xs11 newbie questions(i.e. carb troubles)

[tranger03]

I recently bought a '78 XS1100 and now I am trying to get the thing to run. The bike is in pretty good condition overall but was sitting for a long time. Unfortunately, the bike was not running when I bought it (what do you expect for $400). My questions mainly have to do with the carb adjustments, I think. Let me list what I have done to the bike thus far.

1. changed the oil.
2. new plugs
3. new battery
4. cleaned carbs following the guide on this site
5. new carb boots (engine side)
6. tryed to pre synch carbs with bread wire gauge
7. rebuilt both petcocks

Now, after "pre-synching" the carbs I tried to run it and here are the results.

1. The bike will start on choke
2. It will idle for about 10-15 seconds
3. #3 and "4 cylinders don't appear to be firing
4. It is idling around 1000 rpm according to the bike tach
5. If I let off of the choke any time the bike will die.
6. If I try to give the bike any throttle it will die

I know that the bike will run I just need to get these carbs dialed in. I have merc sticks but I can't get it to idle long enough to use them. Any help would be greatly appreciated as it is a beuatiful southern california day and I would love to take it around the block a couple of times.

Thanks

[Pat Kelly]

Are you sure you have fuel flowing from the right-side petcock? Petcocks affect cylinders 1-2 and 3-4. Coils affect 1-3 and 2-4.
Sounds like a fuel delivery issue.

[Dennyz]

On all the XSs I have owned, coils affect 1-4 and 2-3.

Coils affect 1-3 and 2-4.

[trbig]

I agree.... it sounds like fuel related to me also. Have you tried running it with the petcock on the right side in the "Prime" position?
I also have had needle valves stick from old fuel in a boat motor... could try tapping on the carbs with the handle of a screwdriver... but seems suspicious that it's on 2 carbs that the same fuel line feeds.

Good luck and welcome to the forum.


Tod

[TopCatGr58]

Hey Tranger,

I, too, concur with the general consensus here, it's fuel related! Your 78 has the vacuum actuated petcocks. Make sure they work, by unplugging them from the carbs, and then apply suction to the suction line to ensure they flow!

Secondly, like Todd said, put the right one on PRIME, it should flow without the need for engine vacuum! Make sure it flows, then you can connect them back to the carbs.

Check the "T" fitting for that pair of carbs, folks clean the carbs, but forget to ensure that the "T" fitting is open, can also get clogged and prevent flow.

Also, make sure your upper "T"s are properly vented, they are NOT to be capped off! Hang in there, you'll get it!
T.C.

[tranger03]

almost there, i hope

okay, i ended up hoking up an auxilliary fuel tank so that I could more easily reach the adjustment screws. Tcat, I checked the petcock on the fuel tank and it seemed to be working fine. Anywho, the bike is running better now but I am still having a couple of problems.

1. The bike will not idle on its own ( I either have to be giving it throttle or have the choke out) this occurs even after the bike is warmed up.

2. Are the any starting points I could use for the master adjustment screws and the other enrichener screw. It doesn't seem to want to respond to any adjustments made.

Also, I checked the enrichener needles and none of them had a broken tip. I believe that my next concern should be to get it to idle on its own and then I can synch the carbs. However, I am not sure where to begin trying to get it to idle.

Note: All four cylinders are now firing. :-)

Thanks for your replies.

[jmaechtlen]

simple stuff to try

Isn't there a setting for idle speed?
can you set it up a bit so the bike will keep running, then play with idle mixture screws?

(I ass/u/me that you have a good fan set up to cool the motor while running it and making adjustments?)

Can turn each idle screw in to stop (gently) and count the revolutions of each.
That will give you a general idea?
On my XS750, they are about two full revs out.
I forget- did you pull them out yet and blow any cleaner into them? If not, you can try it.

cheers
Jay

[TopCatGr58]

Tranger,

Firing on all 4 is a good sign, so now you know you're at least getting "SOME" fuel into the system. You've only cleaned them once, as you may have found, many folks find they have to do it 3 times to get them thoroughly clean. The pilot circuit is particularly difficult to clean out.

The stock settings for the Pilot screws are 1 & 1/2 turns out from a gentle seat. You've verified that the tips are not broken off!

Have you done a compression test? Also, have you done the cam chain slack adjustment? Have you checked the valve clearances?

Since you need to keep the throttle/butterflies open a touch to keep it running means you may just need to adjust the main center idle screw until it will idle. Then you can do a preliminary vacuum synch. Then you can run the bike a while with SEAFOAM in the tank to further help clean out the pilot circuits, IF you don't want to go back into the carbs

Then after a tank of gas, the pilot circuits may be cleaned up enough to then allow you to make some fine adjustments in the PILOT SCREWS, and you should then be able to get some responses from adjusting them.

Ken Talbot recently posted a great reply on how to perform an AUDIBLE style of pilot screw tune vs. using a Color Tune system.
T.C.

[tranger03]

nothing happens

T.C. I tried to mess with the master adjustment a bit and no matter which way I turned it I could still not get the bike to idle without the choke being out or giving it some throttle. Does anyone know which way I should turn it to increase the idle speed? Plus I have a couple of more questions.

1. If the airbox is off will that make it run too lean and therefore it will run with the choke on?

2. Since I am currently using an auxiliarry tank to perform these steps, should I plug the vacuum lines that would normally go to the petcocks or just leave them open? Because I did notice that the idle rpm's increased with them plugged.

I am so close i can taste it, if I only knew more about these carbs. Thanks again for the tips.

[randy]

Tranger,

Hook up your mercury stick, don't wait for the right moment 'till it warms up. You're flying blind. The stick will help guide you as to what adjustments you need to make to keep it idling. JUST DON"T BLIP THE THROTTLE WITH THE STICK ATTACHED.

Turn the idle stop screw clockwise to raise the idle. And, YES, plug the vacuum lines if you have nothing attached, they let raw air in to the manifolds and leans out the mixture.

Set up the intakes as they will be when you are running, in other words, install the airbox and filter. Doing your adjustments without them will be a waste of time if you then install the airboix later. You'll have to do all of the adjustments again!

[pathfinder]

tranger03, welcome, I have a 78E also and have found that it is not possible to do a bread tie sink untill you remove the spring from the idel adjustment screw. Remember #3 you can't adjust, you must set 1 & 2 equal then set to #3 then number 4 to #3. After your done pre-sinking remember to reinstall the spring before you install the carbs. Like TC said set your "Pilot screws are 1 & 1/2 turns out from a gentle seat." After you reinstall the carb rack hook up your auxillary tank (gravity fed). The idel screw at the rear of the carbs is to the right to raise the idel. As you adjust the carbs with the sticks you will have to lower the idel a few times to get it right. Remember there is no correct vacume setting on the sticks, they just need to be equal.