GS850 backfires and lacks power

[dbarnes42]

I have a 79GS850, completely stock. My origninal problem was the #3 exhaust wasn't getting hot. After dipping and cleaning the carbs, I installed new intake boots and o rings, replaced all of the o rings in the carbs, new boots from air box to carbs, coil relay mod, etc. I took the bike around the block today and at first, it was sluggish but seemed to run better after a couple of minutes. So, I went home and shut the bike off. After about 15 minutes, I took her for a trip. Power was way down and there was a noticeable backfire through the pipes. Power was sluggish and the bike would lurch forward at times. Max rpm I could get was about 6K. But the good news is the #3 exhaust is getting hot now! The pilot fuel screws are at 3/4 turn out and the pilot air screws are at 1 turn out. It doesn't want to start unless I use the choke.

[Big T]

It's still lean - take the air screws out to between 1 1/2 - 2 turns

Did you use the fast idle method?

Have you synced the carbs?

If it doesn't start without the choke, most likely your pilot jets are still clogged.

What happens when you leave the choke part way on and ride it?

[dbarnes42]

I will try and adjust the air screws out. I worked on it yesterday and it was backfiring through the pipes at idle. It sounded like a gun going off everytime! What is the fast idle method? The carbs were bench synched and vacum synched. It will start with the choke, but still backfires. I also haven't tried to leave the choke part way put and tried to ride it, but I will.

[Gimpdiggity]

You're running really lean right now.

Richen it up especially on that idle circuit.

[82Shafty]

Just checking... you did install the air box with the air filter correct?

All air box seals are in good shape?

[bwringer]

And the valve clearances have been checked and adjusted, right? RIGHT????

[dbarnes42]

This is where I am at now. The airbox has been installed with the air filter in it and the seals are good. I worked on it some more last night and it got to the point where it wouldn't back fire anymore, but it had no power at all! I tried to ride it around the block and everytime I put it in gear it would die. It was also very hard to start. It didn't to start with or without the choke. The only way to get it to start was to give it a little throttle. I also noticed that now the #3 and #4 exhaust are not getting hot. I am really lost!