Vapor lock at 101 degrees F ?

[Redeye]

Whenever it is 101 outside, I seem to have momentary fuel vapor problems.  I think the layout of the engine is the main problem, where the carbs and fuel lines are dangled in "death valley" where they get radiated heat from the top of the engine.  For carbureted cars, people used to add sheet metal shields to reflect radiated heat away from the fuel lines, gascolator, filter, fuel pump etc.

Has anybody measured temperatures on fuel line stuff?  I am thinking of running some experiments, and measuring temps down there, with an without a heat shield on top of the engine.  Instrumentation would be an inside/outside thermometer - using the wired probe taped to various things like the inline fuel filter.  The next problem is, I have to figure out a heat shield that can be ripped off while riding, so I can get a true-treatment-effect.

[Ricky-D]

Vapor lock is a thing of the past.

It usually related to the fuel pump not pumping gas to the carburetor because of the effect of the heat upon the gasoline causing it to cavitate within the pump mechanism.

Trying to apply that to a motorcycle where the fuel is gravity supplied won't work.

If you have fuel delivery problems, look elsewhere for you are wasting your time with this hypothesis.

***

[98valk]

I agree with R-D, I think your problem is elsewhere.

Q.  Does ethanol cause vapor lock?

A.  The vapor pressure of gasoline is set by law – and is lower in the spring and summer than in the fall and winter.  Vapor lock usually occurs when a winter grade of gasoline formulated for cold weather starts is used under summer-like conditions.  Additionally, all major auto manufacturers now have in-tank fuel pumps, which are not subject to vapor lock like the older in-line fuel pumps.
http://www.gasamerica.com/E10.asp


Will ethanol-blended fuel cause vapor lock?
Vapor pressure specifications of gasoline continue to be lowered by state and federal statute, virtually eliminating the vapor lock problems that were reported in the past. Additionally, all major auto manufacturers now have in-tank fuel pumps, which are not subject to vapor lock like the older in-line fuel pumps.
http://www.flexiblefuelvehicleclub.org/faqs.asp

[Jess Tolbirt]

put clothes pins on it,, that'll keep it from vapor locking,,,

[sugerbear]

try taking off the "quick disconnect"

[R J]

Take da dang in line fuel filter off of it.

Can't explain why, but when I had my in-line filter, I used to have fuel flow  problems.

Took it off and it hasn't failed since. That was like 124K miles ago it was removed.

[Patrick]

I haven't experienced the problem you're having on the Valk, but, vapor lock certainly happens with gravity feed fuel systems especially today with this crap ethanol .. Switching to non-ethanol in the warm months helps.. I've dealt with this issue for many years on many different vehicles.. The easiest thing I've found is wrapping the steel fuel lines with flex line, but, that won't help the Valk.. I have 2 old cars with gravity feed that don't like ethanol fuel in this weather and will vapor lock at times, marine fuel helps..
So, what makes you think you have vapor lock ?? How does it act ?? If the pair valve assembly has been removed, the fan should push more air thru that area..

[Redeye]

But, RJ, the fuel filter only has three years on it.  

[Redeye]

I agree, Patrick. This impossible little problem shows up in the old car forums having gravify-feed fuel.  E90 fuel sucks for vapor lock.  The winter E90 used in warm weather sucks even more. 

[Gear Jammer]

Take da dang in line fuel filter off of it.

Can't explain why, but when I had my in-line filter, I used to have fuel flow  problems.

Took it off and it hasn't failed since. That was like 124K miles ago it was removed.

Added the fuel filter you recommended Rich when I installed the quick disconnect, but quickly found I had fuel starvation like RJ mentions    .  It took me awhile to diagnose what was going on, but I too removed the filter, and the problem "went away"  

[Farther]

I agree, Patrick. This impossible little problem shows up in the old car forums having gravify-feed fuel.  E90 fuel sucks for vapor lock.  The winter E90 used in warm weather sucks even more. 

If you trying to use E90 in an older vehicle, it will indeed cause some problems.  I suggest you use E10 instead.

[Bobbo]

Here's a good write-up about gasoline and ethanol regarding vapor lock:

http://www.txideafarm.com/ethanol_fuel_properties_and_data.pdf

[Tropic traveler]

Vapor lock? 101 degrees? Fuel filter a problem?

I have run this fuel filter for the last 3 years & over 30,000 miles with no vapor lock.


I did have some early "need to go to reserve" episodes but not for a long while. It's most always what you guys call hot here in Florida but never any vapor lock. I did do a desmog & do not have any chrome transmission covers to hold in any heat so maybe that helps.

[Daniel Meyer]

I'd suspect mods (quick-connect, in-line, longer fuel line) or vent line issues.

I've had the Valk in tremendous heat...horrific heat...do most of the time in fact...no issues. Not even a hint of any possibility of issues. This machine likes to play in the heat.

[RP#62]

If it was the temperature, then mine wouldn't run from mid May thru the end of September.
-RP

[X Ring]

I'll admit that the combination of a quick disconnect and fuel filter caused a fuel starvation issue at highway speeds.  Removed the quick disconnect and haven't had a problem since.

Marty

[Patrick]

I didn't notice any mention of a quick-connect, just a filter.. Some have had issues with the connect.. I think most have found they left the fuel line a bit too long.. I haven't had any issues with a filter, I prefer running a filter.. I thought he was having vapor-lock issues, which means hot-soak/fuel boiling while the bike was sitting.

[98valk]

I have had no problems with the quick-disconnect, however I also installed it so that is horizontal to the engine and not verticle as in the instructions.

[Redeye]

Yes, Tropic Traveler, the transmission covers and also engine hanger covers on some bikes seem to have an effect on heat buildup.  I saw a post a while back here, and the guy ended up removing his new hanger covers to defeat his equally-new vapor lock problem.  The radiation effect is called emissivity.  Metals let too much heat fly out as radiation, and radiation gets to travel across a windy gap to the fuel line without losing energy. That's just not fair - the wind isn't doing its job.  The hanger covers radiate their heat right back at the fuel line.  By the same logic a metal fuel filter, or a metal fuel pump on an old car, radiates some of its heat inside itself, cooking the fuel inside there (promoting a vapor bubble).  

The fix according to some insulation experts is to cover the metal heat source with a black body  http://www.dyplastproducts.com/polyisocyanurate_bunstock/pdf/Insulation_Fundamentals_Emissivity.pdf So a metal fuel filter needs to be encapsulated with a black body.  The carburetors themselves should have a black body between them and the top of the engine block.  The fuel line has around 95% emissivity, so it is not an issue.  Engine hanger trim should be lined inside with a black body.

According to the chart on this website, cheap ordinary roofing felt installed on the top of the engine would defeat 95% of the heat radiating from the top of the block, allowing the cool 101 degree air to take most of the 200 degree heat away.  Too bad roofing materials stink and are somewhat flammable - I'm not putting that on top of my engine!  So, I'm looking for flexible black fireproof non-roofing felt.  Something that handles like a hand towel, and about the same size and shape too.

[zimmerleemark]

gas cap can get dirty and cause these symptoms as well. at least on the goldwing. cleaned gas cap with carb cleaner and no more problems

mark

[FLAVALK]

Vapor lock? 101 degrees? Fuel filter a problem?

I have run this fuel filter for the last 3 years & over 30,000 miles with no vapor lock.


I did have some early "need to go to reserve" episodes but not for a long while. It's most always what you guys call hot here in Florida but never any vapor lock. I did do a desmog & do not have any chrome transmission covers to hold in any heat so maybe that helps.

I've run the same (or very similar) filter for at least two years in some hot-assed weather without a problem

[bigguy]

I agree, Patrick. This impossible little problem shows up in the old car forums having gravify-feed fuel.  E90 fuel sucks for vapor lock.  The winter E90 used in warm weather sucks even more. 

If you trying to use E90 in an older vehicle, it will indeed cause some problems.  I suggest you use E10 instead.

 

[Redeye]

That sounds reasonable for a Wing.  Valk tank has a dedicated tank vent hose.  My vapor lock happens at 101 F or higher, after cruising at freeway speed, then slowing down to zero mph for some traffic congestion.  Aside from being impossible for gravity feed fuel delivery, it seems to be temperature related.  I think I'm using E10 fuel like everybody else, not E90  .  I wonder why a full desmog seems to reduce the vapor lock.  I keep hearing this, like in FLAVALK's post.  Maybe the Reed Valve assemblies get hot while sitting and idling, so when they get removed, there is less heat next to the carbs or maybe better air flow.  I need to measure an bunch of temperatures - see what is going on in Death Valley on the Interstate model. 

[Bobbo]

Behind the radiator there should be a plastic deflector shield.  This is to deflect the hot air around the carb banks.  Is this still on your bike?