what did we miss?

[Grif]

We just finished rebuilding the carbs on my 1982 GS850G. The pilot mixture screws are open almost 3 turns and it still won't start without the choke. As soon as the choke is released, the bike dies. What adjustment did we miss?

Thanks,
Grif

 

[frosty5011]

Could be a number of things, clogged passage(s), improper float height, etc. You'll have to explain what your process/definition of "carb rebuild" was. That'll help narrow it down.

 

[flyingace]

Are we talking about a bike that is already warmed up? No 850 will start without the choke when it's cold.

 

[DaveDanger]

Where's a wet noodle that I can smack flyingace with??? My 81 GS850GLX starts every time with little or no choke, hot, cold, or in between.... Admittedly, it may not idle very well without the choke, but it will crank every single time.\\/

 

[rckrzy1]

I HOPE you didn't break the tips off the very fragile idle needles ? Seen that before if you bottom the idle pilot too hard they break off sealing the idle passage.

 

[KEITH KRAUSE]

The mixture screws shouldn't be 3 turns out in an attempt to start the bike. If stock, they should be about 1 1/2 turns out. Then adjust for highest rpm once the bike will run well.
Most common mistakes during most CV carb rebuilds is one or more diaphragms installed wrong/not seated correctly. Also, a good bench synch may get it running. Followed by a vacuum tool synch.
Are you sure you didn't introduce an intake leak(s) at the manifolds during the work?

 

[Grif]

Thanks for all your help. Carb rebuilt = disassembled the carbs, soaked them in chem-dip, replaced seals and jets from a carb kit, then put it back together again.

The jet needles are all good and the floats are adjusted properly as far as we can tell. We tried starting the bike with the stock 1.5 turns on the pilot mix screws and it wouldn't start... they were slowly adjusted up to 3 turns.

My best guess at the moment is that the carb kits I got might have contained substaintially smaller jets than were stock. That would keep enough fuel from getting into the mix until the choke was fully opened... I'll pull them out tomorrow and compare with the old ones to determine if this is the case.

Anyone else have any ideas?

 

[Guest]

Adjust your float on the step down of the hinge. Not at the top. I made this mistake on my first rebuild and had similar problems. The new float needle valve and seat will alter your float adjustment so don't blow off this step.

 

[KEITH KRAUSE]

See my first reply. Except for the mixture screw adjustments, you didn't mention if the other things are known to be done correctly.

 

[bwringer]

I've run across several aftermarket carb kits with incorrect jet sizes. Your best bet is always to clean the stock jets and put them back if possible.

Also, the kits do not contain some of the o-rings you need, and the o-rings that they do contain are often the wrong sizes:
http://cycleorings.com/

 

[bwringer]

Also, make sure the side covers on the air box are properly sealed and mount the airbox before you try to start the bike. A GS850 normally won't start or run without the airbox, and will never run well if it's sucking in air via deteriorated foam seals in the side covers.