A few questions on a non running 1981 GS 1000GL

[mazza_gs1000]

Can the bike run without the air cleaner attached?

With the Fuel cock full back, it's "prime", right? And with it down, it's "run," right?

For some reason the bike won't stay running. I thought that if the air cleaner was off I could make some adjustments to the carb (if any could be made).


Thanks,

Michael

[Dave8338]

Will it run...yes, sort of. Will it run correctly, no, not at all. WAAAAYYYY to lean without a filter and any adjustments that you do make, will be wrong, once things are back together the way they're supposed to be.

If by back with the petcock lever, you mean that the handel is point back towards the seat, then yes, that is prime. Down is ON / RUN and forward is OFF.

[ddaniels]

Yes, any adjustments you make to the carbs should be done with everything on that's going to be on. And you definitely need some kind of filter.

[Steve]

If by back with the petcock lever, you mean that the handel is point back towards the seat, then yes, that is prime. Down is ON / RUN and forward is OFF.

Not quite, there, Dave.

Handle pointing back is PRIme.
Handle pointing down is RUN.
Handle pointing forward is REServe.

Vacuum from the running engine will turn on the petcock when it is in the RUN and RES positions.
Fuel will flow freely when the petcock is in the PRI position.

There are very few, if any, adjustments you can make to the carb with the airbox off that you can't make with it on, so there is no advantage to having it off. Most bikes will start and idle with the airbox off, but won't go much above that. If, for some reason, you absolutely HAVE to have the airbox off, take a shop rag, double it over, then drape it over the carb intakes and clamp it to the outer carbs so it is tight over the inner ones. This will allow you to actually ride it around the block, but it is not nearly accurate enough to use for jetting checks.

.

[mazza_gs1000]

Thanks for all of the responses. Now I will wrestle with the airbox to get it back on.

Now that I know that I can make adjustments to the carb with everything attached, what kinds of adjustments can be made?

And with the fuel petcock on the tank, I have to turn it from front to back with a pair of pliers because it is so difficult to turn. Does that have anything to do with it not continuing to run?

And with the PRI setting, fuel will flow freely. How long do I keep it on that? And when do I switch it over to Run? After the bike has run for a while?

Thanks for taking pity on a newbian, but I have never had a bike; and this is how one learns, right?

Thanks!

[Steve]

... and this is how one learns, right?

You betcha.

With your carbs, there are only two adjustments.
One is the large knob that is below the carbs, between #2 and #3. That is your idle speed adjuster.
The other adjustment is the small screw with a locknut on the throttle shaft between each pair of carbs. This is the sync adjustment screw.

The function of the idle speed adjuster should be obvious.

If you have had your carbs off and apart for cleaning, you should check the sync when you put them back together. We usually adjust them visually to get them close (this is called a "bench sync"), then use a set of gauges and do a "vacuum" or "dynamic" sync when the bike is running. There is information on how to do these procedures in your service manual, with further enhancement by the pictorials on BassCliff's site.

.

[Suzuki_Don]

If you have to turn the petcock lever with a pair of pliers then there is something definitely wrong. And there could be other issues inside the petcock. I would not trust a petcock in that condition. If the lever mechanism is gunked up then probably the rest of it is as well.

You don't really use PRIme under normal circumstances. It gets used when the float bowls are empty and you need to fill them up before you hit the starter button. After a carb rebuild or if the bike has sat for a long time and not been started, e.g. after it has sat through winter.

The ON and REServe positions of the tap will only operate when the motor is running as they require engine vacuum to open their diaphragms to allow fuel to flow. This does not apply to the PRIme position.

[Suzuki_Don]

With your carbs, there are only two adjustments.
One is the large knob that is below the carbs, between #2 and #3. That is your idle speed adjuster.
The other adjustment is the small screw with a locknut on the throttle shaft between each pair of carbs.

STEVE what about the mixture screw.

[mazza_gs1000]

Thanks for all of the responses....

I put the air cleaner back on, making sure I connected the big center vacuum line.

From how I bought it, I don't think it has been run in a long time.

Thanks Don, for telling me that the petcock might be bad. I did notice, however, that when the tank is off and I turn it to PRIme, fuel gushes out. Now that's not to say that it works in the Run position, but thought I'd note that.

So, I replaced the plugs and have all of the vacuum and fuel lines attached properly. So would that lead one to believe the problem is in the fuel delivery? If the petcock is bad, then it wouldn't run, right?

I also read on another post to check the gas cap for leaks due to the vacuum/gravity thing, and it appears to be okay...

[Suzuki_Don]

To check if the ON & REServe are operating properly. Remove the tank, put petcock lever in the ON position with plenty of fuel in the tank. Connect a hose to the vacuum nipple on the petcock and suck. This vacuum should allow fuel to run out of the petcock. If that works OK then do the same on REServe.

While the tank is off the bike on your work bench you can check the fuel flow with the petrol cap closed and then open to see if you can see any difference in fuel flow (into a container of course)..