#2 cyl killing me -1980 xs1100special

[wylie coyote]

Running too fat and fouling the plug. Replaced coils and wires- they check good now. Pulled the carbs and repaired diaphrams, checked float for hanging up- didn't appear to be. Carbs didn't appear to be dirty or anything. Repaired wires on coil pick up- advance okay. Octopus not leaking through the vacuum line into #2. Likely carbs, but >>>need something sorta specific to look at<<<. Headpipe colder on that cyl. Put a timing light on it, and the plug showed firing okay. I swapped plugs for that hole also. The only thing I haven't done is replace all the plugs again- they were new when this all started- but figured if the light showed firing, it should be okay. Plug shows fouling (and there's obviously a miss and drop in power) on this cyl only. Other cyl's okay. The bike has been sitting for about 9 months, I think it was happening when the PO unloaded it to the guy I got it from. Runs better when up on the rpms, like it is able to burn the extra fuel..... Thx.

[psycoreefer]

Did you do the work before or after the new plugs? If after try replacing the #2 plug with one that isn't fouled and see if it fouls again. Some times they don't clean up very well even if you've corrected the problem

Have you tried adjusting the idle mix screw on #2? Did you synch the carbs?

Have you done a compression test?


Look over everything in #2 carb carefully, compare with #3, is the needle the same, same size jets? maybe the PO broke the tip off the idle screw and its shorter then the rest.

[motoman]

If you haven't had the carb bank off and pulled the bowels yet........best start there and at least do the "tripple clean", check/set float levels...back on, re-sync, re-set idle mix, resync, re-check that all you've done is all good......no shortcuts allowed or get in a hurry.....you'll be banging you head with frustration, without following one step at a time.

[dbeardslee]

+1 on the float set. From what I've seen that seems to have the biggest impact on plugs sooting up - assuming the jets are right (or close) and the carbs are clean. Sometimes a leaky valve stem seal will crud them up pretty good too.

[XS1100 Newbie]

I think i would also do a compression check to make sure you don't have a problem there. The float level is critical as i found out on mine.

[yamtom]

regarding number 2

You may want to pull the number two bowl, and in the bottom of that bowl, is a jet, in a drilled hole, if you cant pass compressed air thru that jet and out of the hole at the bowl base in which the copper tube fits, you have a plugged up jet. I just had this, and it will kill the cylinder.

[yamtom]

what happened

Hi,

What did you find out happened to your number two cylinder anyways?

[wylie coyote]

It's in the works- I just now came in to post. Decided to go from scratch on things. Pulled it all down, did the cleaning, float adj, and checked it all out, make sure all orifices were clear and clean. Especially in the bowl like you suggested. Found all the float (needle) seat o-rings were likely shot- loose in the bore after I pulled the screw/plates off. So there was possibly leaking through on those. Found the idle screws all adjusted a bit out- the manual calls for 1-1/4 from seat, they were somewhat more than that. But on #3 carb, the idle screw was way too far out, and the slot on the head was ruined , so I couldn't turn it out. Had to drill it out w/out damaging anything. Got it out perfect w/ no damage to seat or threads. In fact, the slots on all of the screws were chewed up. Float settings were in there, only had to tweak one a tiny bit. I alsso ran a compression check, and it came in even on all cyls. The jetting turned out to be stock, even tho the PO had told me otherwise (He had a 4 into 2 on it) . So.... long as I'm this far, I'm thinking about going to the pod air cleaners and rejet the whole thing anyway. Still haven't found anything specific to #2 tho, unless it was the o ring, and maybe something got cleared out of an orifice and I didn't realize it. Going to order the jets and stuff tomorrow probably, then continue on. Thanks ahead of time to everyone on here who is helping me out on this. Much appreciated.
Will keep you posted on progress.

[psycoreefer]

Just MHO but I'd get it running right the way it is before you start changing things - like the pods. You'll get to a point where you've changed stuff and can't get it to run, but because it didn't run before there are too many variables to try and consider. I know its a little more work but might save you a lot of work down the line a bit.

[DGXSER]

Yep, I'd get it running on the 4-2 with the airbox. Stock jetting should wokr for that setup pretty well.

As to the mix screws, anything under four turns out is not bad. When I first got my bike all were three turns out. I run them about 2-1/2 now. My project bike they are all about 1-1/2 to 2 turns out. Both run pretty good.

IT is amazing how small a piece of junk can effect the float valves. I was using automotive fuel line on my bike for a while. And I had nothing but problems with float valves sticking open. I finally figured out that when I shoved the fuel line onto the barb of the carb inlet T, it would grate off pieces of that soft inside rubber lining in the fuel line and they were getting to my float valves and sticking them open. I switched to lawn mower fuel line by B&S. Never another issue with fuel lines since.

[DiverRay]

Leaking "O" rings on the float valves are probably the problem. I've been chasing a problem with my "new" daily ride for months, and replacing the needles seems to have fixed the running rich problem. The newer style carbs with the "O" ring seems to have their own problems, as most people seem to overlook just how critical the "O" rings are.

[wylie coyote]

Good point on the 'get it dialed in before going to the pods'. I'll wait until it's right before I do that one. I'll fire it up OEM soon as I can get another idle screw- today I hope.
Yeah- all of those o rings seemed too loose to me...they were more of an (easy) slip fit-you could pretty much remove them with just your fingers, which I think would leak at least some anyway. Interesting to see how much it matters on the fit. Who knows what else is going to show up as a PO "fix". Thx again, guys.

[wylie coyote]

Just checked on the idle screws. Dead in the water till nextr week sometime.

[wylie coyote]

One question- just in case. After I took the carbs apart and cleaned the orifices and blew it all out, I found a pin on the floor by the bench where I was working- it measures .062'' diameter, and .900 long:confused. Resembles a float pin, but smaller and without the head. Just wondering if this came out of something I missed, or I was a lousy housekeeper from some other project. I was careful when I did the carbs, and don't see it on the schematics anywhere, and don't really think it goes anywhere in there. Any comments? I need to get some sleep and get over this one way or the other.

[xj11john]

mysterious pin

Sounds like an old float pin from a lawnmower or other project, I would'nt worry about it since the only pins in our carbs are the float pins, and it would seem hard not to put one back in while doing the carbs. Get some sleep.
Good luck with finding the problem.