xs1100 special fouled plugs

[dewibp]

My "creation" is now driveable but now I am experiencing foulded plugs. After a short trip (5 miles or less) it starts missing on the left side (#1-#2) cylinders. I pull out the plugs and both are black. So here goes the question between oil fouled and soot fouled from too rich a mixture. How do you tell the difference by looking or touching the fouled plugs? When I wipe them off on a shop rag they feel kinda sooty and kinda oily???!!! I put them back in and in 5 miles it starts missing on this side, I clean them runs great for a few miles and the problem crops up again. I bought the motorcycle used and only the good Lord knows how long it set. The head gasket was leaking on it so I had a shop replace. They said there was some pitting in these cylinders so they ran a hone thru them to clean them up a little before reinstalling the block and head. They checked compression and three cylinders were around 150# and #1 cylinder was down around 125#. I've tried as hot a plug as I can get with no luck. Any thoughts or directions to take? So first big question is reading the plugs is it oil or soot?

[skids]

Well, I think that once it fouls bad enough to quit firing, it will start colllecting fuel on it. Fluffy dry black is carbon fouling and as you mentioned, oil fouling will look oily. If it is fuel fouling at mid to lower range rpms and the air cleaner is clean, you can check the float heights, adjust the pilot screws in a little and make sure that the fuel valves in the carbs are not leaking passed the orings or the needle seats. If it is oil fouled, you can try using a hotter plug.

[dewibp]

To determine if it is soot or oil I never use the choke to start it. It starts up quickly with no choke and runs pretty smooth for being cold (summer). I still can't get it through my thick head how to tell soot from oil. When I rub it on my hand it is somewhere between sooty and oily! Can't explain it to you very well. On top of this #4 and #3 plugs look pretty good and hit all the time. I even bought another CDI unit and coils (both used) put them on and the same thing happened. I wanted to try and rule out ignition issues. When I take it for a 5 minute ride I never take it over 4-5000 rpm's. I will take your advice and turn in the pilot screws (for low speed) how about 1/4 turn IN to see what that does? Also if I took a close up picture of the plugs and posted to this site do you think you could tell if it is carb's or rings/valve guides etc. ?

[TopCatGr58]

Hey DEW,

That bike shop may have done you a disservice in several ways. First, if they had the head off, they should have recommended replacing the valve oil seals!

Secondly, they did a honing, but didn't put in NEW OEM sized rings, so they increased the diameter of the cylinders, and didn't use new rings, so the older rings may not seat and seal effectively against the cylinder walls, so suspecting some oil slipping by the oil rings is a possibility, as well as the valves!!

But more information about what you've done/or had done to it is needed, like carb work? Improper jets, both sizes and brands can have drastic effects. What kind of airfilters, OEM box or Indys? Some Indy types are restrictive around the intake bell inducing severe choking/richening the mixtures!
T.C.

[sermn8ter]

Not sure if it fits here or not

My bike was fouling the #2 plug bad. I had really bad performance issues. I changed plugs and it would run good for a little while, not even a whole day, and it would be back to fouled again. Since I just bought it and didn't have my manual yet, I took it to a garage, (great guy by the way) and had it looked at. I was suspecting carbs, and part of it was the #2 carb had something stuck inside of it, but the biggest part I think was my octupus. I know that probably sounds crazy, but apparently the PO messed with it and somehow poked a hole in it, and it was leaking gas all over the place, and obviously getting too much some places and not enough in others, or at least thats my take on it. New octupus, carb cleaning, syncing, and rejetting and I am flying like a new machine.

[LoserShoes]

Pretty sure it's a fuel problem, if you were using enough oil to foul a plug that quick, you would be putting out such a smoke screen there would be no doubt whatsoever.

Check to see if the enricher is connected on that side.

Steve

[dewibp]

To answer a few of Topcat's questions-
Carb's were gone threw (cleaned) - New parts (the ones everyone bitches about) K&L brand??
Has stock OEM air filter box
New air filter

PS had to wait till I got to work to answer you.

[TopCatGr58]

Hey Dew,

Well, hopefully you kept the old jets, pilots especially. Clean them(pilots) and put them back in, and you'll probably see a big improvement in performance and non-fouling with the OEM pilot jets. If you don't have the old ones, you can get replacements from several sources, Mike'sXS, motorcyclecarbs.com, etc.! Those K&L are crap!
T.C.

[Czekus21]

We can see if it is the carbs. I can pull the carbs off of MIYAMI and we can try em on your bike.

[dewibp]

Czekus21 I just sent you a PM with my cell phone number. Amazingly I was smart enough to save the old carb parts! If your game for Saturday, I sure am. I will buy some new plugs and if you could also throw in a compression tester (if you don't have one) I would buy one. It would be easily worth a couple beers and a good meal when we are done. Call me tonight.

[dewibp]

79 xs11 special

Should my 79 xs11 special have brass or plastic floats in the carb's? Mine now have brass and was wondering if either will work but require different float heights? (brass verses plastic) I (and a pretty good helper but cant be named) set my brass ones at 25 m.m. and I still have a plug fouling issue (carbon). I was just wondering if maybe it should have plastic floats and if so maybe they are set at a different setting that might lean it up. By the way today I am going to change them to 27 m.m.

[TopCatGr58]

Hey Dew,

Did you check each float to ensure that it really does float, and doesn't have any leaks, by putting it in almost boiling water, and submerging it and looking for bubbles which will indicate a pinhole or more!?!?

The Plastic floats on MikesXS are what you'll want, don't get the brass ones from Mike. Nobody has posted about any trouble measuring for them vs. the brass ones!? Of course if you replaced all 4, then you could tune easier by just getting them all even, and then raising or lowering as needed, but that's the more expensive technique.

BTW, the OEM floats are brass! T.C.

[dewibp]

Just finished test riding after setting floats to 27 m.m. from 25 m.m. to see if this would help the fouling issue with no luck. I am still fouling #1,#3&#4. #2 plug looks pretty good with a light tan color on the insulator. Back in May when I first bought the bike I didn't know about this site and bought K&L kits and installed. Although I bought it as a basket case and don't know the history of the bike I do know that it has not run with out fouling plugs since I put the new K&L kits in the carbs. I am not so certain that I am going to get new kits from another supplier and start over again. Who would you guys recommend?

Also what jet sizes would you order?
The bike has the stock air box and stock (original) two into one exhaust.

[TopCatGr58]

Hey Dew,

Just clean and put the OLD jets back in!!!! You'll be amazed at how well it will run. IF you didn't keep your old jets, then you can get replacements from MikesXS, just don't tell them it's for an XS11!!!!!! They have a $35.00 minimum value order though!
BikeBandit also has them, see below.
IIRC, the stock sizes were 42.5Pilot, and 137.5 Mains!

Here's the info for Pilot jets, either 42.5 or 45.0

#42.5 Pilot Jet - BS30/96 Type - Fits: XS1/XS1b/XS2/TX650/TX650A (1970-75)
BS 38 Mikuni CV carbs, XS650G/SG/H/SH/SJ/SK/SL (1980-84) BS34 Mikuni
CV carbs. Sold in 2's

Part #48-0606 $6.00US /Pk./2

*******************************
Pilot Jet - BS30/96 Type
#45 Pilot Jet - BS30/96 Type - Fits: XS1/XS1b/XS2/TX650/TX650A (1970-75)
BS 38 Mikuni CV carbs, XS650G/SG/H/SH/SJ/SK/SL (1980-84) BS34 Mikuni
CV carbs. Sold in 2's

Part #48-0607 $6.00US /Pk./2
*********************************
FOR THE MAINS
Main Jet - Large Round Type
#137.5 Main Jet - Large Round Type - N100/604 Mikuni type - Fits:1980-84 Stock
XS650 Mikuni 34mm. CV carbs and aftermarket Mikuni TM 36-68 Flatslide carbs.
Sold in 2's.

Part #48-0120 $6.00US /Pk./2

*********************************
Main Jet - Large Round Type
#140 Main Jet - Large Round Type - N100/604 Mikuni type - Fits:1980-84 Stock
XS650 Mikuni 34mm. CV carbs and aftermarket Mikuni TM 36-68 Flatslide carbs.
Sold in 2's.

Part #48-0121 $6.00US /Pk./2

OR From BIKE BANDIT: I think $6.00 S&H
Just pick style, then pick size during ordering process!

Mikuni Pilot Jets (KBS 30/96)

Price: $8.99 Our Price Package of 4

MSRP: $9.99 Manufacturer: Mikuni
********************************
Genuine Mikuni Large Round-Type Main Jets (KN100-604)

Price: $9.00 Our Price(Package of 4)

MSRP: $10.00 Manufacturer: Mikuni

[Winterhawk]

Clean and put your old pilot jets back in. Some of K+L's kits had pilot jets that has to big of a hole in them. I always try and use OEM if I can on the pilot jets. Hold your new ones up to the light and compare them to the OEM jets.