Carb woes after valve cleanup.

[scottsgs]

Hi all,

I did a valve lapping late last fall before I put the'81 GS850G up for the winter. I noticed that the bike starts up fine, and warms up fine, but once it is warmed up, the idle either stays up around 1500 or the rpms drop to the point the bike stalls. Before anyone says "intake 0-rings" or "intake boots" they were done 2 years ago when I bought the bike. I did notice that if I touch the choke rail on the left carb, it will have and adverse effect. I am trying to get the bike mechanically sound so I can sell it. I am thinking of getting one of the carb o-ring kits and doing another carb dip. Any help will be greatly appreciated.

Scott

[rapidray]

Scott, check all the orings on the choke plungers. That's where I would look first from your statement above. Ray.

[scottsgs]

Scott, check all the orings on the choke plungers. That's where I would look first from your statement above. Ray.

Well that is done. Still does the same thing. A local shop thinks the pilot jet is too small. I am at a loss as to was it could be. What is the number of turns out on the fuel/air screw? I thought it was 2.5 turns?

Scott

[hampshirehog]

I'd also check that all those plungers move freely (completely freely - there's not a lot of spring tension to overcome potential friction) plus check that the plunger seating hasn't gone brittle / cracked.

[Suzuki_Don]

I'd readjust the idle mixture screws via the highest idle method. The idle sounds too lean to me and giving you a roaming idle speed. 2 1/2 turns out is not a magic number that makes the motor idle properly. You have to get the mixture right by the highest idle method.

[Nessism]

A local shop thinks the pilot jet is too small.

Scott

Good example why you should NEVER take your bike to the shop.

[scottsgs]

Good example why you should NEVER take your bike to the shop.

I actually did not take it to the shop. The owner is a well known bike AtV and boat mechanic. He is really good about people asking his opinion. He doesn't try to railroad you in. Just a good all around guy.

[Don-lo]

What is the adverse effect after touching the choke? It dies faster? I would check to make sure no carb, especially #1, has loose rail attachments. The petcock vacuum line is also in that area, and maybe it has a crack that opens more with contact.

[Steve]

What is the number of turns out on the fuel/air screw? I thought it was 2.5 turns?

I'd readjust the idle mixture screws via the highest idle method. The idle sounds too lean to me and giving you a roaming idle speed. 2 1/2 turns out is not a magic number that makes the motor idle properly. You have to get the mixture right by the highest idle method.

While 2.5 turns might be where it ends up, I usually start at 3.0 turns, then adjust from there.
Even if it's too much, it will start well and idle reasonably well with the richer mixture.

.