Missing question!!

[hanger10]

Hi all, mabuhay from the Philippines. Ok, got a question. I bought an 80 xs1100 spedial, SG. The carbs just got rebuilt, and I still have the same problem, and I will try and explain. When I reach cruising speed, whatever that speed may be, and I lean off (let off the gas) slightly, and the give it just a bit more gas to maintain speed, it starts missing on 2 cylinders. I have to let off the gas completely, then start again, it backfires, then runs fine until i lean it again, and then give it just a bit of gas. We have been persuing thisfor 3 months, anyone have any idea what is wrong??? Oh, and it makes no difference about the rpms, it does the same at any rpm. HELP!!!!

[blue giant]

Hey Hanger10,

Have you checked or tested the pickup coil wires yet? That is my first thought since you have already overhauled the carbs. Any exhaust mods to the bike? Does it have the stock jetting?

[xsilerating]

Hey Hanger10,

Have you checked or tested the pickup coil wires yet? That is my first thought since you have already overhauled the carbs. Any exhaust mods to the bike? Does it have the stock jetting?

Yea, I agree with blue giant. Check your primary coils and all of the wiring in and around the primary housing. Also, check and ensure that all ground connections are clean, tight and, there are no broken wires.

[DGXSER]

Yep, I think these guys hit it on the head with pickup coil wires. When you let off and then roll back on, your changing the vacuum which change your timing advance and will rotate that assembly moving those wires which often stretch and break on the 78-80 models anyway, less on the later years due to no mehcanical advance. That would make the break show up, and each pickup works for two cylinders IIRC. Lots of threads on here from those with more knowledge than me on how to fix it.

[dbeardslee]

When is the last time your carbs were synched? After they were rebuilt?

[trbig]

Check your primary coils and all of the wiring in and around the primary housing

Have you checked or tested the pickup coil wires yet?

Two different things. Primary coils are under your tank, but the pickup coils under the left sidecover of the motor is where the problem is probably going to be. That's the first thing I would check anyway.


Tod

P.S. You can figure out which cylinders it's missing on by spritzing the header pipes with water and finding the hot/colder ones. MOST of the time, if the miss is together.. 1&2 or 3&4, it's fuel related. If it is 1&4 or 2&3 together.. it's usually electrical.

[hanger10]

The carbs were synched today, as soon as he finished the rebuild. I will show him these messages, and have him check the coil, and all around it. I just pray that we can get this thing fixed!!! It runs like a gem, except for this damn miss!!! Thank you all so much for the responses!! Mabuhay from Liloan, Cebu, Philippines.

Randy

[blue giant]

The carbs were synched today, as soon as he finished the rebuild. I will show him these messages, and have him check the coil, and all around it. I just pray that we can get this thing fixed!!! It runs like a gem, except for this damn miss!!! Thank you all so much for the responses!! Mabuhay from Liloan, Cebu, Philippines.

Randy

It's guaranteed to be something simple like pick up coil wires or a poor/corroded connection. You're very close to having it run perfect!

Paul

[The Lorax]

Bienvenido a xs11.com, may as well throw my vote in....p/u coil wires...like everyone else (mostly) said. have a nice day and ride safe

[fredintoon]

There's coils and there's coils

Hi Hanger 10,
to be clear about this, the XS11 has two coils that feed sparks to the engine,
these coils are located under the gas tank. There are also two pickup coils, or trigger coils, under the circular hatch on the left side of the engine. These coils trigger the spark coils in place of the old-fashioned breaker points. It's these smaller coils, or rather, the wires that lead to them, that are the most likely cause of your problem. As the vacuum & mechanical advance systems move these coils back and forth the wires are continuously flexing and sometimes the conductors break inside the plastic insulation. The wire looks perfect as only the inside is broken. Thing is, normal bike wire is not the best replacement as there's too few too fat wires in the conductor. You need a larger number of finer wires in the conductor to make it sufficiently flexible. What I used when my XS11SG had that problem is the very flexible wires from an old multimeter.