xs1100 special fouled plugs

[dewibp]

Bike Bandit did not show the needle valves ( are attached to the pistons). I want to get them new too so everything is hopefully back to square one. Did I just miss them on Bike Bandit site?

[TopCatGr58]

Hey Dew,

The "SLIDE NEEDLES" are discontinued. But unless they are bent, there really isn't any reason to change or replace them. Just ensure that they are well cleaned off varnish/gum!

OF course if we had 650 twins, then we could still get them thru MikesXS, but they are the wrong type/size for our carbs!
T.C.

[dewibp]

Okay here is the latest update. Pulled carbs apart again and noticed a couple things different. The two inside carbs 2-3 have 10 small holes in the sides of the needle jets (slide needle fits into them) and the two outside carbs have 12 holes. I have read that on some cycles they have different jetting on the inside two carb to run them richer (cooler) to compensate for the heat. Is this suppose to be this way on a 79 xs11 special? I did notice, after a short ride, that #2 plug is a little brown and the other three are pitch black (sooted). I also did another little test. I slid the slide needle into the old jets that were in the carbs when I took them apart and put a mark (with pencil) at the point they bottomed out. I then did the same with the new K&L and found the slide needle did not go in as far by almost, but not quite, 1/16 inch. Obviously there is a problem and I suspect that it is with the K&L and just once again confirms what poor quality contol program they have, but by not going in as far the motorcycle should've run leaner helping reduce or eliminate the fouling problem I am having???!!! Also, I am considering putting in the original jets (larger holes) to see what that does or should I also lower the slide needles too? Any thoughts on the issue with 10 to 12 holes, the smaller size jets and slide needle position would be appreciated.

[TopCatGr58]

Hey Dew,

Your emulsions nozzles are in the correct locations, the holes are for air, so more holes on the outside for leaner, less holes on the inside for richer=cooler running for the inner pair that normally run a bit hotter due to less air cooling effect.

Set your needles back to center position. You already have the floats set to 27mm, very lean, and with the proper OEM jets, you should then get better color, lot less black soot! DOUBLE CHECK your float heights, cause #2 being brown vs. the other 3 being black could indicate that things aren't quite evenly set !?

Seeing how far the needle will go into the main jet hole is irrelevant, cause the slide needle NEVER gets to the main jet when it's in the carb. The slide needle fits into the NOZZLE, the main jet is screwed into the OTHER END of the NOZZLE, and merely meters the fuel flow thru it. You would think that the older jets having a larger hole would be richer, but it's not just the size of the hole, but the taper going down into the hole, etc., how long/deep the material is where the hole is narrowest....like a piece of hose 1" vs. 3" long, more resistance with the longer hose, even though it's the same diameter!

I know this may involve having to remove the carbs later for further tuning, perhaps re-adjusting the floats, as well as the needles, but you want to change 1 thing at a time and see what it gets you!
T.C.

[dewibp]

To clarify one point. I have NOT changed the needle setting yet.

I need to think about your statement about the depth of the hole and the resistance, etc.....MIGHT not buy into this theory. I was just using the needles to determine hole size in jets to see if there was a difference.

I will put the old jets back in and see what happens. Thanks!

[TopCatGr58]

Sorry about that DEW,

Just please put the PILOT jets back in as well, not just the mains! The pilot jets are most likely the main culprit to your excessively rich condition.
T.C.

[dewibp]

Yes I was thinking along your lines with the pilot jets being the problem and had all ready installed them with the resulting "Same Problem"!

I am reading "Blaines xs11 Carb FAQ" and he talks about the main air jet being pressed in and must be cleaned very well. It is suppose to bleed air into the needle jet to emulsify the fuel and dilute it for more precise metering by the jet needle. Where is this located so I can double check the cleanleness?

Again, thanks

[Shuriken]

Many things can cause the rich condition. Plug reading is a good first step.

What I would do is go find a hill and ride your bike up it at wide open throttle in maybe 2n'd gear. Be careful - that's fast. As soon as the throttle is open full, turn off the engine, pull in clutch, and coast to a stop. Remove your plugs and examine color. You want the good light-tan color. If plugs are still dark, main jet is too large. If plugs are too light, mains are too lean.

After you know you have the right main jet size you can repeat the above test at half-throttle and examine plug color.

The whole idea is to tune each carb circuit (idle, mid, full) properly. You need to do one thing at a time, however.

You could see what jets are in the carbs. I'd always start with OEM stock parts to make sure and set everything to stock. Then I'd mess from there, but not until making sure everything was stock and/or that the main jets were right.

If full and mid throttle are fine (by plug color), then if it were me, I'd set float height to stock, pilot jets to stock, and clean all of the pilot orifices in the carbs. I'd make sure the vacuum diaphrams don't have holes in them. I'd check pickup coil wires, clean the air filter, gap the plugs. I'd check to make sure floats aren't stuck or leaking. I'd see if I could check actual float level with plastic tubing. And of course, I'd get the idle mix set right with either color tune or by listening to combustion, and finally, I'd synch the carbs. Synch is huge.

Ben

[TopCatGr58]

Hey Dew,

The air jets are in the edge of the inlet bell. Because they just let in air, it's a bit more rare for them to get plugged, but the passages can get that way! Take some carb spray cleaner and squirt it in thru the opening, and you should be able to see/hear where it comes out at inside the carb. The air jets in the earlier model carbs can be removed/unscrewed, but I think the later models are presized and pressed in!

Like Ben said, make sure the floats are moving freely on their pins, not getting stuck/binding!

Oh, oh, just thought of something! After you replaced the pilot jets, did you put the pilot jet plugs/caps back on over the pilot jet holes? Either rubber caps, or even metal screw on go over them. IF you don't have the caps, then that's where you're getting too much fuel, cause the pilots are supposed to meter via a hole in the side of the MAIN JET Tower, that's why the mains are so much larger. However, if the caps are not there, then it's getting fuel directly from the bowl AND from the mains!!!!
See picture below:

T.C.

[dewibp]

I am a little dense this a.m. about the air passage that you are refering to. Are you saying, if you look into the end, air filter end of carb you can see it from this end?

I have the metal screws in place over the pilot jets as shown in your photo.

[skids]

Thats right, the main air jet is pressed in and is very small. It is in the perimeter of the inlet bell. In my experiences, they do get restricted and must be sprayed with the straw from the cleaner.

Originally posted by dewibp
Yes I was thinking along your lines with the pilot jets being the problem and had all ready installed them with the resulting "Same Problem"!

I am reading "Blaines xs11 Carb FAQ" and he talks about the main air jet being pressed in and must be cleaned very well. It is suppose to bleed air into the needle jet to emulsify the fuel and dilute it for more precise metering by the jet needle. Where is this located so I can double check the cleanleness?

Again, thanks

[skids]

If you are going to remove the bank-'O-carbs, you might want to read this for quick cleaning. You can get a pretty good idea that something is clogged if cleaner doesn't run through freely:

http://home.earthlink.net/~sidskids/carbs/spraycarb.htm

[dewibp]

Well I put all the original jets back in, left the floats at 27 m.m., left the needles in the center position and now it cuts out at about 4-5,000 r.p.m. kinda feels like its running out of gas. PLUS I still have the plug fouling issue! Any ideas left to try?

[TopCatGr58]

Hey there DEW,

Back to basics, and I just remembered about the bowl vent tubes!! The second set of "T"s higher up on the carb bodies just above the fuel "T"s! Check to make sure they are OPEN and flowing freely!!! You may have to pull/separate the outer carbs from the bank, but maybe not, just remove the bowls, and spray some cleaner into those "T"s and make sure that it comes out thru BOTH carbs!!!
Next, check your stock air box, and those hoses from the vent "T"s, make sure the hoses are NOT CLOGGED, and make sure that where they fit onto the airbox, that those nipples are not clogged, they need to be able to vent to air! IF they are clogged, you get these same kind of symptoms! Sorry I didn't think to tell you about this before!?
Aside from this, checking the pickup coil wires is about all I have left in my suggestion box!?
T.C.

[Czekus21]

Hey dew, I never thought of checking the breather "T's". The weekend after I get back from Sturgis, If It's still not running, I'll pull the carbs off of MIYAMI and head down your way, Or I'll head down your way and then we'll swap carbs. Either way. we'll pull the carbs from both bikes and compare the two. The problem has got to be a simple problem staring us in the face. By doing what we did to them that HOT sat. It should've ran great. I guess we missed something. I'll be pretty busy between now and the weekend of the 12th/13th. Then free till the 30th when I go on call.