Vapor Lock Question

I've been having a problem on rides(more than 15 miles)where my bike just loses power and dies. sometimes if i wait it'll start up after a while. this was all in cool weather around 50-60 degrees F. but it occurred after putting quite a bit of miles on it.

i'm thinking it may be vapor lock. when i checked the routing of my fuel lines they were pressed up against the engine by the throttle cables. i rerouted the fuel lines but haven't been able to take her for a ride. carbs are clean. i was just wondering is it even possible for me to get vapor lock on a cool day if vac hoses are pressed up against the engine? it was pressed up before it gets to the 3 way connector. so if there was a bubble it would get stuck there because the hoses go down from the connector.

Please go into your profile and modify your signature to reflect your bike year/model. I can't really help technically without knowing what type bike/carbs are being asked about. Thanks

wow quick reply,

It's remotely possible, but not very likely, for it to be vapor lock (and I assume you meant fuel hoses instead of vac). If it happens again, open the fuel cap and see if air gets sucked into the tank, if it does, then your vent is clogged and it's running out of gas. The fact that it only occures after a period of time strongly suggests this is the case.

i actually thought it was a blocked cap vent but there was no hissing sound when i opened it and it didn't help the problem at all

i went for a ride yesterday and never had the same problem. i rode about 4-5 miles going about 30-40 mph(accelerating hard), i was trying to run down the fuel bowls and see if it will stop taking in fuel. it was fine. the idle remains constant after warmup(there is no slight up and down movements).

My bike did the same thing a few years ago. I would ride it normal, and it would run great, but as soon as I got on it, after about 1-3 min, it just bog down. Come to find out my fuel line was weak, and when I got on it, it would suck the fuel line close and would get no gas. This might help. good luck

Post edited by: mysticwolf, at: 2005/10/24 13:05

I have seen a problem on a pickup truck where the fuel pump was mounted on the engine with a fuel filter in the gas tank. Every time it warmed up it would vapor lock.

I suspect the fuel was "stretched" between the filter and the Gas Pump and this reduction in preasure encouraged the fuel to become a gas.

Is it possible that your fuel filter is contributing to your problem?

Spock

i didn't have a fuel filter on the vac hose at that time.

my vac hose was pressed up against the engine near the valve cover. and i did notice it gets very hot.

but i'm not sure if it was hot enough to cause vapor lock. i've sinced moved my fuel lines away from the engine so now they run over top of the carbs. i haven't been able to ride a significant amount of time to really test if its been cured.

Is the vac hose that is against the motor the vac hose for the petcock? If that is the case shorten or reroute that hose. The heat of the motor may soften the hose enough that it collapses and no longer applies vac to the petcock.

yep thats the vac hose from the petcock.

i still haven't been able to ride since its cold and rainy here. i'm hoping that my fuel starvation problems were a result of the hose to close to the engine.

also...

the hose from the petcock goes to 2-3 carbs. where does the 1-4 carbs' hose come from?

nm i'll update after i take it for a longer ride

Post edited by: tarheel365, at: 2005/10/25 12:33

[the hose from the petcock goes to 2-3 carbs. where does the 1-4 carbs' hose come from]

I can't help with your hose hookups. Do you have a FSM or owners manual?