4500rpm power hits!

[BGJohnson]

Ok, so found out a few things.

#1 is super fat.

So I spaced 2,3,4 up a groove from factory and #1 I spaced down one from factory. Bike responded much better.

Why is #1 so darn fat? Would an ignition miss cause that?

[BA80]

It could be a lot of things but adjusting one carb that much differently than the other three would suggest that you need to check out the carbs, especially #1, more closely.

My first experienced intuition would be a float height issue or emulsion tube that isn't clean enough.

[BGJohnson]

Well, when I was taking it apart I grabbed the top of the emulsion tube, that little hood got a little bent, I thought I bent it back.

So just got done with testing. 2,3,4 are still 2nd notch from the bottom. #1 is now the very top notch. The 4k stumble at cruise is gone, it feels strong. 2k is a bit softer, there is still a little stumble, but with pod filters, I bet I won't get rid of that.

Pulled the plugs, they look far more even now.

But I'm assuming I should replace that emulsion tube?

[skids]

Don't grab the emulsion tube by that hood thing. Unscrew the main jet and push it up from the bottom. Clymers was wrong there!

[BA80]

I'm not sure that little air dam would cause this but anything is possible.

I had a stumble on acceleration and the little uneven power at cruise when I first did my carbs too. Also, the plugs were sooty. I found that it was the after market pilot and main jets and some dirt in the emulsion tube wells.

Put the original (genuine Mikuni) pilots and mains back in and cleaned the emulsion tubes and wells really good an I pretty much haven't touched the carbs in about4 - 5 years.

[motoman]

Don't grab the emulsion tube by that hood thing. Unscrew the main jet and push it up from the bottom. Clymers was wrong there!

.........or if its initially hard to push out(cleaned, slips out easily), wooden dowel or cheapy Bic pen tube(ink tube removed) used as a punch without damaging brass works good.

[BGJohnson]

I think my next step is to take the carbs apart again and make sure nothing got in that emulsion tube orifices.

Everything was spotless when it went back together. I have been using fuel filters when I rebuilt everything.

4k rpm was soft before, but it didn't misfire like it did this past weekend. It was a little colder out though. I'm just going to ride it for a little bit longer and see how it changes with warmer weather.

[motoman]

Bettin' your supposed carb issue is ignition related. Ignition on, check voltage at coil input. Check coil ohm resistance across pri. sides of coils. Pull ignitin cover and pull on pick-up coil wires every inch looking for stretching in insulation(broken wire internally). Ballast resistor is another known issue point. Likelyhood of your carbs having an ignition issue is highly suspect.

[BGJohnson]

It's an easy thing to check. Might as well!

[motoman]

It's an easy thing to check. Might as well!

.......may be surprised what you find.......or lack of.

[jetmechmarty]

I run my carburetors stock. I'm sized up just a bit on the mains in the middle. I have a stock airbox and some 4 into 1 exhaust I have never identified. Power comes on strong a little over 3000 and continually increases to some place well beyond 5K. I get no power surges. I may be just a bit rich on the floats. My plugs stay light tan. I get 28 to 32 miles per gallon on whatever gasoline I feed it.

I believe it runs like it's supposed to. It feels like any other well tuned XS11 I've had the privilege to drive. I don't believe I understand all the messing with jets and needles I keep reading about.

[BA80]

The 80 and up engines have a pretty flat power curve. Smooth and strong through all ranges. The older engines have that burst that'll surprise the daylights out of you if your not ready for it. I'll let you try my bike next time I see you Marty and you'll see what I mean. You could just try Jeff's bike and see. The 78 is even quicker than the 79.

It's a difference in the cam grinds and timing curves.

[jetmechmarty]

Greg,

I rode Jeff's bike a couple of times and it runs perfectly. It comes on very strong over 3K and keeps on coming stronger and stronger. I know what you mean, but when I read these descriptions of warp drive, I usually assume it's a poorly tuned or broken machine. For those of you who don't know, Jeff has a XS1100E.

[BGJohnson]

Well I've put more miles in it, it's breaking up again 3500-4500 still. I checked out the ignition pickup wires and they are perfect, wiggled, jiggled, pulled on them. Runs the same.

I'm going to just have to tear the carbs apart again. I was going to put stock pilot jets in and put the needle clips back to stock position.

[motoman]

Well I've put more miles in it, it's breaking up again 3500-4500 still. I checked out the ignition pickup wires and they are perfect, wiggled, jiggled, pulled on them. Runs the same.

I'm going to just have to tear the carbs apart again. I was going to put stock pilot jets in and put the needle clips back to stock position.

Good choice for a baseline. If no change, and you know for sure their's no 'science project' still exist in carbs, and voltages TO coils(pri. ign.) is 12+volts key on, secondary ignition issue still exists somwhere.