I am stumped

[79XS11F]

My restored 79 XS11 Standard is not running right. It is missing at idle, during acceleration, and at any held speed in any gear. She pretty much is running on 3 cylinders with # 2 appearing to be where the issues is.
To date I have:
- Cleaned the carbs about 5 times including putting parts and bodies through an ultra
sonic cleaner.
- Confirmed float levels as within spec (set all at 1 inch)
- Confirmed that the fuel tank air intake is working.
- Used new gas.
- Confirmed that the petcocks are working properly.
- Confirmed that the coils are good by installing a set of excell coils from my other bike.
- Confirmed that the pick up wires are good.
- Confirmed that the timing is good.
- Confirmed that the ignition unit is working by switching it out for a known good unit from my other bike.
- Sprayed quick start around carbs while idling with no change so no air leaks.

The bike still will not run right. I think I will give her a complete tune up and carb cleaning again but I am not holding out much hope that this will result in a running bike.
She ran very well for 2 years after being restored. The 3rd spring she developed this issue and I have had no luck sorting her out. Any suggestions would be appreciated. I must be missing something and maybe it s so obvious I can see it.
Rob

[D0wn5h1ft]

My restored 79 XS11 Standard is not running right. It is missing at idle, during acceleration, and at any held speed in any gear. She pretty much is running on 3 cylinders with # 2 appearing to be where the issues is.
To date I have:
- Cleaned the carbs about 5 times including putting parts and bodies through an ultra
sonic cleaner.
- Confirmed float levels as within spec (set all at 1 inch)
- Confirmed that the fuel tank air intake is working.
- Used new gas.
- Confirmed that the petcocks are working properly.
- Confirmed that the coils are good by installing a set of excell coils from my other bike.
- Confirmed that the pick up wires are good.
- Confirmed that the timing is good.
- Confirmed that the ignition unit is working by switching it out for a known good unit from my other bike.
- Sprayed quick start around carbs while idling with no change so no air leaks.

The bike still will not run right. I think I will give her a complete tune up and carb cleaning again but I am not holding out much hope that this will result in a running bike.
She ran very well for 2 years after being restored. The 3rd spring she developed this issue and I have had no luck sorting her out. Any suggestions would be appreciated. I must be missing something and maybe it s so obvious I can see it.
Rob

Sounds a little bit like you might have a rusty valve from sitting over the winter just from the timing and that nothing has changed between riding seasons. If you didn't start the bike for 4-6 months it's possible that the valve that was exposing your cylinder to air maybe rusted. If so, it probably isn't closing properly resulting in a lack of compression.

Grab a compression tester and test each cylinder. The holy trinity of an engine is spark, fuel/air, and compression. So, if you're convinced it's not spark or fuel/air then it must be a mechanical problem with your engine. Just some food for thought.

[WMarshy]

Compresion check and also a leak down test would be my next move.

[motoman]

Since you indicate it DOES set for a period of time, I would first suspect a 'science project' was taking place in the carbs from the fuels of today.
The seemingly first place that affects is the pilot circuit, specificly the pilot jets. The teeny-tiny atomizing hole in end of those jets get plugged. Any black 'goo' gets drawn into those pilot jets, and cannot escape, just plugs up or restricts the atomizing hole. Carbs need to be taken apart, including the slide so the emulsion tubes can be removed and cleaned also. Use a tooth-pic, nothing metal to clean all the little sideholes of the emulsion tubes AND pilot jets. Inspect the inside of those pilot jets with a magnifying glass and good light. Be surprised what you'll see hung up down inside them.

[79XS11F]

The gas that came out of the carbs was translucent green. Like mountain dew soft drink color. I never seen this before but in any case the carbs were fully disassembled and cleaned by hand as well as in an ultra sonic cleaner. Than all passages were blown out with compressed air. All galleries were free flowing. I'm going to clean them again along with a full tune up but I still think I'm over looking something else. Something simple.
I will run a compression test as part of the tune up.
The bike has been stored in a heated garage so it has not be exposed to damp conditions.
Keep the ideas coming. I really want this sorted out so I can catch the end of our short biking season.
Rob

[BA80]

Possibly the fuel inlet T is plugged and #2 carb isn't getting fuel? Is the plug wet?

Also, there is a passage between the main jet well and the pilot jet well that can get clogged and it'll miss until you open up the throttle and put the main circuit into play. BTDT both issues.

Here's a couple pics of the passage I'm speaking of with a sewing needle in it to make it easy to see.

[hamjam]

remove the Spark Plug Cap cut a 1/4 inch off the wire and re thread it on
you may have a compromised wire end ,while you have it off check the resistance
http://www.xs11.com/forum/showthread.php?t=5954

[motoman]

The gas that came out of the carbs was translucent green. Like mountain dew soft drink color. I never seen this before but in any case the carbs were fully disassembled and cleaned by hand as well as in an ultra sonic cleaner. Than all passages were blown out with compressed air. All galleries were free flowing. I'm going to clean them again along with a full tune up but I still think I'm over looking something else. Something simple.
I will run a compression test as part of the tune up.
The bike has been stored in a heated garage so it has not be exposed to damp conditions.
Keep the ideas coming. I really want this sorted out so I can catch the end of our short biking season.
Rob

Same happened to my Venturer when I got peod at it and left it covered in corner of mancave for a year.......translucent green lookin' fuel when draining everything.
Seriously though, pay specific attention to the pilot jets, inspecting WITH a magnifying glass. YOur gonna have to litteraly soak float bowl pins, metal ends of floats, metering rods, ALL jets and emulsion tubes in laquer thinner, then physically wipe down float pins and metering rods with a laquer thinner soaked rag to remove that sticky, invisible crap.
Carb cleaner spray, not even Berrymans Chemtrol-12l will touch that stuff.....DAHIK.

Lol.......fooled all of ya's on the diagnoses this round......O...Hi! W.Marshy..........stick around......never know which way I'm gonna go!

[BA80]

He's got a 79 Brant so the floats will be brass and it's the brass that turns green. All the brass parts in there will be green and nasty.

Rob, you'll have to completely disassemblt those carbs and like Brant said, ceck and clean everything. Don't forget to remove the emulsion tubes (needle jets) and the pilot jets and clean them and their respective gallies. Pay particular attention to the idle mixture ports and the 3 tiny holes on top behind the butterfly valve. These are VERY important.

[motoman]

He's got a 79 Brant so the floats will be brass and it's the brass that turns green. All the brass parts in there will be green and nasty.

Rob, you'll have to completely disassemblt those carbs and like Brant said, ceck and clean everything. Don't forget to remove the emulsion tubes (needle jets) and the pilot jets and clean them and their respective gallies. Pay particular attention to the idle mixture ports and the 3 tiny holes on top behind the butterfly valve. These are VERY important.

Actually Greg, the fuel IN THE TANK turns green........I'm sure initially dis-assembling the carbs, all the brass pieces were starting to show green in places too. Like you said, adding in the importance of 3 tiny ports in venturi being clear and open FULLY is at times overlooked also

[BA80]

Actually Greg, the fuel IN THE TANK turns green........

Hmmmmmmm........don't recall ever seeing that before.

[motoman]

Hmmmmmmm........don't recall ever seeing that before.

Yup......no real smell that even resembled the turpintine smell you used to get from stale fuel decades ago. Settin' on a trash can draining the tank on prime it definitely had a green tint to it.
Which is what 79XS11F needs to do, or he's right back to square one.

[WMarshy]

Lol.......fooled all of ya's on the diagnoses this round......O...Hi! W.Marshy..........stick around......never know which way I'm gonna go!

Must be something in that Colarado air your breathing.

[BA80]

Must be something in that Colarado air your breathing.

Rocky Mountain HIGH.

[skids]

OK, so I say that Brant wins with his "science project" assessment. Personally, I would try the carb spray technique before tearing the carbs off of the bank-'o-carbs. This is seriously easier and I have had great success with that. No need to remove butterfly shafts and no need to cuss God while you separate the carbs from the bracket! (I have begged forgiveness!)