GS 850G Carb problem

[Anonymous]

I have a 1980 gs850g. It idles ok, a little cold natured. But it just does not seem to accelerate smoothly. Right off the bat it seems fine untill about 3000 but it seems slugish and than after that it seems to really hesitate. I know it is getting feul from the tank so I can eliminate that. It also gets good spark from all plugs, as well as good compression. However after riding a while it seems to blow smoke out of the right side of the exhaust, like one of the plugs is fowling and starts running ritch, but the plug does not fowl. once worm the bike seems to have trouble idiling. I was looking at a diagram and noticed that the one set of jets in the carbs have a plug but mine have not plug on them. Any ideas would be very much apreciated.

[flyingace]

This sounds strangely familiar to a problem some of us have had with our 850s. Three of us had a over-rich condition in #4 cylinder.

Have you looked at the #4 plug when it is idling badly? If it is black and sooty while the other plugs are clean - I might be able to help you.

Ace.

[Anonymous]

thats sounds like the problem. i keep pulling the plugs to kleen them but 1 2 and 3 are fine but number four is black

[flyingace]

Well join the club!

The reason underlying this problem is that when the bike is on the sidestand, rainwater can run into the cavity containing the pilot mixture screw for #4 carb. The water just sits there, seeping into the PMS. This water corrodes the components and crud (rust?) blocks the orifice in the carb throat.

You will need to remove #4 carb and clean out the PMS and orifice with carb cleaner and compressed air, then replace any component that is corroded. The spring was at fault in my case.

Hope this solves your problem.

Ace.

[Anonymous]

thanks for the help. i will give it a try and see what happens.

Derek

[Anonymous]

one quick question. should my slow jets have the rubber plugs. If they are, the guy who had it before me must have removed them.

[flyingace]

I'm not familiar with 'slow jet'. If you mean the pilot jet inside the float bowl, yes they have rubber plugs over them and should remain that way. If you mean the pilot mixture screws, they are uncovered.

Ace.

[Anonymous]

gs1000

Since we're on the subject of carb problems. I have a 78 gs1000. It back fires on decel and cuts out when accelerating. All the cylinders have fire, and the plugs are clean. I checked the pipes and they're all hot. The compression is good, but it still cuts out on accel. And it also bogs down and falls flat around 5000rpm. You can smell fuel at idle. It passed emissions with 7.45 CO and 1545 HC. Max readings are 8.00 CO and 1800 HC here in Phoenix, Az. Any suggestions or ideas?

[flyingace]

If the plugs are clean, this sounds like a lean condition. Possibly an intake leak? Beyond that, my area of expertise is pretty narrow and the expert users can offer more help than me.

Ace.

[KEITH KRAUSE]

Re: gs1000

Since we're on the subject of carb problems. I have a 78 gs1000. It back fires on decel and cuts out when accelerating. All the cylinders have fire, and the plugs are clean. I checked the pipes and they're all hot. The compression is good, but it still cuts out on accel. And it also bogs down and falls flat around 5000rpm. You can smell fuel at idle. It passed emissions with 7.45 CO and 1545 HC. Max readings are 8.00 CO and 1800 HC here in Phoenix, Az. Any suggestions or ideas?

Some basics first.
If you still run points/condensors, I'd at least clean the points, make sure there's no pitting, make sure they contact squarely, then I'd set the dwell and ignition timing. Lube the mechanical advance and check advance action. If any doubt or points are pitting, get new ones and condensors.
Might be a good idea to check/clean the plug caps and check/clean/the lead ends. Check plug gaps too. Clean battery posts and top off with distilled water. Clean/tighten coil terminals.
Check air filter.
Set the side air screws using the highest rpm method. Test.
If it still has the problem, a carb cleaning/rebuild and synch may help.
Is the bike stock? If not, what mod's? The jetting may be way off.
Any other problems? Does it leak fuel anywhere? Dark exhaust? Does the bike idle much higher when hot as compared to cold/warming up?