Hi all! First post! (if you don't want to read it all, read just the last paragraph...  )
I've just bought a 1997 GS, that German limited edition with fairings. Just 18.000 Kms (11.000 Miles), but has been in the garage for long time and with gas in it.

Long story short, the carbs had been cleaned by a lousy mechanic that assembled the bowls in the wrong way (right in the left, and left in the right) and bike run badly. 
Took the bike to a good mechanic, he corrected, synced and tuned the carbs. Bike has been running good, but it still has problems:

• Poor Mileage - started with 30mpg (US), after air filter change rise to 40mpg(US), and a very, very conservative driving (I used to get 85mpg in a 70mpg bike) 
• Left plug with dry, black carbon deposit, and the right one clean, almost pink coloured (?!!)
• Took the tank of in order to sync it myself when I found out that it doesn't have a cap on the right carb vacuum port!!(I suspect the first mechanic lost it). The left one has the hose that goes to the petcock
• EDIT: The bike idle after warm up somedays is at 1250RPM, other days goes to 1500RPM. Is this normal? In cold, bike starts without choke at 1000RPM.

Now, in a 1997 GS, the vacuum port in the right carb is supposed to have a cap in it, right? Should I place one, or should I go to the 2nd mechanic to retune it properly before installing the cap?
Or after all, it doesn't need the cap like a 95 GS as in this thread: http://gstwins.com/gsboard/index.php?topic=34003.0 ??

That port should be plugged, so it shouldn't need one.  I stuck one on mine 'just in case,' but it didn't seem to affect anything.

Thanks for your reply.
Can you please explain what you mean by "that port should be plugged"?
Sorry for my lack of English abilities...

One update, I placed a tube in that port, and the other end in colored water to see if there was any suction, and there wasn't!
Maybe I'm checking the wrong port...its strange because in the left carb, the vacuum port that connects to the tube going to the petcock is in the same exact location...

Where should I connect the hoses if I was syncing the carbs?

are these the ones u are talking about?


my stock 94 petcock had a hose going from the right one to the petcock.

mine went bad and changed it to a different one here http://gstwins.com/gsboard/index.php?topic=56352.0
therefore I had to cap those off.

if u have a stock petcock I do believe (like mine did) the right port should have a hose going to the rear port of the petcock.

Quote from: Tombstones81 on August 15, 2011, 05:25:29 PM
are these the ones u are talking about?


my stock 94 petcock had a hose going from the right one to the petcock.

mine went bad and changed it to a different one here http://gstwins.com/gsboard/index.php?topic=56352.0
therefore I had to cap those off.

if u have a stock petcock I do believe (like mine did) the right port should have a hose going to the rear port of the petcock.

Exactly! Those two ports!  I've seen that picture during my research, and I'm based in that pic.
And yes, there is a tube going from one of those ports to the petcock, although it isn't the right carb, it's the left one (the one closest to the petcock).
The other port, the "right" doesn't have anything connected to it, it's open to the air.  I've just connected a tube to it and the other end in colored water. After I start the bike and rev it, there wasn't any suction at all! Should't there be suction? That's the principle of the carb sync yardstick method, right?   

Thanks.

I would cap it off just incase.

see if anything helps then.

The right carb is plugged internally with a little brass plug.  No need to worry about it.  Only three places to tap vacuum on those carbs....the left carb, and the two on the top. 

Quote from: scottychop on August 15, 2011, 09:09:38 PM
The right carb is plugged internally with a little brass plug.  No need to worry about it.  Only three places to tap vacuum on those carbs....the left carb, and the two on the top.

Explained! Thanks!

That's might be the reason that it didn't make a noticable difference tapping it or not.

So, if I were to sync the carbs, I should use the caps on top, right?

And about the fuel consumtion, what should I look to in order to get a lower consumption?

Regards,

Quote from: piresito on August 16, 2011, 02:12:52 AM

Quote from: scottychop on August 15, 2011, 09:09:38 PM
The right carb is plugged internally with a little brass plug.  No need to worry about it.  Only three places to tap vacuum on those carbs....the left carb, and the two on the top.

Explained! Thanks!

That's might be the reason that it didn't make a noticable difference tapping it or not.

So, if I were to sync the carbs, I should use the caps on top, right?

And about the fuel consumtion, what should I look to in order to get a lower consumption?

Regards,

The two black caps on top are the ports for balancing/syncing the carbs.


Just a heads up on the brass cap in the vacuum port.My 89 did not have brass cap in the vacuum port like most other carbs.I used vacuum caps to block them.Even if you do have a brass plug in there,it never hurts to have a spare for road side repairs.

Nice! Thanks people!
Now I have to check why the high consumption...

Check your sprockets.I believe that 16 tooth engine and 39 tooth wheel sprockets are the stock sizes.I get in the mid to high 40mpgs with my bike and it's heavily modified.

Thank for your reply...
Both sprockets are stock! Except for the new air filter, that reduced fuel consumption when I bought it (HFA 3503), all the bike is stock, carbs were cleaned very recently... 
BTW, I think the carbs have two turns each, in their screws. Is it a normal setting? I've been reading that I usually is around 3 turns, right?

Quote from: piresito on August 18, 2011, 02:33:01 AM
Thank for your reply...
Both sprockets are stock! Except for the new air filter, that reduced fuel consumption when I bought it (HFA 3503), all the bike is stock, carbs were cleaned very recently... 
BTW, I think the carbs have two turns each, in their screws. Is it a normal setting? I've been reading that I usually is around 3 turns, right?

If it is running and idling correctly,I'd leave it.Opening the screws allows more fuel to flow though the idle/pilot circuit in the carb.Backing them out 3-3.5 turns can help cure hanging idle when the engine is warm.

Yep, its running perfectly! Idle at cold 1000 RPM, idle warm at 1500 RPM.
Although the consumption is high for such a moderate driving.
I guess I will just take it to the mechanic for a full carb adjustment...the only problem is that he thinks this consumption is normal! :-S

Thanks!