New Member, New Bike

[Rudy]

Picked this 1978 up the other day for $700 with little knowledge of what an XS1100 was. Well, I have since rode the bike a few times and now I KNOW what it is. Its scary fast and by far the biggest bike I have ever owned, I like it already! I do have a few questions however.

I was running the bike at idle the other day and cylinder 1 and 2 were not getting hot at all. I have cleaned the carbs and I also have good spark. This led me to compression. So, #1 has 90 #2 has barely 100 #3 is 100 and #4 is 120. This seems pretty low so, I put a little oil in cylinder 1 and it shot to 180 along with cylinder 2. After this I ran the engine for a while, 1 and 2 were smoking like crazy and obviously firing now. So now for the questions.
1. What are the consequences of running it in this condition? I'm thinking rings eventually. What are your recommendations?.It seems to run fine but blowing some smoke out the exhaust of 1 and 2.
2. I also have a some tinking gurgaling noise coming from the left side of the crankcase by the crank. like almost if a screw was moving around in there.on the left side that has me curious.
3. is this custom paint Ive been looking around and can't find another one this color.
4. is this a gauge cluster from a 78? how about headlight and turn signals?
Hope you enjoy the pic.
Oh yeah the PO put drag bars and new grips on it. I think it gives it a good look.
Thanks for the help!

[GARTHXS]

nice one

dang rudy that bike looks awsome dig the paint and it looks like it was taken care of

[latexeses]

Welcome to the fold Rudy,

The color is not original. Matches my bass Boat. Original color was Macho Maroon. Allmost typed moron.

The gage cluster looks correct but the headlight and blinkers are from a later Special model.

That is an aftermarket seat as well. Looks sharp!

The engine questions I will defer to those who have been inside one of these motors... There are plenty of experts here for that.

What do the spark plugs look like? That can tell quite a bit about what is going on inside the motor.

When you get it running up to snuff you will know what quick is.

Rodger

[bikerphil]

I'd run it a bit more and the stuck ring(s) should loosen up and be fine hopefully. That's not a stock color but it sure looks good. Change all of your fluids soon. These motors can produce some rattling sounds that are normal, but I'd give a look under that left ignition cover just in case. Congratulations on your new acquisition. BTW, the headlight and front signals have been changed, it should have a square ones, but the guages are correct.

[latexeses]

Hey rudy,
Is that a special lurking in the corner of that first picture?

[Ken Talbot]

Make sure you check the compression with the throttle pulled wide open, or you will get low readings. I think your compression numbers look even enough to not worry about having to go inside.

Cylinders #1 and #2 going out at once point towards a fuel supply problem, as they are both fed from one petcock. Look for a kinked fuel line, or a cracked vacuum line on the line that controls the petcock that 1nd 2 are fed from.

Ride it a bit, get to know it a bit better before you worry about any major engine work, etc.

Sweet deal at $700!

[tarzan]

Wow ,smoking deal.Nice looking bike.
The seat looks like its been carved out where the rider sits.Hows it feel?

[petejw]

Welcome to the site,
the bike looks real good, nice colour.
Id also check the valve clearances,
has the bike sat for a while?

[Rudy]

Thanks for the help. I have not checked the valve clearance yet but will try to do so tonight. I believe the petcocks are okay. I switched the hoses around to see if one was bad and the bike reacted the same. This does not rule out the 1 and 2 carb though.

in the corner of the picture is my roommates honda cm 400.

If the petcock is set to prime is gas suppose to backup into the airbox?

[XJOK2PLAY]

Welcome, Rudy! You really got a great deal on that one for $700!
Good score!

Yes... don't put your petcock in that position.
If you have fuel now in your airbox, it might be a good idea to double check your oil... place on the center stand first, check the level in the sight glass... if over-full, you may have gas in the crankcase...
It has also been suggested as a tech tip... one can take a small stick, take the oil fill cap off, put it in there, remove it, ( get away from the bike,) and try to light it... if it flames up, gas is present, and an oil change is called for!
You can also smell and tell if gas is present.

It might be a good idea to remove the side cover and check on that noise... a screw may be bouncing around there...

These old 11's engines are kinda noisy by nature as far as ticking sounds... but you should be able to tell the difference, and what you describe sounds like it ought to be checked out.

Here's wishing you many miles of pure joy w/ your "new" scoot!
She does look really nice!
Regards,
Bob

[CatatonicBug]

No, gas is NEVER supposed to back up in the airbox. That kinda points to a carb blockage of some kind. The PRIME setting simply bypasses the vacuum lockout on the petcocks, to allow fuel to flow to the carb without the engine turning over. If fuel is flowing into the carb when the engine is not running, you have stuck float valves. I would suggest going back into the carbs and double-checking the floats and float valves, along with removing and cleaning ALL the jets (primary and main). Pay special attention to the tiny opening in the bottom of the float bowls. That jet tends to get clogged, since it sits down in the bottom with all the crud.

As was mentioned, the turn signals (front and rear) were originally square, and your seat has been customized, but other than that, you definitely have a nice bike there! If you don't already have one, you can download a manual from the link in my signature. It's been said that the '78 was the quickest of all the XS's, so be very careful once you get this thing running right. It'll get away from you really easily!

Welcome to the forum!

[Rudy]

Update.
I went ahead and did another compression test. This time with the bike warm, throttle and carb all the way open. 145-150 on all cylinders. Makes me feel a lot better. Still the same issue though. 1 and 2 are not firing all the time. It seems they start hitting around 3000 rpm and or with the choke on. This makes me think lack fuel but the plugs are a deep black carbon color that would lead me towards too much fuel. Every so often there is some poping out the exhaust from those two cylinders also. I'll probably take the carbs off again and check the float levels. I have a couple more questions for though.

1. Where can I get a front and rear master cylinder? Are there any other makes or models that are compatible?

2. I need a new rear tire. Any advice on a specific size or type that you feel is superior for these bikes?

[TopCatGr58]

Hey Rudy,

Congrats on a great find!!

If the float needle valve are not sealing properly, then the carb will flood, which can cause that cylinder to not work well especially in the lower rpms. The pilot circuit is easily clogged. However once you get above 3k rpm you're mostly in the mains, and the engine is getting enough air and can somewhat handle the increased fuel due to the stuck/non sealing float valve which causes a higher fuel bowl level=richness=black plugs!!

The float needles and seats should be removed, cleaned, inspected for a groove in the tip of the needle valve, you may be able to polish it out with some fine emory cloth or such. Use chrome polish or such on Q-tip down in the seat. Also make sure the floats actually float, the old brass ones can develop pinholes and leak...shake them to listen for something shaking inside them, then put the in pot of almost boiling water, submerge with big fork or such so you can see and watch for little bubbles coming out...if bubbles=leak!

Great compressions! Get some NEW SPARK PLUGS after cleaning carbs. ALSO CHeck to see if pilot SCREWS on top front of carbs don't have their fine tips broken off in the carb body...see tech tips for removal techniques, along with search in tech disc. forum about latest freezer technique!

Check the hose going to the left timing cover, it should connect to the metal port on the #2 carb body, not the INTAKE BOOT, but PO's get them wrong and you get too strong of pulses to the vacuum advance which can cause a rattling under the timing plate, it's a DRY chamber no oil! As mentioned, cracked vacuum line to petcock can cause poor fuel flow. ALSO put on inline fuel filters if you don't have any!! This will protect your cleaned carbs and prevent junk/debris from getting between the float needle and seat!

Aftermarket front MC's are available from sources like www.mikesxs.net and www.partsnmore.com , but the rears are not! Watch Ebay, or contact Andreas Weiss for possible replacement for rear. Mikexs is a 650 site, but many parts will fit/work on the XS11, just search here or ask here, don't write or ask Mike...due to liability issues, he's not able to say whether a part will work for anything but a 650!!

Why are you wanting to replace the MC's?? If you think the brakes are not working well vs. just the old dried up reservoirs!? Putting on new stainless steel braided brake lines will make them VERY GOOD!

Do a search for TIRES and such, tons of threads with tons of opinions, we don't want to start ANOTHER Tire thread, PLEASE! The manuals will tell you what size tires you can fit, limited with the 17" rear rim though!

[Rudy]

Thanks top Cat,
I understand the treads that are like beating a dead horse and I might be doing a little of that now. With compression now at 145-150 would I even need to check the valve clearance? Thanks for the info everyone.

[greatnw]

Congratulations Rudy! Great deal on a great looking bike.
I just went through putting my first XS1100 back together and certainly have learned a lot. I have found the long time experts here are almost always taking you down the correct path.
I'm with Ken on this one. You have to ask what systems feed 1&2 and then what is the simplest explanation for it. I'm thinking fuel supply issues since that's about the only item shared by both. I'd start with checking the flow from the petcock, then to the t between the carbs, then out of the floats before getting too deep.
I can only tell you that until I fixed the pick up coil wires under the left side cover mine would run at half power and would make you think you had fuel delivery problems. Since you have a noise there I sure would check that out. It is a pretty simple fix, really. And yours may simply have a screw or connector that has come apart.
Again, I like the work the PO did on your bike. You get the special round headlight, lower seat and bigger gas tank. Gotta love. it.
Have you seen the other Yamaha blue bike that was posted here in the last week or so? Both of you are setting a good standard.
Good luck with the fix.