'79 GS550 Carbs

[Big Dog]

I am tearing down and cleaning the carbs on my 1979 GS550. I believe from everything that I am reading is that I have VM carbs on this bike???

They do not have the round cap on top they have the oval cap.

Will the carburetor clean & repair pictorial at the homepage of this site still be basically the same for me?

Can someone point me into the direction for settings for these carbs?

Jason

[KEITH KRAUSE]

There's a new VM carb service section. You should find it in the letters to the editors section now. About 8 topics down. Not sure if Frank added it to the garage yet.

[Big Dog]

That is perfect thanks a lot.

Jason

[KEITH KRAUSE]

You're welcome. Be sure to ask us if you have a question.

[Big Dog]

When you sink the carbs why do they say that you sink everything to #3? It looks as though you can adjust #3 just as easy as any other carb. So if you have broke all the carbs down to clean them where do you start? I am going to use the Motion Pro sticks to get them synced back up, is there a starting point that #3 should read on the merc stick?

Jason

[KEITH KRAUSE]

On some models, the manual says to synch the other slides to match #3.
My '79 1000 doesn't require that. If your manual doesn't say to, then start with any carb you like.
There's no "starting point" on any carb when it comes to vacuum level, if you mean a specific level.
I've always found that if you bench synch correctly and the bike is in good tune, including ignition timing, compression, valve clearances and the slides move smoothly, then the initial reads you see at start up will be OK. What you want to do is make them all even, at least so the difference from the highest level to the lowest level is within a 1/2" to 1". I always adjust the highest level(s) I initially see down to match the lower levels. Just my preference. It helps avoid what I call "idling off the idle adjuster". Sometimes you can play with the throttle valve adjusters (increasing vacuum) to the point that the bike is idling too high and this makes you keep lowering the idle with the idle adjuster knob. Before you know it, the idle adjuster isn't even contacting the pulley and you have no more control over the correct idle. That's why I suggest lowering the higher levels to match the lower ones. Use a couple of fans to cool the motor. Works for me.
For the most accurate synch, check timing, valve clearances and set the side air screws first using the highest rpm method.
Not sure what all you plan to do with your carbs, but I suggest the o-ring kit from Robert Barr, a member here. Also inspect your manifolds and the o-rings inside them. I always replace the o-rings. Check float levels too. Don't mix up the carb parts. Keep each carb with its components.