only 1/2 the engine running

[Wbowen]

Another Newbiee question;

To make a long story short I own an 81 xs 1100, I puchased the bike about 2 week ago. I had the fealing that the bike was not as powerfull as it was when i test drove it. I replaced the plugs 2( (1&2)were clean and 2(3&4) were dirty)and took if for a long ride (50 miles). When I got back to the house I squirted the head pipes with water and 2 sizzled and 2 did not.

I believe that cylinders 3 and 4 are not firing. I also noticed that there is some liquid leaking out of the header pipe for cylinder 4, I do no tknow if it is gas or oil.

What test can I do to narrow to help figure out the exact issue.

Thanks

[81XS1100-2006]

I had a similar situation when I bought mine in Feb.

You might need a new coil, or set of coils. Cyl. 1 & 4 / 2 & 3 per coil. there are tips on checking the coils in the Tech Tips.

Or (and this is what solved all my problems) a rebuild of the carbs... float needles and seats might solve the fluid comming out of the pipes.

[underdog57]

Do you get spark ??
And a compression check would be good in my opinion ...
Also can squirt gas in the 3 and 4 carbs to see if you get them too run . that will tell you if it will run with carb work at least...
be carefull , extinguisher is good to have around..
let us know what youfind
Bob

[Ken Talbot]

Cylinders #3 and 4 dead would indicate a fuel supply problem as they are both fed from one petcock. Look for a kinked hose under the tank.

[HobbyMan]

It sounds like a fuel problem. Before checking coils or even taking the tank off, take out the carb drain plugs to see if there is fuel. If the carb bowls are dry, it is probably a simple fix. Check for kinked lines. Make sure there is gas in that side of the tank if it is low

[newmaac]

Well, you've already had several good suggestions to look at. My first thought when I read your post was to look at the pick-up coil wires.
Check to see if you are getting spark at the plug wires, if not, before you even check the coils, see the tech tip about checking the pick-up coils.
The wires are Notoriously bad on these bikes and if they have not already been repaired, they probably will need to be soon.

just my .02

Let us know what you find.

[Wbowen]

Thanks for all of the input,

I will let everyone know what I find out.


Thanks

[DELL82]

Hot side vs Cold side

I am having a similar problem. Finally got the bike up and running, sort of. 3&4 get so hot they bubbled the exhaust paint job but the 1&2 side looked good. Checked the firing and have good spark on all cylinders. Checked the bowls for fuel and all is there. Octopus is working okay, no leaking. Have a temp bottle of fuel above the bike hanging from the ceiling on bunji cords. Removed the tank and connected the fuel lines from the petcock valves output to the temp fuel. This all seams to work okay. Pulled 1&2 plugs and found black sut and wet, 3&4 were half black, half white. NEW 0.032" gapped plugs. WHAT NOW? Just received my GRIMLIN BELL so got to get bike running.
Dell82

[HobbyMan]

Just curious, how is your compression? If it is running "HoT", it is usually lean. If your carb intake boots are cracked badly, they will make it run lean because of the extra air being introduced into the mixture. This may not be the problem but it is something to think about.

[prometheus578]

"Hey Squirt... how ya doin'?"

I squirted the head pipes with water and 2 sizzled and 2 did not. (1&2)were clean and 2(3&4) were dirty)

Ok, bike is running on two cylinders.
Cyl's #1 and #4 run from one coil, #2 and #3 from the other. As the faulty cyls are #3 and #4, that would indicate fuel, not electrical, as Ken alluded to. The plugs being fouled, would indicate too much fuel, not a lack, thereof. (would also fall in line with the juice running from the header pipe) Pinched fuel line: the plugs would be white and bone dry(This Ken knows, just hadn't had his coffee yet.)
You, kind Sir, have a carb problem. I suggest the Atkin's Diet.
You just got the bike... it may have sat fer a spell, or the owner decided to rid himself of it 'cause it wasn't running right.

You now get to pull the carbs and become a true XS'ive.
#3 and #4 are fouling 'cause the float needle valves are not sealing and fuel is pouring in. That, and the floats are sticking down or are misadjusted. Easy fix. Replace all needles and readjust. Bench test the carbs before replacing them on the bike.
If you have fuel running from the pipes, then you also have fuel that ran down past the rings and it's time to change the oil, too.
Compression test is always good with a new bike, as that lets you know where things are internally.
Pick-up coils are ok, as the plugs do fire(They're fouling, right?)
Sure, faulty spark can foul plugs, too, but that wouldn't explain the fuel running from the pipes.
DELL82... get with Wbowen and pull your carbs together. You both are similarly afflicted.
Exhaust pipe paint will bubble, depending on what they were painted with. I use the stuff that I paint my wood stove with, or try a high heat paint for barbeque grills.

If your carb intake boots are cracked badly

Cracks are usually cosmetic, as the boots are double walled, but yes, I've seen them suck air before.

[DELL82]

Thanks 'Bones' McCoy. My boots seam to be Okay, had some superficial cracks but I painted with RTV and looks good. I have another set of carbs that I will take apart. My Xj1100J Maxim has Makuni carbs but a tech note on jetting says that they should be BS34 Hitachi! Does this matter, has the carbs been switched? Will be using lacquer thinner to soften the varnish on the spart carbs as the are froze up with black varnish. Ps Used Duplicolor 1200 Degree paint but have not seasoned it yet. I was hoping that short runs(10MIN) would get the seasoning done until I run into this problem.
Dell82

[DELL82]

'Bones' McCoy, I ran a compression test and results are #1 87PSI, #2 85PSI, #3 85PSI and #4 83PSI. Are these Okay Pressures? Cannot find info on proper pressures. Thanks Dell82

[underdog57]

compression check

Hi Dell .
After you do the compression "dry" Put a teaspoon or so motor oil in the cylinders and give another compression check ...

If it raises you have worn rings ....

I find a compression check best with a warm engine , cold and they are all over the place ....

Yours sounds low would rather see closer to 150psi, but very even....

Bob

[Ken Talbot]

Re: "Hey Squirt... how ya doin'?"

Originally posted by prometheus578
Pinched fuel line: the plugs would be white and bone dry(This Ken knows, just hadn't had his coffee yet.)

Prom's probably right on this, but I'm still a bit suspicious of two carbs having the same internal problem at once and causing similarly dirty plugs. I'm thinking the fule supply is pinched off so those two aren't firing. At the same time, the pistons keep going up and down, cleaning a bit of oil off the cylinder walls each time. That oil collects on the feebly sparking plugs and makes them wet and nasty.

Then again, maybe now I've had too much coffee..

[DELL82]

Hey Guys, After reading the forum on a search for compression found out that the throttle should be open. I did not do that on the first readings. Following the reccomended procedure I put oil in each cylinder then opened the throttle and got the following pressures: #1&2=123PSI, #3&4=102PSI.
Bike has been setup since 93', I have been over everything, I thought. Original owner tried to sync carbbs in a garage without fan and reported 3&4 over heated so he shut it down and waited to cool. Tried to crank and it did, but not start. He then let it set thinking he had ruined the bike. I bought it from him 14 years later.
WHAT DO YOU THINK? Should I wait until I can ride it to clear out carbon on the valves before getting worried?
Dell82