Carb trouble on skorpion.

[Srinath]

OK so I fixed the left carb emulsion tube that I had broken off. Then re fitted everything after cleaning everything. The needle clips are on #2 from pointy end on both. The air box and everything else is all stock. The air screw is @ 3 turns out.
This is what the bike does.

The bike starts great with choke when cold and on side stand. Then if I sit on it and turn the handle bar or pick up the bike the revs drop and it stalls.
The thing also seems to barely hold idle and surges like crazy @ low revs. Once you get it past 2K rpm in the lower gears it revs up fine.

I've read somewhere 7 1/2 turns on air screw, so I will try that next, but it seems excessive, I mean most bikes 3 is a good midway starting point.
I also suspect the cables are binding, I'll fix that. But anyone else have any other suggestions ? This bike ran fine with the exception of a choke that didn't work. Now that has been fixed perfect to the extent it works better than anythign else in the carb.

Thanks.
Srinath.

[billr]

The bike starts great with choke when cold and on side stand. Then if I sit on it and turn the handle bar or pick up the bike the revs drop and it stalls.
The thing also seems to barely hold idle and surges like crazy @ low revs. Once you get it past 2K rpm in the lower gears it revs up fine.

I've read somewhere 7 1/2 turns on air screw, so I will try that next, but it seems excessive, I mean most bikes 3 is a good midway starting point.
I also suspect the cables are binding, I'll fix that. But anyone else have any other suggestions ? This bike ran fine with the exception of a choke that didn't work. Now that has been fixed perfect to the extent it works better than anythign else in the carb.
Thanks.
Srinath.

When I had to clean my carbs on my then recently acquired Traveller, I counted the turns on the air screw. It was out 5.5.
When I reassembled, I tried air screw at 3 turns (hey, it's what the book said...)
...did not like it. Almost exactly the same symptoms you describe. I turned it back out to 6 and that is where it will stay.
Also, check for any air leaks or loose air filter...yes, I didn't tighten the screw on the air filter, thought I had tightened everything up...
it popped off and I could not figure what the heck was wrong...

[edfmaniac]

I'm at 7 turns out and happy. Sounds like your choke cable may be getting pulled when you turn the bars. Also make sure that your idle speed screw is touching the stop when you are at base idle. The previous owner of my bike was using the slack adjustment on the throttle cable to control idle and that just doesn't work. Another thing that I've discovered working on motorcycle carbs is that if something isn't right, it's usually easy to find as long as you are willing to take the carbs off as many times as needed to find the problem. It can be frustrating but I love the feeling you get when you finally get it right. Good luck.

P.S. The smallest piece of dirt or crud that you would find in a fuel system can foul up the low speed jet. Always double check that and keep a filter on the fuel line once you are certain that you have cleared all debris. I had to rebuild the carb on my XT225 a dozen times before I got all of the carb settings just right and found all of the rust and grime in the gas lines, carb bowl and tank.

[Srinath]

No dirt, assembled it yesterday after cleaning, and new full tank of fuel, all the old gas was dumped out and tank was dry. Its clean.
Now I turned it to 7 turns on air screw, no change.

So, I am now working on 2 theories.

1. Choke is not closing. It runs great after 3K really, if I feather the clutch to 3K and keep it there I will not even notice that surging. It even starts great so choke is opening but not closing I think.

2. I put the left carb slide on backwards. The cut away section facing the air box is how I fit it back, but I could have put it in wrong.

It did not do this when I opened it up for a non working choke, these 2 are major changes ... choke I think will now be non cable, all mechanical with a push/pull plunger. That would let me push the choke closed which a cable cannot do obviously. Of course I have to check the slide assembly, sadly I wont get time till later this week.

Cool.
Srinath.

[basser23]

Be aware that the choke is not really a choke..it is an erichment device...and spring loaded...if stuck it would run rich...

[Srinath]

I suspect as much, it seemed awful tight when I had the carb outside. But like a fool assumed it will close.
Cool.
Srinath.

[Srinath]

OK choke works, bike starts and does not surge and buck till 3K, great.
Now it wont idle, keeps stalling. In fact idle screw seems to have no effect ... any one think it needs more air screw ... less ? I am thinking of going to like 4 and working back 1/2 turn @ a time.

Thanks.
Srinath.

[basser23]

idle speed screw,not pilot air screw....idle should be 1250-1350 rpm,speed screw is on left carb at cable end..

[Srinath]

The air screw is @ 7 turns out. The idle screw, idle rpm and air screw are related, if your air screw is set too far out, as in its too rich it will not idle. If it is set too lean - too few turns out it will idle @ 1200 when cold and @ 3-4K when hot. I was saying I am going to set the air screw to 4 and work out or in from there.

The idle screw in my bike went from not even touching the throttle bell crank to being screwed in all the way and the thing still stalls when you let off the throttle. To me that is a good indication the air screw is set too rich. Unless somethign more serious is wrong - which I doubt.

Cool.
Srinath.

[edfmaniac]

Pardon me if I missed it, but did you loosen the throttle cable tension adjustment up near the grip to make sure that your idle speed screw is taking the whole load of the return springs on the carb? That's the only way to get a consistent return to idle position.

If the speed adjustment is screwed all of the way in, you are way too far open to be in the effective range of the idle mixture screw. Try slacking the throttle cables completely and turning the speed screw back down to where you can barely tell that it's starting to open the primary carb and try to start.

Make sure that the carbs are fully inserted into the intake manifolds and that the manifolds aren't cracked. You'll feel them snap in as the ridge and groove come together.(I was reminded of this when mine fell out a day or two ago)

Checked your float levels?

[Srinath]

Cable is adjusted fine but worth a second check.

The "carb fall out", yea its a feature on a 89-00 GS500 cos suzuki updated the 89-00 part with the 01+ part, which fits and works fine ... sorta. If you got a K&N riding on the back of your carb, the manifold will let the carbs slip out. Booya, instant DOA bike.

I will double check things, but see a rich mix @ idle will let the idle drop below the set rpm and rise back up slowly. Say you're @ 1300 and everything is perfect. Then you open the air screw 1/2 turn. That would make the bike drop to 1000 then slowly rise back to 1300 when throttle is blipped. Make it 1 turn and you're now going to drop to say 500 ... @ which point it will just stall. That is my main backbone theory.

Cool.
Srinath.

[Srinath]

I got it idling just fine, 3-4 turns on air screw, but it is pretty low, like under 1000 rpm, I am thinking of turning the airscrew another 1/2 turn in or somehtign like that.
Cool.
Srinath.