the drama never ceases

[xsivelybad]

Ok... so we got the xs1100 midnight special and got it up and running...Today i had my first fun electrical problem. the headlight decided it didn't want to work anymore so i cleaned the conections in the handlebar housing and both blinkers began to work...still no headlight. So back to the fuse box i trudged cursing the damn thing like a sailor as i pulled out yet another blown fuse. Everything works fine now but still having a unrelated issue and looking for help on it. My bike runs beautifully except for the ancient carbs. I start it up and it backfires spits and sputters from time to time, that i can deal with. Unfortunately, it occasionally decides to rev up to about four RPMs and I haven't been able to determine why. I have cleaned those carbs 1...2...3..count em' three times and to no avail. anyone have an idea why the damn thing idles up so high sometimes and other times stays at an acceptable level? I am headed to work but i will check the forum later in hopes of an answer to my delimma.
Thanks
GREG

[skids]

Re: the drama never ceases

I am guessing that a float is sticking at the hinge, or a fuel valve's pin is occasionally sticking.

Originally posted by xsivelybad
I start it up and it backfires spits and sputters from time to time, that i can deal with. Unfortunately, it occasionally decides to rev up to about four RPMs and I haven't been able to determine why. anyone have an idea why the damn thing idles up so high sometimes and other times stays at an acceptable level? I am headed to work but i will check the forum later in hopes of an answer to my delimma.
Thanks
GREG

[pggg]

For a start set the butterflys with either a razor blade, an .025 feeler gauge or preferably by eye. (1/2 cover the front fuel pinhole.) All floats set exact. All jets matching brands and sizes. All float valves in good nick. All idle mix screws in good nick and set exact. (better slightly rich than lean) Occasional high revving equals sticking throttle cable.

[TopCatGr58]

Hey Pggg,

I'm with you in thinking he's got a sticking throttle cable. Best to pull it OFF, and spray some lube in it, and slide it in it's sheath, and check for any kinks, or where it might be hanging up. Also, pull apart the throttle handle, the lube can get gummed up in there, and make sure the cable isn't catching on anything in the hand throttle grip channel. Also check where the throttle plate is moving next to the intake tubes, the clamps sometimes rotate, and get in the way of the throttle plate rotation!?
T.C.

[xsivelybad]

thanks everyone for the generic feedback. I think i am going to have to sit down and tune those carbs i've just been busy. I wasn't sure if the carbs being off tune could be what is causing it or if the throtle cable had something to do with it...by the way the throttle cable was my first guess
Thanks again hoping for more feedback....
Greg

[GNEPIG]

.. ok, i will take a stab at the generic feed back thing
. if all the suggestions of these other fine people do not work for you, then try taking the pick-up coils off the end of the crank, behind the part that rotates them, is a centrifical advance mechanism that doesnt work untill after 3000 rpms, check this part to see if its sticking or worn out.. it might just need some lube
there is a test in the service manual for the proper operation of this part -
follow those instructions and it will tell you if its bad or not advancing correctly
.. you will need a strobe light for this

[Dadroid]

I have worked on that bike with Greg, we cleaned those carbs three times, (not on purpose, they just kept needing it...lol)
And we adjusted them as best as two shadetree mechanics can, without a manual, used alot of info from here.
The throttle cable is not sticking.
The bike will be sitting at idle, and nobody touching it, and all of a sudden it will idle up to 4 or 5 thousand RPMs sometimes stays there, sometimes idles back down, still with no one touching it....its the darndest thing to see...lol
About the only idea that we have heard that might make sense is that we idled it with only two sparkplugs firing, and sometimes the others kick in....(yeah it don't make that much sense...lol)
Beyond that the carbs seem to be working well on the other jets, runs like hell....
Any other idears we can play with?

[pggg]

Sounds like either the tank breather is blocked or the fuel taps are playing up.

[Dadroid]

Thanks Pggg,
Now if you don't mind explain more.
Where and what is the tank breather?
I never saw anything that I thought was a breather on the tank, is it in the cap?
As for the fuel taps?...Not sure I understand that term, are they the same as the tank petcocks?, they do not work right, we put cut offs in the fuel lines, until the rebuild kits came in.
Sorry to be a dumba**.
Tthanks
Droid

[TopCatGr58]

Hey Dadroid,

The "vent" is built into the gas cap, when you open it, on the underside, you'll see a little pinhole, that's the vent, there's a little disc that is in there, and it can get gummed up and stick, blocking the venting action, you just take the cap apart, and clean it similarly to the carbs!

However, now that you mention about the petcocks, and that it sometimes is running on 2 cylinders brings more light! Are you also still running the Octopus? And with it being an 80 MNS, it had the brass caps over the pilot screws, were those removed for the cleaning? If not, then the pilot circuit really isn't as clean as it should/needs to be....sorry, but that could also be the intermittent flow of fuel cause?! Either bypass the Octy, or use PRIME, and pull the hoses off the petcocks and test to make sure the fuel IS FLOWING thru the spouts on PRIME! The petcocks have filter screen towers inside the tank that can also get gummed/clogged.

You need to get it consistently running on all 4 cylinders, then once you do, it may be that the main idle screw is just set too high....needed to keep it running on 2, but too high once the other 2 cylinders kick in??

SO....regrettably you may need to clean them again if the pilot screws(not just the pilot jets) were not removed to thoroughly clean the pilot circuit...but look at how well you're learning how to remove and remount them!
T.C.

[Dadroid]

Thanks for the advice, please keep it coming.
The bike is in Orlando with Greg right now. It is his bike, I am just helping.
I will make sure he checks back on this thread.
The caps were gone from the pilots, they got cleaned.
The vent we will check and I think we will pull that stinkin' octopus out....lol....Hobbit already told us to do that and we didn't...Just gravity feed.
Oh the "runniing on two", don't know if that is accurate or not, I know we HAD all 4 firing, but they might be intermittant again, that is just another of the theorys here.
Later Droid

[missinglink]

Here's my .02 worth. Did you check the choke circuit? I know on my bike if I have the choke on full the bike will rev to about 3k after it warms up a little.

[Dadroid]

Well it doesn't really have choke does it? From my reading its an enrichener, like on a big twin, that simply pumps a bunch of gas right in, not like a standard butterfly choke that cuts down on the air...if I am wrong, please correct me, I am still learning about this bike.
Also what I said before still stands,
"The bike will be sitting at idle, and nobody touching it, and all of a sudden it will idle up to 4 or 5 thousand RPMs sometimes stays there, sometimes idles back down, still with no one touching it....its the darndest thing to see...lol"
This wouldn't happen this way if I simply forgot to push in the enrichener, or am I missing something (which I do often..<grin>)
Thanks
Droid

[prometheus578]

I like your thought about running on two, and then kicking to four. Fire it up and let it warm for a few minutes. spray the header pipes with water. (I use a spray bottle of 409 for convenience) If you have a dead cylinder.. the pipe won't sizzle. For intermittent firing.... the bad cylinders won't sizzle like the others.
If indeed you have the idle set when running on just two or three.... you should have some bad sizzlers. When the idle kicks up to 3,000... check again... all four would be sizzlin' about the same.
Yes, we have enricheners... extra boost of fuel.

[Chaluska]

sounds like it may be a vaccum leak (sorry i havent read much of the post.. it may have already been posted)