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Main Area => General GS500 Discussion => Topic started by: Garrett on March 12, 2011, 06:10:59 PM

Title: Another Carb question
Post by: Garrett on March 12, 2011, 06:10:59 PM
Got around to attempting to start my GS today cause it was nice out.
Emptied the tank as best we could, put some fresh gas in it and tried firing it up.

I think my choke is broken
(http://i.ebayimg.com/00/$%28KGrHqYOKpME1qk46tk7BNcuH0NqSg%7E%7E_3.JPG)


pic is from a set of 1992 carbs on eBay (mine's an 89) but the black things that are in the "hole" do not move when I physically move the choke linkage, in this pic right where his thumb is, back and forth. Are they supposed to? I can push them up with my finger but otherwise they do not move  :dunno_black:

(http://i.ebayimg.com/00/$%28KGrHqEOKj8E0pUCmEF%29BNcuHBkswQ%7E%7E_3.JPG)


The bike will start if left sitting with the fuel on for a minute then die. It seems like the bowl is filling up but it's slow. Then when you go to start it, it sucks in that fuel in the bowl and can't refill soon enough so it dies. Sound plausible?

Thanks
Title: Re: Another Carb question
Post by: 4strings on March 12, 2011, 08:06:51 PM
Can you post a pic w/ the black things you're talkin about circled?  I'm not really sure what you mean.
Title: Re: Another Carb question
Post by: Garrett on March 13, 2011, 03:23:29 PM
(http://i21.photobucket.com/albums/b297/ihavesomeidea/carbs.jpg?t=1300054997)
Title: Re: Another Carb question
Post by: Unsane on March 13, 2011, 03:40:51 PM
They are the piston valves - they are not mechanically linked to the choke mechanism - rather the choke creates an air bypass past the butterfly valves and the increase in air flow through the carby will pull the piston valves up via vacuum

Can you keep the engine running with the throttle and does it wun OK when its warmed up?
Title: Re: Another Carb question
Post by: Big Rich on March 13, 2011, 05:25:53 PM
If your carbs are taking a long time to fill, it could be the vacuum lines between the carbs. Or a blockage in the fuel line or something.
Title: Re: Another Carb question
Post by: Garrett on March 13, 2011, 09:18:15 PM
I had to keep the thing pinned and even then I could only get it to run for like a minute or two a few times. I tried starting it a few more times but didn't wanna burn out the starter.
Title: Re: Another Carb question
Post by: burning1 on March 14, 2011, 10:44:47 AM
Quote from: Big Rich on March 13, 2011, 05:25:53 PM
If your carbs are taking a long time to fill, it could be the vacuum lines between the carbs. Or a blockage in the fuel line or something.

Bad petcock? Failed pet-chicken diaphragm?

The first thing I'd do is try running the bike on the reserve setting. If that fixes things, the problem is definitely not the carbs. Second thing I'd do is a rebuild. That old, the carbs would probably benefit anyway.
Title: Re: Another Carb question
Post by: Big Rich on March 14, 2011, 03:35:53 PM
Sorry Burning, but do you mean the prime setting? Just want to clarify......
Title: Re: Another Carb question
Post by: burning1 on March 14, 2011, 04:01:39 PM
Sorry, I meant reserve.
Title: Re: Another Carb question
Post by: JAY W on March 14, 2011, 04:03:28 PM
Try on prime this will gravity feed carbs rather than via vacuum,best for when carbs are empty.Do not leave standing on prime for long periods,if you have a float stuck open will dump fuel into airbox/cylinder.
Title: Re: Another Carb question
Post by: Garrett on March 16, 2011, 06:36:17 AM
Quote from: JAY W on March 14, 2011, 04:03:28 PM
Try on prime this will gravity feed carbs rather than via vacuum,best for when carbs are empty.Do not leave standing on prime for long periods,if you have a float stuck open will dump fuel into airbox/cylinder.

I'm not at the bike now but is prime on the Petcock or what
Title: Re: Another Carb question
Post by: jacob_ns on March 16, 2011, 06:44:08 AM
Yes, Prime is a selection option on the petcock for fuel control.
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