fuel and bing carb question on a GS6

[quiggs00]

ok first is a fuel question what is the deal with leaded gas should i be running that i just got a manual and it says to use leaded? second, i am running the original bing 45 or 54 i cant remember the number but its on the 400cc. Anyways, i was wondering if anyone else running this carb new how there carb is set up.  I mean how many turns out from closed is the air screw and idle speed screw also the same with the jet.  The bike is running really rich so rich it sputters oil out the exhaust and will run for just a little bit.  could this have to do with running unleaded opposed to leaded gas?

thanks in advance!

[hrbay]

Hello quiggs00, it sounds like your float is hanging up.

GC

[Steve Minor]

Modern pump gas is fine. Just keep it fresh. The oil I use is Castor 927 mixed 40:1, but everyone has their own favorite.

This is the stock jetting I got from Bing for my 1977 400 GS6.
I run my air/fuel screw 1&1/4 turns out from bottom.

44-051-185 Main Jet
45-120-3,22 Needle Jet
46-360-401 Jet Needle in position 2 from top
44-353-50 Idle Jet

[tomale]

quiggs,
I think Hr is on to something. At the very least you need to see what is up with the float bowl. There maybe something holding the float valve open. how long has it been since the bike has run before? If it has been a long time the Carb may need a through cleaning.
Second this problem is not related to unleaded gas. It would do this wheather you were running leaded or unleaded. It is possible to find leaded gas but it is sold as race gas. In my opinion unless you are competing as an expert then it is just not needed. It would help it run faster and some what better but doubt it would help in this situation. It is really expensive. better to start with the simple  and basic stuff
The position of the Air mixture screw is subject to change depending on what jets you are running and the situation the bike is being ridden. Temp and Altitude changes will effect how much the screw needs to be turned in or out. Basiclly if the jets are correct and the carb is fuctioning like it should. the airmixture screw should be turned out about two full turns. This is a plus or minus kind of thing. In cooler situations it may need to be turned in a 1/4 turn out to lean out the mixture because the air is denser and the gas does not atomize as quick. As it warms up you may need to turn in in a 1/4 This takes time to get a hang of. most people just leave it alone once they get it close. I know of several guys that turn their air mixture screw in a turn or so to start the bike and then as it warms up they turn it back out.
I would start with the carb itself, make sure it is clean and that the connections do not leak. If the bike has a reed valve that can cause some troubles too so make sure they are in good shape... no cracks or chips and they seat correctly.
hope this helps... knowledge and wisdom are your best resources, so keep the questions coming.The only question that is dumb... is the question we do not ask. I wish you success.

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
78' 400 MC5

[quiggs00]

thanks for the info! now also if i am doing these test and such with the air filter off or with a modified one would that cause it to run differently?