GS1000G questions

[chef1366]

That's what I would do. Is the hole you are referring to next to your slide port in the top diaphragm section of the carb?

[Backtobiking]

No. The tiny hole I was referring to is pointed by the red arrow. It is all the way down at the bottom of the slide tunnel and about 1/2" or less from the larger hole where the needle jet used to seat in. None of my stock carbs has such a hole. According to the seller, these carbs were pulled from an 82 or 83 GS1100GL or GK.


I I am still curious if this hole may affect my carburation with my stock main and pilot jets transferred over.

My family obligation took me away from my garage. I hope to get up early tommorrow and start work.

Thanks very much for quick reply.

[Dink]

That is a "progression hole" is a good thing, much sure it is clear.

Dink

[chef1366]

He already bought a replacement carb. I'd say just add it to his existing rack.

[Backtobiking]

Following Chef’s suggestions, I reused the main and pilot jets from the original carburetors and replaced all O-rings and most other components with the O-ring and K&L kits. I tried from 1 to 3 ½ turns on the air screws in ½ turn increments. The bike consistently started right up even in the cold but idled roughly with backfiring intervals averaging every 40 seconds or so.

The person who worked on the carburetors before me was a butcher on steroid. He stripped 2 of the air mixture screw heads, 3 of the pilot air jets and couple of threaded aluminum holes which the tie rack bolts into.

As I was replacing the air filter, I noticed the air box had duct tape covering the right side opening and the left opening had a bad rubber seal that, had it been in good shape, would’ve provided a good seal with the metal cover. The air inlet of this black plastic housing facing the rear of the bike was also duct-taped some what. As a test, after I replaced the air filter, I taped the left side of this plastic housing but removed the duct tape covering the air inlet. All the few small round holes at the bottom of this air box remained unobstructed. Still, the bike idled roughly and misfired intermittently. Also, the engine’s RPM went up to around 2100 when warmed up.

With a fresh change of filter and 10W40 oil and the bike warmed up I raised the throttle to 4000RPM briefly and found the engine steadier and surer. Little misfiring still happened when the RPM decreased.

I cleaned the carbs with Gumout and cleared all passages. What should I do next? I do like to obtain a better air box but it’s not going to be easy. The rubber seals are going to be difficult to find. Could a poorly sealed air box cause my problems? Should I get a manometer and sync the carbs at this stage? Any suggestion?

Thanks in advance.


:shock:

[chef1366]

How are your intake boots and did you replace the o-ring behind them? There are still airbox boots available for your bike. Check here http://www.mrcycles.com/fiche_section_detail.asp
I would also get a synchronizing tool. Mercury sticks work for me. Some folks like vacuum guages or the Morgan Carbtune.

For sealing the airbox filter door I bought a roll of pickup truck camper sealer from Home Depot.

And to answer your question "yes" a leaky airbox will cause your bike to pop and run lean.

[Backtobiking]

I don’t recall having seen any O-ring behind any one of the rubber boots between the carburetors and the air housing. The air box side of each boot, as I remember, has a groove that snaps into the hole of the air box. In any event, I will replace all 4 boots as you suggested because one of them is slightly deformed, always wanting to pop out from the air box before it’s bolted back to the chassis.

Should I just remove the deformed rubber seal on the left side of the air box first and then tape this air filter access opening with what I think you referred to as the stronger and wider camper roof repair tape you mentioned?

I also noticed a gap above the top of the air filter element holder even after I tightened its screw. How do you rectify that?

Thanks.

:shock:

[chef1366]

There is an o-ring between the boot and where it bolts onto your engine.
What I'm referring to is the foam type one sided tape that goes around the lip of the truck bed to seal the camper shell. I used this as a gasket for the airbox lid. It should be able to seal any part of the airbox. (except for the boots of course)

[Backtobiking]

Very likely I will remove air box and carburetors tonight to take a further look. I do not recall having seen any O-ring in any of the boots between the carburetor output and the engine. But I may be wrong. Better yet, I may just seal the air box first and try out the bike. What about the gap on top of the filter element holder? Is your foam tape applicable here?

Thanks.

[chef1366]

Part number 29 is the o-ring.
This is very important to replace.

[Backtobiking]

I’ve been occupied with work and my 1 ¾ year old daughter in the last couple weeks and did not start the bike until this morning. I was going to seal the air box as Chef suggested. I was also going to pull the carburetors and clean them again. The bike started right up. With the air screws now at 2 turns out and idle screw adjusted, the bike was able to idle at 1K RPM without cutting off. I then rode to the gas station and filled up the tank with 89 octane gas. The bike does not backfire now. But I smelled a little bit of fume. Is it a sign of the bike running rich? If so, should I lessen the air by turning the air screws in, say, by ¼ or ½ turns or more?

The bike is a lot better than before. Idling acceptably, it does not backfire anymore. I don’t think the air screw adjustment has anything to do with the current state. It backfired before, I think, because there was either air in the fuel system (somewhere in the carbs) or there was a piece of dirt or gum blocking one or more of the jets. I will remove and read the plugs.

What was the factory setting for the air mixture screws on my 81 GS1000G? Everything in my carburetion is stock except the idle jets and air screws from the K&L kit because the old ones were stripped. There is no reason why I cannot set them back to factory default instead of by trial and error.

I am going to finish the carburetion first before I adjust the valves. I am almost there.

Thanks, Chef and everyone.