82 gs650 driving me nuts. Smoke/backfires, only runs on choke

[Sevtovit]

Hey all. So I have been looking through old posts for a week and can't find anything to help my situation. Im going nuts and about to give up on this pos. Sooo, I have an 82 gs650 G I completely rebuilt and had running and turn key last fall, I would say, 95% correctly. Last fall a patch I had made in the tank failed and so I stored it over winter. This summer I got a brand new tank, this one with a gravity fed pet cock (the vacuum line on the carb is plugged), I completely cleaned out and inspected the carbs which were previously rebuilt using a dyno jet kit (the pipes are open so the main jets are two sizes larger than stock). Since the incident with the tank i replaced the rubber plugs under the pilot jets and the needle valves, plus i rechecked the float hight for good measure. It has new air pods, new plugs, new oil, new oil filter, clean gas, and a new battery.

All four cylinders have compression and are about 90psi each. I can get the bike to start but only with the choke on and there is a bunch of white/blue smoke, back firing, and misfires. What I can't understand is what happened from last year tp now because nothing seems to have changed. This is the bikes last chance. If not i think I'll send it off a cliff. Please any help would be greatly appreciated.

[Nessism]

Bad karma from the open pipes...

[Big T]

What about your valve clearances?
The symptoms you describe point to tight valves/dirty carbs/ too lean from the pods

And, yeah, open pipes cause running issues

[Redman]

Seems that the answer to “what happen in the year it sat” was that it sat for a year. And in that time more stuff can clog up the passages in the carbs.

tell us more about what you did to clean carbs. If it was you looked and it looked good, that is not enough.If it was spraying some carb cleaner, that is not enough.

[Steve]

I agree that the open pipes are not helping anything, but can only suggest that two sizes up on the mains is not enough.

On the other hand, that only means that the pipes will be quiet soon enough. opes:


Can you tell there is not much love for open pipes? Partly because it causes a bunch of headaches trying to tune the carbs, but mostly because of all the headaches you are causing your neighbors. Motorcyclists are already given the "evil eye" by the general population, why give them another reason to believe what they already think?

Valve mis-adjustment can cause some of your symptoms, but the symptoms show up gradually, not all of a sudden.

One last thought (question): how did you "completely cleaned out and inspected"? There are SO many details that can be overlooked and SO many shortcuts taken, it's very easy to do them wrong. Let us know exactly how you "cleaned" them.

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[Sevtovit]

Yes the thing that puzzles me is that i had it running almost perfectly with the current set up and I can't find any big change. I did make sure all of the valve shim clearances were to spec when I did the rebuild. When I stripped the carbs this summer i pulled all of the jets and soaked them and then went through and sprayed cleaner followed by compressed air through every port and channel i could find. Also I forgot to mention I replaced the intake boots as well.

[Steve]

How long has it been since the bike was run ON THE ROAD?

Firing it up in the garage doesn't count, when was the last time it ran "normally", on the road?

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[Sevtovit]

I took it out the week before the tank incident so at this point about a year.

[Steve]

Time to clean the carbs PROPERLY.

Spritzing some spray is not the way to do it.

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[Sevtovit]

Yeah i was afraid of that. Is there any particular chemical dip you would recommend? Also, do you use an ultrasonic machine? Thank you.

[Steve]

One of the forum favorites is Berryman's Carb Cleaner Dip in the one-gallon can. (NOTE: there is only about 3 quarts of liquid inside.) Another common one is GUNK brand Carb Cleaner Dip.

There are a few here that use an ultrasonic machine (I don't have one yet), but the solutions vary wildly, I have no idea what to recommend.

When you get your 'dip', read the directions on the can, then ignore them. They say to dip the parts for 15-30 minutes, but those directions where written back when the chemicals inside could actually do the job in that amount of time. Since all the safety weenies took over and changed the chemicals, you need to dip the parts for 15-30 HOURS to clean them properly. Then rinse with the hottest water you have, and follow up with the spray of carb cleaner and compressed air.

If you haven't already done so, install a new set of o-rings from cycleorings.com.

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[Sevtovit]

Understood. I was thinking a 48 hour bath would be appropriate. I definitely appreciate the o ring source! I will report back with result, hopefully by end of the week. Thanks

[Steve]

Don't do a 48-hour bath, stick to a 24-hour maximum.

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[Sevtovit]

Will do. Thanks for the heads up.

[Sevtovit]

Allrighty Mr Steve, time for an update. Pulled apart and chem dip all the carbs and jets and metal pieces. Cleaned them super well, lot of hot water. Put them back together, using the GS carb guide on this site. Now I have the opposite problem, when I start the bike it goes all out full throttle, even with the throttle cable detached. Choke does nothing in any position. I tried adjusting the air screws to both 1/2 turn and 4 turns, same result (they were set at 2.5 turns). Again to clarify, new orings in the carbs from cycle oring. New boots with their orings, new plugs, new air pods. Back to hitting my head on the wall.