One wet cyclinder

[yellow]

Got my Intake O-rings in from a friendly GS'r (alright enough sappy crap) and put them in today. She idles a lot better and seems to let me let the choke down sooner after starting her up. Also noticed that the #2 cyclinder was actually warming up at idle. WOW. Still has the hesitation around 2800-3000rpms before she trudges thru it and then is smooth and responsive. So that is the same. Now....

....the problem:

Took off intake boots to install o-rings and was cleaning mating surface and noticed that the #2 cylinder was filled with fuel. Soaked up the fuel finished my job and observed the above.....Now

WHY WAS THAT ONE CYLINDER FILLED WITH FUEL? This is the same cylinder that had the choke circuit fuel pick-up tube issue. It could have all gotten in there when I removed the carbs....(no other cylinder was wet) Or it was in there from before....any ideas?

Thanks again - andy

[scotty]

seems related to vacum petcock at first glance

[yellow]

Scotty - Why would it only be that one cylinder #2 then? The petcock does work and is not perpetually open....are you thinking that if it was in a "prime" state (vacuum petcocks do not have prime) if there was an issue with the diaphragm then it might fill up the #2 cyclinder?

[arveejay]

If your petcock sticks open, or has a problem with it the gas will not shut off. It is probably running thru the vacuum hose into number 2 carb and straight thru. It's also deluting your oil, don't run engine without oil and filter change. You might also have the #2 float valve out of adjustment and fuel just runs straight thru. When I bought my 750 and got her going I filled the tank and parked it for the night. Next day 1/2 tank of fuel was in the crankcase. Petcock diaphram had a dry rot crack in it. New Suzuki petcock and troubles are over for another 20 years.

[flyingace]

In theory, the #2 carb should not flood if the float/needle/seat are operational. But come to think of it, is that necessarily true? Can the pressure from a full tank push gas thru a working valve?

[scotty]

In theory, the #2 carb should not flood if the float/needle/seat are operational. But come to think of it, is that necessarily true? Can the pressure from a full tank push gas thru a working valve?

So many of us have proven that theory wrong even though it is correct lol lol--valves stick sometimes

[scotty]

Gee we are not being helpfull here.

Remove the hose that goes from the petcock to the #2 carb. It is a vacum hose--usually the smaller one. Sniff or inspect. Absolutely no evidence of gas should exist in the tube.

[yellow]

I will try that and get back to you. work tomorrow (24hr shift) so it'll be on friday...thanks for the suggestion

Gee we are not being helpfull here.

Remove the hose that goes from the petcock to the #2 carb. It is a vacum hose--usually the smaller one. Sniff or inspect. Absolutely no evidence of gas should exist in the tube.

[yellow]

My "oil" level has not changed at all and fuel does not seem to be going anywhere. Petcock is not leaking when tank off...Might it still be getting thru?

If your petcock sticks open, or has a problem with it the gas will not shut off. It is probably running thru the vacuum hose into number 2 carb and straight thru. It's also deluting your oil, don't run engine without oil and filter change. You might also have the #2 float valve out of adjustment and fuel just runs straight thru. When I bought my 750 and got her going I filled the tank and parked it for the night. Next day 1/2 tank of fuel was in the crankcase. Petcock diaphram had a dry rot crack in it. New Suzuki petcock and troubles are over for another 20 years.

[yellow]

Update

1. Oil levels where unchanged since January of this year.

2. Petcock does not leak.

3. No physical evidence of fuel in vacuum tube.

4. Vacuum tube does smell like gas. I did smell in that area before removing tube from petcock - no gas. Shoved tube up trusty nare and lo and behold a smidgen of gas scent.

5. Changed oil. Going to closely monitor levels.

SUGGESTIONS PLEASE........Not sure what to do. This will be my commuter soon and need to get her reliable.

Thanks

[arveejay]

1 more test for the petcock, The littlest hose is the vacuum hose, with the vac hose attached to the petcock suck on that hose. You should be able to pull and maintain a vacuum as felt with your tongue. If the hose will stick to your tongue indefinately, then it won't leak thru the vac hose. With the petcock lever pointing straight down and the other petcock hose (gas) draining into a catch can or a gas can, suck the vac hose. It should release fuel when a vacuum is met. When you release the vacuum on the petcock the fuel should quit flowing pretty instantaniously, except what would still be in the hose. Do that 6-8 times and assure the gas flow is shutting off for sure. If the petcock tests ok the about the only other thing it could be is fuel getting past your float valves or around them from a flat O ring. Check the brass part of valve for dents or imperfections which would stop the needle from seating. Check the someone before you didn't partially distort the shape of the valve from pulling out with pliers and this will stop the needle from moving freely in the valves, it should not hangup at all. Check the needle for wear. Remove the valve and if the O ring is flat, replace it. Set the floats in the middle of acceptable range as specified in you book. If you parking on side stand gravity would try to leak the fuel from right carb to the left carb as it is sitting lower due to the leaning. See if it does it on the centerstand. If none if this helps, we'll try something else.

[yellow]

Eureka!

Arveejay - back to basics when there is a problem...good thinkin'

So I used a syringe instead of my tongue, hopefully the results will still hold. My vacuum petcock when under vacuum flows fuel nicely. It however flows fuel poorly, yet still flows when not under vacuum. i.e. leaky. Looks like my ASSumption was completely wrong. Time to rebuild.

WHERE DOES ONE GET ONE OF THE REBUILD KITS? Thanks again for the help

Sincerely - andy

1 more test for the petcock, The littlest hose is the vacuum hose, with the vac hose attached to the petcock suck on that hose. You should be able to pull and maintain a vacuum as felt with your tongue. If the hose will stick to your tongue indefinately, then it won't leak thru the vac hose. With the petcock lever pointing straight down and the other petcock hose (gas) draining into a catch can or a gas can, suck the vac hose. It should release fuel when a vacuum is met. When you release the vacuum on the petcock the fuel should quit flowing pretty instantaniously, except what would still be in the hose. Do that 6-8 times and assure the gas flow is shutting off for sure. If the petcock tests ok the about the only other thing it could be is fuel getting past your float valves or around them from a flat O ring. Check the brass part of valve for dents or imperfections which would stop the needle from seating. Check the someone before you didn't partially distort the shape of the valve from pulling out with pliers and this will stop the needle from moving freely in the valves, it should not hangup at all. Check the needle for wear. Remove the valve and if the O ring is flat, replace it. Set the floats in the middle of acceptable range as specified in you book. If you parking on side stand gravity would try to leak the fuel from right carb to the left carb as it is sitting lower due to the leaning. See if it does it on the centerstand. If none if this helps, we'll try something else.

[dietcokeking]

Instead of a rebuild kit, you can buy a new petcock pretty cheaply. They were about $45 on Ebay the last time I checked.

[Giblet]

Scotty is right. I have personally proved the fallability of the needle/seat valve theory. My GK was fouling the #2 plug constantly and gas mileage was all over the place. Bought a new Suzuki petcock and all was OK for about a year. Problem (probably the diaphram) came back. Installed a new Pingle valve and problem solved. Vacuum operated petcock was a good idea in theory but unfortunately when the problem is unnoticed bad stuff can happen. Ditch the Suzuki petcock, get some brand of manual petcock (make sure it has an actual reserve function, the Pingle does) and that problem is gone. Pay me now, or pay me later. If it was a great idea, they'd still be making bikes with vacuum petcocks.

[arveejay]

Arveejay - back to basics when there is a problem...good thinkin'

So I used a syringe instead of my tongue, hopefully the results will still hold. My vacuum petcock when under vacuum flows fuel nicely. It however flows fuel poorly, yet still flows when not under vacuum. i.e. leaky. Looks like my ASSumption was completely wrong. Time to rebuild.

WHERE DOES ONE GET ONE OF THE REBUILD KITS? Thanks again for the help

Sincerely - andy

Good, you found the problem, now how to correct it.
Folks here have had problems with the rebuild kits, the O Rings are the wrong size and don't shutl off fuel completely or something like that. I buy new petcocks thru www.bikebandit.com I personally wouldn't consider anything but factory replacement petcock but others here like the Pingel replacements. It really comes down to remembering to shut the valve off everytime you shut the bike off and turning it back on each time you ride. If your float valves are shutting the fuel flow off as they should, forgetting to turn the petcock off probably wouldn't be a big deal but if you have the slightest seepage and forget to shut the fuel off your going to get fuel in the oil which is NOT GOOD. My aged memory would cause me grief with the valve, that's why I go Vacuum original.