vacuum leek ?

[moon]

I have a 79 gs 750 im hearing a hiss and it realy isnt running right I took it to my buddy and he told me it sounds like a vacuum leek and there should be a hose running from the petcock to somewhere on the motor so it suck gas in now he is a Harley tech so dusnt know for shure any ideas on the problem

[MisterCinders]

Your vacuum line runs from petcock to the No. 3 carb. It's the smaller line off the petcock. If that lorry is open on the carb, your bike will have a hearty air leak.

[moon]

Ok not to sound like a dumb ass but witch carb is the number 3

[koolaid_kid]

Left to right as you sit on the bike: 1 - 2 - 3 - 4

I enjoy reading your phonetically correct posts, so it is not a dumb question.

[moon]

ok cool I was looking at the right one now where dus the vacuum line hook up its not the brass port that points down us thats an overflow for the bowl right

[Steve]

Looking at the back of the carbs (the airbox side), look for a port near the top of the inlet, but toward the left side of the carb.
Actually, three of your carbs will have a port that looks like this, but this one acts different.

The similar port on #2 is the vent line for #1 and #2, the port on #4 is the vent line for #3 and #4.
The port on #3, though, is the vacuum port that is supposed to be connected to the smaller port on the petcock.

If you need a picture, I can dig one up.

.

[sedelen]

I had found a vacuum port sync tube still in my vacuum port on my No. 2
cylinder after I got my '79 GS1000E. Who knows how long it had been there. I know I had put about 1,200 miles on the bike before I found it. Can't believe it ran as good as it did. Actually it didn't make much difference when I replaced it with a allen screw and crush washer.

[allojohn]

Here you go moon.

[moon]

You guys are awesome

Off topic a little but what are your guys experinces with manuels cus im haveing a tarable time with mine it is verry vague and for example I looked up petcock in the index and it told me page 200 it was actualy on 220

[cowboyup3371]

What manual do you have?

[allojohn]

I use the Haynes, Clymer and the downloaded pdf workshop manuals from the BassCliff site. All are useful and help me understand "how to" a bit better.

[moon]

Sorry I thought I said clymer but I gues I didnt

[cowboyup3371]

I think it just depends on the manual. I know if you look at the service manuals on Basscliff's site, you'll find the paging is off. That's a feature of Adobe and can be adjusted but has to be done at the time the PDF is created.

You'll do fine to have multiple manuals (I use Clymer and the Service Manual) but remember there's a lot of information on here to use that may not be in the manual or may explain it better.