Stalling @ 70-80mph

[SOCKinside]

GS1000E, After riding for 5 miles, at a steady 70-80 mph it starts to miss fire, starts popping and power loss, if i pull over and let it idle, bike starts to run perfect again, im not sure if its a floater prob, any ideas

[hampshirehog]

Sounds like it may be a fuel line / fuel tap issue though 5 miles is a long way for it to run ok at that speed. Have you cleaned everything from your tank through the tap, through the carbs to your engine?

[MisterCinders]

Does it stall at all throttle positions? Could be a bad AFR in the needle or main jetting.

Otherwise, I think the hog's fuel starvation may be the answer. Try to recreate the problem. Then pull over and loosen the gas cap and see if it happens again. With the loose cap, you can rule out vacuum lock on the fuel tank at least.

[1980GS1000E]

Fuel flow. Either the gas cap as previously suggested or fuel delivery to carbs. Is there a fuel filter fitted? That can impede flow. Carb vent tubes ok?

[trevor]

Could it not be the petcock guys?

[SOCKinside]

-"hampshirehog", the lines are clean, carbs i dont know? the might just be dirty, just got the bike a month ago.

-"MisterCinders" ill try that next time, but the thing is that when i actually pull over,its starts riding perfect again, maybe ill try riding with no gas cap on? until once again i keep the throttle steady at a certain RPM, and after a while it starts again, but in the city, with all the stops and goes, it NEVER happens.

[SOCKinside]

one of my vacuum ports of my carbs is connected to the petcock actually, can that be a prob, maybe i can try disconecting it while it happens?

[SqDancerLynn1]

If your petcock has a lever turn it to prime and try it.. I would also clean the gas cap as suggested..

[1980GS1000E]

one of my vacuum ports of my carbs is connected to the petcock actually, can that be a prob, maybe i can try disconecting it while it happens?

That line is supposed to be there. It sends engine vacuum to the petcock which tells the petcock to flow fuel. The petcock stops fuel flow if the vacuum isn't present.

[81ZUKI75]

Pressurizing fuel bowls?

This only applies if you have lines attached to your fuel rail vents and I offer this as an example of the simple things...

On my 750E, I noticed stumbling when I moved my right foot forward on the pegs while running at highway speeds (normal position is on the balls of my feet)...WTF?

I discovered that the vent line on the right side was routed such that when I placed my foot in just the right spot, air was forced into the tube, effectivly pressurizeing the carb bowls. I tucked the hoses back behind the clutch cover close in to the frame and have not had the issue re-occur.

[MisterCinders]

one of my vacuum ports of my carbs is connected to the petcock actually, can that be a prob, maybe i can try disconecting it while it happens?

Don't disconnect it at 70 MPH. You will add a load of air to that cylinder and kill your fuel supply.

Not something to do at highway speeds.

[mrbill5491]

one of my vacuum ports of my carbs is connected to the petcock actually, can that be a prob, maybe i can try disconecting it while it happens?

That was what was happening to my bike, turns out it would loose vacuum to the petcock and fuel would be shut off. Check your carb boots, vacuum line from the #2 carb to the petcock and the petcock itself. If you have a filter might want to take it off, filters tend to restrict the gravity fed fuel flow. Just a process of elimination to discover what the problem is.

[Big T]

, vacuum line from the #2 carb to the petcock and the petcock itself. If you have a filter might want to take it off, filters tend to restrict the gravity fed fuel flow. Just a process of elimination to discover what the problem is.

Depends on what year GS1000 he has, early ones have the vacuum port on #3 carb

SOCK, since you asking lots of questions, update your signature with you bike so we don't have to guess

[SOCKinside]

view of the vacuum port to the tank

i guess its #2 carb? not sure

[SOCKinside]

i rode in to work today, and it started stalling again, it was like if 2 cylinders were to stop working, i heard the carbs back firing, and poping but yet again i pull over the side of the road and all of a sudden, back to normal, i think its a carb prob!