'81GS1100 - starting, idling, getting going problems

[Anonymous]

My bike has stock airbox and carbs, carbs and gas tank are clean, fresh gas, new petcock, all intake boots are new, stator is good, has new battery, and has a new Electrex rectifier.

Problem: The bike won't start reliably and normally and dies when I try to get moving from a normal start.

1. To get the bike started even right after it's warmed up, I have to have the choke on and have the petcock set to prime. If the petcock is on run, it won't start even when the engine is warm.

2. After a minute or so of idling around 2500-3000 rpms, the bike will idle at @1200 rpms after the choke is pushed in and the petcock is moved to run. But, it dies if I then give it any throttle, with or without slowly releasing the clutch.

3. The bike seems to be running lean (some "popping" sounds).

I can't safely drive this sucker until I get this fixed. So, what's the mostly likely problem? Does this sound lke a jetting problem, or could this just be a fuel flow/starvation problem? (ie: the bowls aren't getting filled quickly enough by vacuum)

[moto_dan]

I agree that it sounds like a lean condition. I would check the connection of my vacuum line from petcock to #2 intake. If it is split or not connected the symptoms your describe would exist.

[Anonymous]

I have the exact same problem

I have the exact same problem as the one jhantke described. Any more insight about solutions would be so helpful. Thanks.

[Anonymous]

Check your float height. If it's dying like this even on prime, something is amiss in the carbs, i'd think. Are the spark plugs buring white?

[Anonymous]

I just wanted to lett you know that it is really important that the vaccum line is properly connected. My GSX 400 1981 started to act wierd some days ago, I was really concerned about it. It suddenly wouldn`t start as quick as normal, and also runned rough and had trouble with idling.
I took at quick look on the engine, the vaccum line was loose !

Re-attached it, problem solved !!!)

[Anonymous]

How dumb can a guy get?

...the vacuum hose to carb 2 was disconnected at the carb.

Duh!

[Anonymous]

it seems that so many of us have trouble wiht the vacume line to number 2 carb that we should have an automatic monthly check of the vacume line on the second day of each month or something crazy like that

[moto_dan]

Re: How dumb can a guy get?

...the vacuum hose to carb 2 was disconnected at the carb.

Duh!

Glad you got it fixed. Don't be too hard on yourself, I could write a book on similiar instances in my 37 yrs of messing with bikes.

[Jay B]

Before I changed petcocks and did away with the vac hose I put new hose on there and then shrink wrapped it and quit worrying. I also clamped it on with those little spring clamps to keep it from slipping off.

[Anonymous]

I've clamped that sucker on good!

Now, all my lights have up and died -- no turn signals, no headlight, no brake light,...nuthin'

So, before I post this latest problem, I'm checking that damn vacuum hose (or, whatever the electrical equivalence may be).


Thanks.