FINALLY. got the old 78 XS11 to run great!

[Diskman01]

After synching and re-synching the carbs, adjusting the float levels again and fiddling the leaking vacuum port plugs on the boots, the old girl is running GREAT. Managed to put 110 smooth miles around the city last night. Usually I give up after 10 minutes because the backfiring and crankyness is too much to deal with. Not anymore!

My spark plugs still turn extremely black at 30-40MPH around town. No idea why. I just pull the clutch and clear it out with a quick blip avery few minutes. Interstate speeds are awesome and plenty of "GO" left on the throttle.

Tried turning the idle mix screws in 1/4 turn to lean her out but it starts popping on decel and general "lean" at idle with severe throttle "sag" from lights. Guess I'm stuck with sooty plugs at low speeds. Idles very smooth at 900 to 1K RPM though. I'm double checking the tach at lights in traffic to make sure it's still running. It's that smooth and quiet now.

Acceleration is very smooth. Getting a little "extra-twisty" on the throttle around town is pucker inducing now.

Very fun to drive now.

[DGXSER]

Awesome!! Glad your enjoying the beast!!

As to your sooty plugs, what float height did you settle on? 30-40 MPH with stock FD and 5th gear is about the 3k range, which is where the main jets just start to come into play.

[skids]

The 3000 rpm is the top of the "transition" range from the pilot to the mains needle. If you aren't having troubles with actual fouling of the plugs, I wouldn't worry about that much.

[TopCatGr58]

Hey there,

Well congrats sort of! I found/read your other thread you started regarding the carb problem. BikerPhil talked about the PILOT jets possibly being the wrong style, and you said the PO had done work on the bike...new coils/wires, so "we/you" can't be sure that he didn't replace the jets



There's a diagram(above) that I borrow/post from MikesXS site that shows the difference between the BS style and VM style pilot jets. Many folks have reported that they had gotten the VM style jets in K&L brand carb kits and had the same type of running symptoms, way too rich in the low speed circuit, black sooty plugs, etc.. Skids, I think it's just a matter of time before he DOES end up fouling his plugs running it this way!

I would suggest pulling the carbs and the Pilot jets and closely inspecting their design to see if they don't look like the VM style with the tapered/metering orifice near the threads instead of near the tip like the BS style(the right kind). Also may be a stupid question, but just want to make sure that you do have the pilot jet towers capped??

T.C.

[Diskman01]

Hey there,

Well congrats sort of! I found/read your other thread you started regarding the carb problem. BikerPhil talked about the PILOT jets possibly being the wrong style, and you said the PO had done work on the bike...new coils/wires, so "we/you" can't be sure that he didn't replace the jets



There's a diagram(above) that I borrow/post from MikesXS site that shows the difference between the BS style and VM style pilot jets. Many folks have reported that they had gotten the VM style jets in K&L brand carb kits and had the same type of running symptoms, way too rich in the low speed circuit, black sooty plugs, etc.. Skids, I think it's just a matter of time before he DOES end up fouling his plugs running it this way!

I would suggest pulling the carbs and the Pilot jets and closely inspecting their design to see if they don't look like the VM style with the tapered/metering orifice near the threads instead of near the tip like the BS style(the right kind). Also may be a stupid question, but just want to make sure that you do have the pilot jet towers capped??

T.C.

95% positive they are the BS jets. I will double check next time I feel like messing with it. Ya, the screws/washers are covering the low speed jet tubes in the carbys.

Can possibly be the coils. PO replaced a set of green coils with some original XS coils. I asked him about donating the green coils to me a bit ago, but he didn't seem to interested. I was unaware of the green coil upgrade when I purchased the bike so I told him to keep em... Doh... I think he did some googling and found out they are worth a few $$. crap.

Will check into the low speed jets though. Just to make sure.