Cold #1 &2 Pipes, rough at low speed

[warlock60]

Gents,

'79 XS1100 Special (Awesome Ride when its right!)

Recently returned from an 18 month Central American tour. Drained tank and carbs prior to departure and after starting the bike every time I returned home for a visit.

The bike would not start and stay idling without some thottle so I put in new (hotter) plugs. Bike started and idled nice. Took it out for a drive and found that in the high end it runs fine, but by the time I got back the bike ran rough at the lower RPM. Initially before I changed plugs the #1 and #2 cylinders pipes were cold.
--The new plugs for the #1 and # 2 cylinder after I coasted into the driveway were sooty and wet.

So the question: can this be a sync problem between banks of carbs- 1 and 2 running way too rich? Or, am I forced to clean the carbs? Or, is there something else that may be amiss?

Compression is OK.

[TopCatGr58]

Gimme that ol black soot, errr....magic!

Hey Warlock,

Draining the tank, carbs isn't as good as putting in fuel stabilizer, or better yet, carb cleaner, like SeaFoam, or B12, Techroline, etc.!

You've probably got clogged up pilot circuits=poor low rpm response. Also, your floats and needle seats may not be sealing properly, due to gummed up, or crud from tank, etc., causing a flooding condition in those carbs, again poor performance.

Easiest thing will be to put in some SEA FOAM in the tank, about half a can, and run it a while to get it mixed in with the fuel, and down into the carbs, then let it sit a while in the carbs, and then run it again till you empty the tank, and then put more fresh gas and more SeaFoam in and repeat, but you should probably notice an improvement after/during the first tank ful.

IF NOT, then you are probably going to have to pull the carbs for a more indepth cleaning and replacement of float needles and seats/seals! Doubtful that it's the synch!
T.C.

[warlock60]

Thanks TC! Bought The Seafoam and put it in - I'm sure it will help.

I the meantime I put a voltmeter on the battery and found 16volts! Hummm!? So I bought a new battery, apparently you can't get 4 years out of a $40 dollar battery Started thinking that with the bike running high RPM producing full electrical power then coasting into the driveway with a defaulting battery maybe that had something to do with it - it did.

Secondary: found that my son was riding it while I was away and wife put bike in back shop after smell of gas in garage. Found crank full of gas/oil mix, mostly oil. Pulled carbs, built carb holder (thanks for the tech tip Rick Jemison & Ken Talbot). Found carb level to be at bottom of screws (used brake bleeder valves at drain with clear tube)- think they are good. So put carbs back on ordered new needles and will replace when they arrive. Until then will turn off petcocks with engine off - WILL TELL SON TO DO THE SAME! ( 'cause bike goin' back in garage!)

Changed oil, adjusted Clutch, lubed cables and hey,

bike runs like a dream.

Thanks
Ray

[knewsom]

So uh, don't flame the noob, but what exactly IS the so-called "off" position? "PRI"? Becasue when my tank is off my bike, "PRI" won't let any fuel through, but "ON" dumps it out.

[TopCatGr58]

Hey "KNEWBY",
Are you sure you're reading your petcocks correctly? The function is when the large handle is covering or pointing in that direction! Prime should be free flowing, and ON, should only flow when vacuum applied! So....ON is the Standards OFF! You may need to repair your petcocks??
T.C.

[knewsom]

Originally posted by TopCatGr58
Hey "KNEWBY",
Are you sure you're reading your petcocks correctly? The function is when the large handle is covering or pointing in that direction! Prime should be free flowing, and ON, should only flow when vacuum applied! So....ON is the Standards OFF! You may need to repair your petcocks??
T.C.

noooooo! I just bloody reinstalled them!!! I have a WHOLE TANK full of gas!!! aaaaghhhhhh!!!!! Dude, I don't know how many more things I can fix/replace before I have an ENTIRELY NEW BIKE.

*sigh*

[knewsom]

let's get this straight:

PRI should be FREE FLOWING, from the main nozzle, yes?

ON should only flow when there's a vacum on the vacum nozzle, yes?

And Res should be the same as ON except that it works when there's less gas in it??

What does it mean if when I have it set to "PRI" nothing comes out?? Maybe they're just switched...?

[GNEPIG]

.. it is possible that someone has switched the face plates. put a vacuum on it and see if the fuel comes out in the prime position. if so switch the plates and see if they work the way they should
..i have a mixed-up set like that on one of my bikes

[knewsom]

If that IS the way it is, then I think I'll just leave it be, and only switch it to ON if I want to prime the engine, and use PRI as my "on".

well, I'm goin out with a vacum hose right now - gonna suck on it and see what happens!

[knewsom]

And yea, I placed the vacum tube on the nozzle, and brought forth the other end unto mine lips, and thence I did suckle.

And gas flowed like mana from the petcocks affixed soley in the "PRI" position, and there was much rejoicing.

Amen.

[skids]

On the standards, pointing the handles forward is reserve, to the rear is prime, down is automatic on. If your face plates are OK the way you installed them, check to see if the handles weren't installed on the wrong sides. They are not interchangable. I think there is a mark inside the center of the handle on one of them to indicate the proper side and the other can be figured out by elimination.

Your tank is full of gas? You had better start riding! :-)