poor /erratic running off idle

[jkgrubbs]

I recently purchased a 1981 xs11 midnight spec. Wondeful bike, garaged and all, but I have a probelm. Between 1500-2800 rpm itchokes down, as if two cyls go to the Bahamas, above 3000, everone reports for duty. The advance plate shakes when you look at a it with the cover off, the carbs have been doen it has a Kerker, i do not know if it has been rejetted, the wires at the advance/pickup seem good, I suspect a vaccuum leak

Any Ideas?

[strom]

Replace the vacuum hose, they're inexpencive and easy to replace, check spark plugs and replace (one should do this anyway when buying an old bike), also check the ignition unit if u can... inspect the springs behind the pick-ups... clean the carbs and check the jets. Inline fuel filters also help preventing any small particles getting stuck in the carbs.
However, check the plugs 1st.

LP

[nashville_bill]

Similar Problem

I have a similar problem on a 1981 daylight special. I installed the fuel filters to keep the sediment out of my carbs. I also have a 1981 XS650 and the fuel petcocks and hose is very simple on it. I may try to get a couple of XS650 petcocks and install on the XS11 tank. They are vacuum operated. The bike would only have two fuel hoses and two vacuum hoses and would be much less cluttered.

Please let me know what you find to fix your problem.

Bill

[Jdwags]

stutter at 2500-3000

I have had the same stutter with the Mongrel since i got her, along with another one up at about 5k

same wiggle of the vacum advance too.



until Sunday afternoon, thanks to the brain twisties of Mike Hart, who suggested i pull the customized air filter from the PO, as it might be starvin for air...

Well I did, and its a NEW bike... no problems anywhere.. its awsome..

Check your air filter, clean ? properly placed, not blocking anywhere?

Hope this helps, just a thought

[rockyr74]

petcocks

In regards to petcocks, I removed the whole damn octopus assy n and run one line from the front tap of each petcock straight to its adjacent set of two carbs. (80 special)

I put a hose plug, like used to block vacuum lines on cars, over the unused rear petcock tap.

I swing the tap levers straight forward for off and straight back for run. I hav'nt messed with it enough to know if I have a reserve or not.

Have had real bad experiences with XS650 vacuum taps and when I resurrected my eleven, I saw the octopus as potential trouble and set them aside.

Remembering to shut off the fuel is not a problem as my 80 is the newest bike I have. Well trained on turn off key, shut off gas.

[Jdwags]

non-octopus routing of fuel lines

My mongrel came without an octopus,

what the po had done (one thing he apparently did right) was to take and run a line from each port of the petcock, and t them together and run on to the carb.... did it for both sides,


that way the petcock works for every position, and i do Have a reserve..

Seems to work great, cept the rembering to shut it off thingy

[nashville_bill]

My bike also came without the octopus, but I thought I needed the vacuum shutoff feature. I have had no problems with the one on my XS650 for 20+ years now. The first time I put gas in the XS11 I had gas everywhere and I found gas in the oil when I changed it. I put new needles and seats in the carbs and fixed the problem with flooding until the next time I put gas in. I found some trash(probably rust) in the carbs and had to clean them again. I then put filters on and now it seems to be starving for gas. I have a real ball of worms looking thing with a lot of up and down loops. I will try to streamline it this weekend.

[Mike Hart]

Bill there is more than one way filters can make your bike starve for gas. Here's a good tip with diagrams that might help.

[nashville_bill]

Mike,

Thanks for the link! I had seen this a while back and had attempted to use the idea when I installed the filters but I hadn't printed the info and my memory isn't as good as it should be. I can now see that I didn't follow the instructions. In this link, is there only one fuel line comming from the petcocks?

[Mike Hart]

hmmm, good question Bill ~!

the Prime tap is conveniently ignored in that diagram!

Apparently he doesn not have an Octopus bike either...

You could Tee the two taps before they go to the filter?

When you work this out, post how you did it!

[skids]

If the advance plate is looking out of balance, I would check and lube the centrifugal advance unit behind it. I think someone mentioned this in an earlier post. If the weight(s) are somehow sticking, it would be out of dynamic balance. That thing tends to be neglected.

[nashville_bill]

Mike,

I did a great job re-designing the fuel hoses and I was going to take a picture and send it to you, but it wouldn't run right. It was starving for fuel and, after a little troubleshooting, found out that the gas was getting to the filter and out of the filter but it wouldn't go over the upper loop before the carbs.

SO I TOOK ALL OF THE OCTOPUS OUT AND RAN IT STRAIGHT FROM THE PETCOCK TO THE FILTER TO THE CARBS!!!!

Runs great now. I will try to get it together with the air filter on this weekend so I can ride it.

[Mike Hart]

Runs great now? XSellent!

hmm I thought from your earlier post that you were octopus-less. That tip assumed no octopus. Well, handsome is as handsome does so your bike must look great

What did you do with the Prime tap? Plug it, or tee it?

[nashville_bill]

I was using the prime tap. I connected the other two together using a piece of hose.

I have been thinking about it and I think I will try using the octopus again with the filters running horosontally just above the carb throats, like they were last night. I have plenty of hose and it shouldn't take that much more time. I really want a vacuum shut off since I park the bike in my basement near my gas water heater. Would hate to blow up some night.

[jkgrubbs]

I finally had time to play with it. I shimmed the needle seats and it seem sto have done the trick. The boots were in good shape, and the octopus is a workin' now. Much thanks for the inputs

jkgrubbs