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Discussion Starter · #1 ·
What do you guys do for vapor lock? Do we have room under the tank for one of those plates for the carb? I got stuck in trafic for about 1,5 hours and I vapor locked :( By the way my fuel lines are fine, it the carb that is getting hot.
 

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While you are on the subject of vapor lock, would someone please describe it fully. I don't think that I have ever experienced it and I would like to know what to expect and understand why it happens.


Thanks,

Hoss
 

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LaMonsterV8 said:
What do you guys do for vapor lock? Do we have room under the tank for one of those plates for the carb? I got stuck in trafic for about 1,5 hours and I vapor locked :( By the way my fuel lines are fine, it the carb that is getting hot.
Lamont

If you install a 1/2" plate for the NOS you need to cut away or bend in the frame in so the linkage will clear, so if you install a plate you will need to do the same thing. I have had the same thing happen but not to the point the bike would not run, not very good, but could at least get out of the way. Mine would only last for a short while.

What causes vapor lock is when the gas boils in the line, after the fuel pump, and turns into vapor. Sounds like it is in Lamont's Carb but normally it is in the lines. In most cases the problems is caused by having the lines to close to hot engine parts like the heads, manifold and anything else that is hot.

Adrian
 

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Vapor lock happens when the atomized fuel in the intake manifold evaporates before it makes it to the combustion chamber. This happens when the fuel gets too hot in the carb. Usually caused by a restricted filter or the float level being too low. The carb actually needs a certian volume of fuel inside to stay cool. too little fuel and it basically boils and then evaporates instantly when atomized for combustion. Basically you just run out of gas with a full tank. Makes me wonder..... Just how hot does your bike run Lamont?? I know I have sat in traffic for a long time at 100 degrees and never had a problem. Never seen engine temp over 200 either. more like 195.
 

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Right on the money as always Adrian...... hot gas is the culprit. Well put.
 

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Lamont,
You might be experiencing percolation. Which is basically what TJ and Adrian are saying. It's when the gas in the carb bowl starts to percolate, or, basically, boil. It can either evaporate the fuel, or spill out the bowl vents and flood the motor.
I noticed my carb would get very hot after idleing for a time. When I rebuilt the carb, in the kit there was a manifold to carb gasket that is 1/4 inch thick. It's an "open" gasket. There aren't individual holes for the primary and secondary throttle plates. In the kit there are also gaskets with the holes. I suppose you could use both if you want. I only used the "open" 1/4" gasket, and it runs great. It fit with no clearance problems, and the carb runs much cooler. I used the Edlebrock rebuild kit # EDL-1920. Got it from Summit. Hope this helps.........Don B
 

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Discussion Starter · #7 ·
Looks like 1/4" is about as tall as I can go without mods, I'll try that.
As far as temp goes my bike never showed over 180 degrees and I have all my fuel lines tied up to the frame so I don't think that was it. I'm thinking about another fan right where the fuel pump use to mount in front. That might do it too. Got any ideas on that?
 

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Lamont,
I suppose getting more air circulating might work, but with the radiator fan blowing all that hot air back at the motor, and sitting still in traffic, I wonder if another fan would actually do anything. I know when I'm stuck sitting in one place for a while, I just shut it down. Good luck!
 

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Discussion Starter · #9 ·
Boss Man said:
Lamont,
I suppose getting more air circulating might work, but with the radiator fan blowing all that hot air back at the motor, and sitting still in traffic, I wonder if another fan would actually do anything. I know when I'm stuck sitting in one place for a while, I just shut it down. Good luck!
You may be right but if I have just a little bit of ram air I never have a problem so I'm thinking maybe passing some air through there would help. I guess there's only one way to find out. ;)
 

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Remember Daytona and I said I thought my bike was doing the same thing - After running for awhile and the engine was HOT each time I would try and "hammer it" it would cough real bad. Well I moved my fuel lines when I got home and got them away from the manifold ... so far no more "cough" but the ambient temps are not as high as FL either :) Your problem is a little more difficult being the lock is occuring at the carb :(

I think if you have a 1/4" space to work with then I would add a 1/4" spacer and get the carb a little higher ... hopefully the extra space will do the trick.

I wonder why they are all different? Mine I understand because the lines were laying on the manifold in spots (I will change all the fuel lines out next chance). I am assuming the carbs are all in the same position .... model year would be dependent as to airflow under the tank but space above manifold would all be the same. Wonder why some have problems and other not :?
 

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Hi Don!
How ya doin? Looks like the riding season is finally here. Had some nice warm days here for a change. Even got the Boss out a few times. I think I'll be needing that new rear tire sooner than I thought! Ha Ha!
As for your question about why some do and some don't.......Who knows? But it sure keeps things interesting doesn't it!!
Hope you are well. Are you planning on going to Stamfords open house in July? :D ..........Don B
 

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Don,

Another thing that helps eliminate "vapor lock" is higher fuel pressure and more volume capacity. It keeps relatively cool fuel forced into the lines and helps to stop the 'vapor' from forming. The stock pumps are a little weak in the pressure area and under hard acceleration they are on the edge for being able to supply enough fuel...my small block consistantly would starve on the top end in first....I could not pull over 5500 rpm without it running out of fuel......once we changed to the bigger volume pumps, the problem went away.

Tim
 

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Boss Man said:
Hi Don!
How ya doin? Looks like the riding season is finally here. Had some nice warm days here for a change. Even got the Boss out a few times. I think I'll be needing that new rear tire sooner than I thought! Ha Ha!
As for your question about why some do and some don't.......Who knows? But it sure keeps things interesting doesn't it!!
Hope you are well. Are you planning on going to Stamfords open house in July? :D ..........Don B
Don
FINALLY good weather! New rear tire huh
That new converter IS awesome!

Everything is going great, been riding myself. My miles have been divided between the Boss and the Capo. Capo gets the "not so great" days to ride - windshield helps a great deal in rain and cold and the Boss gets the perfect days - as it should! The Valk ... well it gets a cold/dark corner of the garage still attached to a battery tender. I guess I will have to move all the bikes out so I can get it out to run the Stabil out fo the tank! I most definantly want to go to the Stamford open house! Keep me posted on dates/times, probably spend the weekend down there. I am sure I will be down before July - I'll be needing new rubber too before then
Don't tell Kim :wink:

Don


Grumpy said:
Don,

Another thing that helps eliminate "vapor lock" is higher fuel pressure and more volume capacity. It keeps relatively cool fuel forced into the lines and helps to stop the 'vapor' from forming. The stock pumps are a little weak in the pressure area and under hard acceleration they are on the edge for being able to supply enough fuel...my small block consistantly would starve on the top end in first....I could not pull over 5500 rpm without it running out of fuel......once we changed to the bigger volume pumps, the problem went away.

Tim
Tim
I was watching the other thread from Hoss about his fuel pump. I was getting the idea the stock pump is not the best choice. I will probably swap to a Carter like you, Wag and others are running. I hate the feeling of wacking the throttle and "cough. cough, sputter, cough ... GO" :( The swap is easy enough and if that is all it takes - GREAT :D

Don
 
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