cold headers

[CatatonicBug]

I did not dunk anything, as I don't have a dunk tank. I do wish I had an ultrasonic cleaner, but that will have to wait a while. I have read in several other threads that dunking carbs will destroy the butterfly seals. Is that what you are referring to? I am hoping that I don't have to deal with that issue.

The old idle needle screws all came out very nicely. No tips left in the holes. I screwed the new ones all the way in and saw the tips of each as they emerged into the carb body. I then backed them out 2.5 turns. That's the default setting, isn't it?

I will pull the carbs again (getting good at that) and put the o-rings in. Thanks for that info. If the spark plug has black stuff on it, does that make it fouled? In past experience with plugs, I could always just take a wire brush to them and clean them up as long as there was no carbon traces on them. Is that not true here?

[boyat68]

"I know I need to sychronize, but that will be the finishing touch after I get everything running the way it should be. My neighbor has the synchronizing rig, but I only want to have to do it once, after I am done with everything else."

I have found that you have to do a synch as soon as you install the carbs in order to get the individual carb all pulling at the same level. You may have to do the synch a couple of times in order to get the idle speed in the ball park. This alone will probably eliminate the difference in the heat/cold of the pipes. The real seceret is getting the same vacuum pull on each carb.

[prometheus578]

"Fouled is fouled."

If the spark plug has black stuff on it, does that make it fouled?

Yup. Carbon fouling.
Taking a wire brush to the tip... only cleans the tip. Fouling also extends down the insulator cone... the place that you can't clean.
Now... if the "Electricity God" deems that it's easier for the juice to just run down a carbon track on the insulator cone instead of sparking across the gap... that's his choice, not yours.
You'd be surprised how many times an engine perks up with new plugs.. after replacing the marginal(or "cleaned") old ones.

Never work on, nor trouble shoot, a bike until you put in new plugs.
You'll tear apart the carbs... rewire the ignition... just to find out it was a faulty sparkplug all along.

EDIT:
Actually, some times you can get away with just wire cleaning the plugs, and eventually the running engine will "self clean" the plugs the rest of the way.
But, if you have a bike that's running poorly, well... read what I wrote above.

[cywelchjr]

My rebuild included most of what you mentioned. I replaced all of the parts included in this rebuild kit, except for the small round silver plug thingy (center right) and and the tiny o-ring next to it. I couldn't figure out where these go.

Only things I didn't do was separate the carbs from each other and remove the butterflies.

I was sure to spray carb cleaner through each and every port and made sure it came out the other side. The plugs are relatively new, as I replaced them in October right after I got the bike. I will try swapping them around to see what happens.

I know I need to sychronize, but that will be the finishing touch after I get everything running the way it should be. My neighbor has the synchronizing rig, but I only want to have to do it once, after I am done with everything else.

I don't know how your pipes are laid out, but mine put the outer cylinders on one side and the inners on the other. The outers are hotter than the inners, which I believe means richer which fits with stock jetting although I haven't checked it yet. I also get more vapor out of one side when cold, but I think it once again fits with stock jetting. It's possible depending on your header layout that this might just be normal? Then again it might not be. Of course mine needs a good bit of work because of the POs which I'll mention in the PO thread.

[CatatonicBug]

Ok. I will look for new plugs tomorrow. I just went through the idle needles and put in the new o-rings. Turns out, the old ones were still in there. They weren't o-rings - more like flat rubber washers. Put it all back together again, swapped the spark plugs around, and the problem still exists...

I did determine that the heat turns on when I raise the RPMs though. When at idle (approx 1100 RPM), I was able to remove the wire from plug #4 and nothing changed. As soon as I touched the throttle with the wire removed, the engine died. I would say that means there is something wrong with the idle circuit.

Other than new plugs, what's the next thing I should try?

[CatatonicBug]

I don't know how your pipes are laid out, but mine put the outer cylinders on one side and the inners on the other.

You've got a funny layout there... Mine are the stock headers, which puts 1 and 2 out the left side and 3 and 4 out the right side. No swapping or re-routing of the pipes here.

[CatatonicBug]

I feel kinda silly now... One of the reasons I knew I had to rebuild the carbs to begin with is that I coud not keep the bike running without keeping the choke pulled out all the time. With all this testing and stuff, I kept the choke pulled. Just now, I went out and started it again and pushed the choke in. It stayed at idle, with only a slight drop in RPMs that recovered after a few seconds. I then let it idle for a bit. Immediately, I noticed that the sound coming out of the left tailpipe was different. I sounded smoother and more powerful. After a minute or so, heat actually started coming from both tailpipes equally!

Now, I am not sure exaclty how the choke works with 4 carbs, so I don't know if a combination of the choke and a need for a syncronization could have caused this, but it sounds nice now, and all 4 headers heat up as long as I keep the choke pushed in.

[Ivan]

carboned plugs can be salvaged by burning them clean with a propane torch.

Like Prom said, you need good plugs to trouble shoot with. A new set may help.

Cleaning the plugs with a torch will work when the engine is running strong, as they will self clean the rest of the way. This also works with fuel fouled plugs, where they are wet with gasoline. You'll know they are clean when the tang glows red and the flame coming from the plug doesn't change color from the blue color of the torch.

[prometheus578]

You ain't the first, Catatonic..."

What the choke does is....
Actually, it doesn't choke. It's an "enrichener".
When you apply "choke", those plunger thingies on the carbs open up and raw, unmetered fuel pours into the carb throat.
Actually, it is metered... fuel gets sucked up from that brass tube that sticks down into the float bowl. You 'member seeing it when cleaning?

So, like you can guess... the bike ran badly and the plugs fouled... by you leaving the "choke" on.

Of course... everyone needs the experience of cleaning their carbs.. so it was a good exercise for you, though an excercise in futility.

Things should be all sorted out now.

heat actually started coming from both tailpipes equally!

A better way to check exhaust heat... get a spray bottle of water(I use a bottle of 409 cleaner) and spray the header pipes. Whichever one doesn't "sizzle".. that's the dead cylinder.

[CatatonicBug]

What the choke does is....
Actually, it doesn't choke. It's an "enrichener".
When you apply "choke", those plunger thingies on the carbs open up and raw, unmetered fuel pours into the carb throat.

If you think about that, it actually IS "choking" the engine. It's limiting the flow of air that mixes with the fuel. I just wasn't sure if there was some kind of special manipulation of the fuel flow that was different from one carb to the other in this system. I've only ever dealt with engines with a single carb before, so having this setup is relatively new to me. Just trying to figure it all out.

I am glad I got this figured out today though. Thanks for everyone's input!

[skids]

Well as long as you got if figured out... But Prom is right. The "choke" on the xs11 is an enrichener. It does absolutely nothing to meter the air. Nothing.

If you think about that, it actually IS "choking" the engine. It's limiting the flow of air that mixes with the fuel. I just wasn't sure if there was some kind of special manipulation of the fuel flow that was different from one carb to the other in this system. I've only ever dealt with engines with a single carb before, so having this setup is relatively new to me. Just trying to figure it all out.

I am glad I got this figured out today though. Thanks for everyone's input!

[prometheus578]

Not really limiting the flow of air... but richening that flow of air with more fuel.
When you pull the "choke" lever... that long rod pulls back and opens the "Choke" plugers on all the carbs.

[CatatonicBug]

Hmmm. Ok. I stand corrected. Thanks for the info.

[tarzan]

If you think it runs good now,just wait and see how it is after a sync and proper idle adjustment.It makes a big difference.Glad you figured it out.

[Larrym]

Just got done isolating a problem on my bike where the problem wasn't the carbs. Ended up being that the #1 spark plug cap was never fully screwed into the plug wire.

To isolate the problem I ended up building a seperate carb bank which I swapped out with the originals. Problem was still there so I moved on to the ignition system.

If all efforts to locate/repair "problem" in carbs fail then PM me. "Test" carb bank just sitting around waiting for the fumes to dissipate enough for the spiders to move in...