/accessories/624.htm

 

cheers,

[al_roethlisberger]

You can get the insulation from your local "hot rod" shop, as many engine customizers use the shielding. The aluminized shielding is sold in sewn tubes and flat sheets, and even a "kit" for shielding a starter or fuel pump. It really isn't very expensive.

 

Another source is "Summit Racing" which you can find online.

 

 

I relocated my pump on top of the spine and shielded all lines, pump, and filter and seemed to eliminate the vapor lock. But my original 2002 tank developed a defect soon after and I replaced it with a 2003 model before I really had a chance to test it long term.

 

But based on the comments by bad, I suspect using the shielding alone may help most people. I'd give it a try first, as it only takes a few minutes to install.

 

 

Another field solution might be to install a purge valve in the supply line. You could then open this valve in the field during a VL event, and purge vapor and fuel onto the ground to clear the line. This would simplify the otherwise irritating problem of breaking out some tools to remove the supply line from the petcock. Just a thought.

 

Al