Vapor Lock ????

[eddiev]

Hi,
Last night I rode my gs1100gl home from work, a 40 mile trip on the expressway. ABout half way the bike started bogging down as if it was starving for gas. I had about 1/4 tank left and the petcock was on reserve as I always keep it. It progressivly got worse for about 5 miles and finally died. It wouldn't start and I pushed it for about 2 miles. I tried starting it again and it almost turned over but didn't. Pushed somemore, tried again and it started and I rode it 2 miles to a gas station. It was still bogging downbut not as bad. I filled it up and it was fine for the final 10 miles.
ANy ideas. It felta slight boghging down last time I rode home on a cold night but I had topped the tank off then and it never got as bad as last night. Vapor lock, water in tank, bad gas (but it was fine riding in) tank needs vent??????
Thanks.
Eddie V

 

[Anonymous]

Be sure nothing is partially blocking the air intake. maybe it's starving for air insteda of gas. I had a map slide out of the storage tray on a KZ 900, The bike kept bogging worse & worse, till it died graveyard dead. Moved map, all was well. I've got to ask. Why run on reserve all the time, I'm sure there must be a reason.

 

[Anonymous]

I run in reserve because I check my guage every morning. If I'm near 200km on the trip meter if I go get gas. It saves me the trouble of having to fiddle with the petcock in traffic. I do use it when on the highway though, that's where it is important to have one. I bet Eddie does the same thing more or less.

Steve

 

[redliner1973]

Water in gas? doubt it, water is heavier and you will usually have probs just after a fill up. bad cap? could be, does it go shoosh when you open it just after a ride? but sounds to me like crap is on the reserve filter of the petcock. whe your level is higher it goes over it and all is fine, when you get lower in gas it 'runs out' even though there is gas in the tank. waht makes me think of this is the fact that after 2 miles of pushing, the gas had enough time to creep by the 'crap' and get enough fuel to run for aliitle while. then you fill up and all is fine, as the fuel level has once again rien over the 'crap' on the filter. Pull that 'cock out and give it a good lookover, also making sure the diaphram is OK. you can try running in 'prime' if it starts acting up again and see if that changes anything.

 

[eddiev]

Thanks for all the replys. My reserve seems to hold almost 1 1/2 gallons of gas. That's 60 miles. Besides, I have a fuel gauge so I don't really see the need for the reserve. When I first got the bike, the gauge went down to 1/4 tank and it died (100 miles on the tank). I never thought it was out of gas. I thought something else was wrong. It was the max range before reserve. It took less than 3 gallons to fill up. So, I've been just keeping an eye on the gauge. I don't notice an air suction when I remove the gas cap. I was thinking of pulling the cap the next time this happens though. This may be a stupid question but does the tank have to be drained to remove the petcock? Thanks. Eddie V

 

[kz]

This may be a stupid question but does the tank have to be drained to remove the petcock? Thanks. Eddie V

Not if you remove the tank from the bike first and the tank not contains too much gas.

You have also the possibility too just let the gas flow free as you remove the petcock (minimum requirement is that the engine is not hot), but there might be some environmental aspect too that....

 

[Anonymous]

Here's what I'd do just to see if there is a problem with water in the gas tank. First, I would drain the carb bowls and examine the contents into a clean container - not too difficult. If there are any droplets of water there you should be able to see them easilly. If you see any, it may be a good idea to take off the tank, drain it, and remove and clean the fule petcock. It sounds as if a little maintenace is in order.

Steve

 

[jimcor]

Eddie, I had a similar problem with my bike. Turned out to be the petcock.
You might make sure the vacuum operated diaphragm is working properly. You can buy aftermarket rebuild kits for the most popular ones. Hope this helps!

 

[redliner1973]

If your only getting 100 miles before going on reserve, then your petcock is definately bad. It is a whole lot easier to just put on prime and attach a hose from it to a gas jug and drain as much as possible. alot easier if you just take the tank off. This way you can also 'flush and shake' the tank and get all those small 'crap' and rust particulates out.

 

[Dink]

The easiest way to avoid problems with water in fuel is to add a small amount of metholated spirit (1/2 cup) per tank it will do no harm and absorbs any water and allows it to pass through the motor with no ill effects.But I would look at the filters in side the tank on the fuel tap, easier to do if the tank is low and you remove it and lay it on its side, whilst it is off check the diaphram.
Dink

 

[Anonymous]

Dink:
Around here it is a no-no to use Methyl Hydrate because it dries off the cylinder walls. That's what you're talking about right? We usually buy the stuff that says "Gasline antifreeze" just to be safe.

Steve

 

[mdole]

I had the same thing happen to me Sunday on my way home from a toy run. I started home and at about 30 miles late the bike started loosing power and stopped within about a mile. I hit the starter and it tried to fire but acted as if it wasn't getting gas. I spent a 5 or 10 minutes looking things over and the tried it again and it started right up. I rode for another 10 miles and it started loosing power again but I slowed down and it didn't quite die then came back on its own. I have only had the bike a couple of weeks so I'm still finding out what it needs. The petcock had a few other problems so I ordered a new one and will give it a try.

Another possibility is that the vent in the gas cap is plugged and I drew a vacuum in the tank. I don't know if this is a problem with these bikes but I had this happen one a Yamaha XS650 that I had several years ago.

 

[Dink]

Steve, no I am not talking about Methyl Hydrate, I am talking about metho as in alcohol,I was just trying to be precise because of the language barrier between Australia and the US ,cause you guys talk funny ya know.
Dink

 

[moto_dan]

Steve, no I am not talking about Methyl Hydrate, I am talking about metho as in alcohol,I was just trying to be precise because of the language barrier between Australia and the US ,cause you guys talk funny ya know.
Dink

Steve is from eastern Canada not the USA :evil: