Venting problems 650G

[roscoe G coltrane]

OK here's what I got. I seem to have a venting problem on my 82 650G Itook the cap off and cleaned it and the ball rattles and there wasn't any sign of crud or blockage. The top of the cap is square with a triangle, I'm assuming it has to be pointing towards the front of the bike. am I correct?
I also saw an empty hose connection between #1 and 2 carbs, so I put a
length of leftover 5/16 fuel line that I had and blew into it and I can hear fuel bubbling in the tank, so I'm assuming its a bowl vent also. is that right? after all this it still acts like its not venting right. I can start off ok, but in the same amount of time(3 or 4 min) it starts bogging down to about 40mph no matter what you do. then if you keep it pegged, it will slowly rise back up to normal speed. if you pull in the clutch it will rev up fine, let it out and it just bogs down to almost nothing. it seems to do this in cycles which leads me to beleive its still some kind of venting issue.
oh yea, the petcock is brand new oem from Z1. anybody got any ideas?

[duaneage]

Sounds like dirty carbs.

Could be floats are stuck closed.
Clogged main well.
Stuck slides (those things with the needles on them)
Dirty air filter ( like Katrina levels of dirt )
Dirty inlet screens. There are screens on each arbe where the fuel enters the bowl. If these get sludged or dirty no gasoline will flow.

And of course we have the float level to check. Should be 22mm I think, check your manual (you do have a manual, yes?)

Another test is to drain the fuel from each carb into a baby food jar and see how much comes out. Looking at the jar you should see enough gas to fill those shiny bowls. Then spray carb cleaner down the fuel line and wash all the mud out of the carb until it runs clean.

Put the screws back in and do a 70 foot burnout on your street. After you get out of jail for that take the bike out for a ride before your license is suspended and see what happens.

[roscoe G coltrane]

Thanks for the help Duaneage, I don't think its my air filter its brand new.
about that test, do you do 1 carb at a time?what would happen if I spayed carb cleaner down the bowl vent hoses? I thought about taking off the vaccum hose on the petcock and sticking it in a can of seafoam. you reckon that would work? it does on cars, or so it says on the can. also, can you tell me what way the triangle is supposed to be pointing on the gas cap? nobody else seems to have any answers. thanks again, roscoe

[Guest]

The arrow faces towards the front of the bike. I had the same symptoms and it was the petcock.

[duaneage]

If the petcock is brand new there should be no issues with it, as long as the tube from #2 to the petcock is connected and not leaking,.

I would send carb cleaner spray down the fuel line into the carbs. open the bowl drains and either usea rag or some other container to catch what comes out. Flush them out and see what happens

[Tom MLC]

If the bike has been sitting for a long time, you should rebuild those carbs. Spraying carb cleaner into them is a good idea, but is only a half-measure. Disect the carbs, replace all o-rings, blow out all the passages with compressed air, clean all the tiny passages with a strand from a wire brush.

Are you using a fuel filter? Replace it, if you don't know it's history.

The vacuum line from the petcock goes to the #3 carb on my bike. The brass nipple on #2 & #4 carbs are float vents. I recommend you leave these hoses off. If the hose is in the wind while you ride, air pressure will inhibit the venting affect.

Finally, the vent from the tank float unit should be clear of obstructions. On my GS1100 I found a spider cocoon inside. The bike had been sitting in a garage for 5 years. All sorts of critters had made a home on this bike!

[duaneage]

If the bike has been sitting for a long time, you should rebuild those carbs. Spraying carb cleaner into them is a good idea, but is only a half-measure. Disect the carbs, replace all o-rings, blow out all the passages with compressed air, clean all the tiny passages with a strand from a wire brush.


Finally, the vent from the tank float unit should be clear of obstructions. On my GS1100 I found a spider cocoon inside. The bike had been sitting in a garage for 5 years. All sorts of critters had made a home on this bike!

Rebuilding carbs is a big job, not everyone is up to it and in many cases it is unnecessary to get the bike going. The bulk of the dirt and junk is in the bowls, flushing them can be enough. We all know that perfectly clean carbs with new o rings and other parts is the best thing, but getting there is not easy.
Carbs can be damaged during disassembly ( float towers get broken, jets are frozen and cannot be removed, needles are bent) and that can ruin a set of carbs. I strongly recommend a flush first to see what happens, Imean which is easier to try?

Finally, the vent from the tank float unit should be clear of obstructions. On my GS1100 I found a spider cocoon inside. The bike had been sitting in a garage for 5 years. All sorts of critters had made a home on this bike!

The tube from the float unit of the tank that runs down to the ground is not a vent. It is there solely to drain gas safely to the ground in the event of a gasket failure on the sending unit. Close examination will show that is all it does. My 81', without a fuel gauge, did not have this tube.

[roscoe G coltrane]

I agree Duane,a full disassembly of the carbs is not something I would care to tackle as my working conditions are less than perfect, dirt floors, no really clean work area. yea I've got an air compressor but not a real sanitary enviroment. And no the bike hasn't been sitting a long time not as long as I've owned it. it was running like new up till a week ago. and it still runs now not just the way I want it to.I feel confident that a good bowl flush and some seafoam in the tank will work wonders. Will be picking up some carb cleaner and seafoam on my way into work tonight and jump on it tomorrow when I get up. I'll let you know how it turns out.

[tconroy]

I agree Duane,a full disassembly of the carbs is not something I would care to tackle as my working conditions are less than perfect, dirt floors, no really clean work area. yea I've got an air compressor but not a real sanitary enviroment. And no the bike hasn't been sitting a long time not as long as I've owned it. it was running like new up till a week ago. and it still runs now not just the way I want it to.I feel confident that a good bowl flush and some seafoam in the tank will work wonders. Will be picking up some carb cleaner and seafoam on my way into work tonight and jump on it tomorrow when I get up. I'll let you know how it turns out.

They do have a spray seafoam called DEEP CREEP and it works quick. Pull your fuel line off and spray it down the fuel line into the bowls till the fuel line fills up.It might help to drain the bowls first to get more in there then fire it up!I guarantee it will work quick.

[duaneage]

They do have a spray seafoam called DEEP CREEP and it works quick. Pull your fuel line off and spray it down the fuel line into the bowls till the fuel line fills up.It might help to drain the bowls first to get more in there then fire it up!I guarantee it will work quick.

Most of the business end of the carb is in the bowl. You have two wells, a main jet, and a bunch of little passages. If you can loosen the debris up and then flush it out you might get a miracle/

[roscoe G coltrane]

it is HEALED!!!

Well I finally got to take a decent ride after soaking the bowls overnight then flushing them out from both ends with some deep creep. I dumped half a can of seafoam in the tank for good measure. She ran a little rough at first, but after a few miles it started to come around. it runs better now
than it ever has. you can roll on it in 5th from 30mph with no bog or hesitation. starts good idles good. I couldn't be happier. Now, its time to do that 70 ft. burnout\\/ I'm so glad I didn't have to tear those carbs apart, what a relief!! Thanks for all your help guys, Roscoe