Greetings from Central Indiana!

[Munky]

Hey guys and gals! My name is Cory, and I'm the proud owner of a 1981 Yamaha Midnight Special XS1100L that I inherited from my father when he passed. I was only able to ride it a handful of times before the carb issues that I'm still experiencing, and I'm hoping you guys can help point me in the right direction before it drives me off the deep end.



Quick synopsis:

My dad had the bike in storage for years due to random things needing replaced. Once he passed, my uncle brought it down from Milwaukee, WI to Owensboro, KY and had a local bike shop tinker with it until it was alive and mobile again.

When I picked it up from him, it ran and rode great, the only issue was I had to leave it on half-choke or it would die at idle. I was told the carbs needed to be cleaned soon. I rode it 6-7 times, until I moved the bike and gas came flowing out of the airbox, thanks to a sticking float. Time for that cleaning!

Fast forward to a few months ago - I got the carbs out of the bike, and took them to a local shop here to get cleaned. They charged me $165 parts/labor, which I thought was a great deal, until I brought it home and the choke wouldn't even open. I took it back, they got it to open/close, but now the choke won't stay open when I pull it like before - I have to wedge something in there to hold it open.

Once I got the carbs back in the bike the 2nd time, I had to deal with the bike sputtering and not even starting. It would fire up once, sputter, pop, and die. I tried changing the lines around on the octopus, thinking I had mixed something up, and now every time I start the bike it revs up instantly.

I was told to check and make sure it's not the throttle cable, so I disconnected the cable and it still rev'd up. I took the carbs back out and the butterfly valves aren't open even a little - they look just like they did beforehand.

My friend suggested that they might have dipped the carbs intact instead of taking them apart, potentially ruining the seals/gaskets inside the carbs. The owner of the shop told me that nothing they did should affect the way it runs..so I'm lost here.

Right now, the carbs are back on my bench awaiting the next step.



I'm hoping that someone here can point me in the right direction, because carbs are like witchcraft to me.


Thanks in advance for any advice you guys can provide, and I'm looking forward to being a part of this community!

[crazy steve]

Welcome!

You got off cheap for only $165 to find out that most shops can't work on these... I don't know of anyone who has had any luck with a shop rebuild...

Almost everything you need to know about XS carbs....

http://www.xs11.com/forum/showthread.php?t=35964

http://www.xs11.com/forum/showthread.php?t=36017

It's a sure bet they didn't buy any new parts other than bowl gaskets if those, so chances are very good you'll still need to get rebuild kits. Preferred sellers are Georgefix (on eBay, he also has a non-eBay store), Z1 Enterprises, Sirius, PartsNMore.

These aren't that tough to do at home, but you have to be very thorough in the cleaning. If you suspect any crap in the tank, that should be cleaned out too. After the carbs are rebuilt, a on-the-bike carb sync is needed (which is probably the reason for your high idle).

These are great bikes when brought up to spec, and pretty low-maintenance once you do. But it can be a bit of a challenge to clear up long-term neglect, but you've come to the right place!

If you don't have a manual, you can download one here: http://www.ringler.us/family/mybike.html

[DGXSER]

Steve pointed you to the right threads on figuring out which carbs you have. Since you know the bikes history pretty well, it most likely has the stock carbs for the 81 models.

The issue with dipping the entire carb bank is the butterfly seals. Those can be ruind by the carb dip stuff. Which can then lead to vacuum leaks, which lead to high revs.

As to why the choke will not stay open, that is because they lost a few parts. When you pull the rod out that the choke valves ride on and you pull when you pull the lever, there is a small ball bearing with a spring behind in a small tunnel on the number one carb behind the lever. it rides in three indents in the rod. When you pull the choke lever out, that ball pops into the indent to hold it open. As you move it closed, the indents slide across the ball locking it into place.

A good cleaning, new float needle valves and seats, a good bench sync and then a good running synch should get her running like a scalded dog.

[natemoen]

Welcome. These guys got you started on what to do.

If you need any help let ne know. I am right up on the north east edge of indy, probably 20 minutes away.

[Munky]

Thanks for the quick replies!

Welcome!

You got off cheap for only $165 to find out that most shops can't work on these... I don't know of anyone who has had any luck with a shop rebuild...

Almost everything you need to know about XS carbs....

http://www.xs11.com/forum/showthread.php?t=35964

http://www.xs11.com/forum/showthread.php?t=36017

It's a sure bet they didn't buy any new parts other than bowl gaskets if those, so chances are very good you'll still need to get rebuild kits. Preferred sellers are Georgefix (on eBay, he also has a non-eBay store), Z1 Enterprises, Sirius, PartsNMore.

These aren't that tough to do at home, but you have to be very thorough in the cleaning. If you suspect any crap in the tank, that should be cleaned out too. After the carbs are rebuilt, a on-the-bike carb sync is needed (which is probably the reason for your high idle).

These are great bikes when brought up to spec, and pretty low-maintenance once you do. But it can be a bit of a challenge to clear up long-term neglect, but you've come to the right place!

If you don't have a manual, you can download one here: http://www.ringler.us/family/mybike.html

Yeah, I'm sure they didn't buy any new parts too - my receipt was 160 labor, $5 worth of carb cleaner. I had planned on getting a rebuild kit, since I don't personally know the last time it was done.

They may not be tough to some people, but I don't trust myself to do this. If I screwed up the carbs by doing something wrong I would never forgive myself. Not to mention I don't even have a workbench in my garage to do this on. I need a workspace or something. Also, I wouldn't really call it a high idle, because it doesn't idle at a high RPM, it just revs up to redline instantly, and I have to kill the ignition to stop it.

I've found a few online manuals, and the diagram on here for the octopus, but thank you for providing another link! You can never be too informed.

Steve pointed you to the right threads on figuring out which carbs you have. Since you know the bikes history pretty well, it most likely has the stock carbs for the 81 models.

The issue with dipping the entire carb bank is the butterfly seals. Those can be ruind by the carb dip stuff. Which can then lead to vacuum leaks, which lead to high revs.

As to why the choke will not stay open, that is because they lost a few parts. When you pull the rod out that the choke valves ride on and you pull when you pull the lever, there is a small ball bearing with a spring behind in a small tunnel on the number one carb behind the lever. it rides in three indents in the rod. When you pull the choke lever out, that ball pops into the indent to hold it open. As you move it closed, the indents slide across the ball locking it into place.

A good cleaning, new float needle valves and seats, a good bench sync and then a good running synch should get her running like a scalded dog.

They do have the original carbs, the bike has 17K original miles. My dad bought it brand new!

I even told the owner of the cycle shop that the choke used to stay open and doesn't know, he told me it was because of the "gunk buildup" and it's working as it should now. I'm currently trying to get my money back.

Welcome. These guys got you started on what to do.

If you need any help let ne know. I am right up on the north east edge of indy, probably 20 minutes away.

I can guarantee I will need help, but I don't want to put all that on you. I don't even know where to begin when it comes to rebuilding these - I couldn't even take the caps off the top of the carbs without stripping the screws, I'm seriously afraid of screwing something up.

[natemoen]

Everyone strips those screws out, they are not really phillips head screws they are JIS which is a bit different. You should change out all those screws to a socket head cap screw with the allen head in it, preferably in stainless steel.

I would much rather give you a hand than have you break stuff and regret it later. I am free all day tomorrow (Wednesday), I will PM you my number if you want to give me a call.

[GLoweVA]

It sure is nice to have local XSives!
I can't count the number of times TC has helped me out, or the number of times I've helped Nitengale (john).
Plus, once the bikes get running, then it's time for local rides!

[Munky]

Everyone strips those screws out, they are not really phillips head screws they are JIS which is a bit different. You should change out all those screws to a socket head cap screw with the allen head in it, preferably in stainless steel.

I would much rather give you a hand than have you break stuff and regret it later. I am free all day tomorrow (Wednesday), I will PM you my number if you want to give me a call.

Thanks for the offer! I would much rather wait until I have all the necessary parts before asking you for help.

Do you have a recommendation as to where I can get those socket/allen head screws?

[Munky]

I've looked up the carb kits on ebay, but which one would work for my bike? These say 1980, but I have an '81. And mine's an XS1100L.

I just want to be sure I buy the right ones.

http://www.ebay.com/itm/4x-YAMAHA-19...item2c70d93a30

http://www.ebay.com/itm/4X-YAMAHA-19...item2ec93b12c7

[natemoen]

Problem is, you don't know if you need carb kits till you take them apart and look....

No sense dropping money on stuff you don't need.

[Munky]

Problem is, you don't know if you need carb kits till you take them apart and look....

No sense dropping money on stuff you don't need.

Hm, I guess I didn't think of it that way.

[GLoweVA]

Problem is, you don't know if you need carb kits till you take them apart and look....

No sense dropping money on stuff you don't need.

+1 on what nate said, about the only part that you MAY need is new bowl gaskets. If they have been on there forever, they may break during disassembly (ie taking the bowls off) You can be careful and if they come off okay, you can reuse them.
The jets are made of brass and can be cleaned usually with just carb cleaner and sometimes with some brasso and a soft toothbrush if they're really green.

Like others here have said, the diaphram tops and carb bowl screws are JIS (Japanese Industry Standard) not regular phillips, so find a phillips that fits really snug and use some PB blaster (or equivalent pentrator) to loosen those suckers up. Don't worry too much if you do strip the + out of the head, you can just take a dremmel cut off wheel and make the head a standard (-) and use a regular screwdriver then. Once it's off, then you can put new fasteners in there.
You don't have to take each carb off the bank of 4, just take the pieces out of the bank. Try to keep the parts separate so you know which parts went into #1,2,3 or 4.
I usually take the bowls off first and then put the parts (jets, spring, needle, etc) in the bowl and let them soak a little in some carb cleaner in the bottom of the bowl.

Besides using the tech threads on this site, I found a PDF that has nice pics.
They do take the carbs apart from the bank, but like I said, you may not have to.
http://www.mtsac.edu/~cliff/storage/...d_Tutorial.pdf

[Varnae]

Hey, I know this is a somewhat old thread, but if you need help Munky, I'd be happy to help you out. I don't have an xs anymore but do have a good amount of experience with rebuilding carbs as I did it on all 3 xs's that I had and on my current yzf. If you want help, just let me know. I have some garage space, a workbench that we can work on and just about any tool we might need with the exception of a carb sync tool.

I'll pm you my email addy and my cell number in case you want to get in touch with me. I live near Morse Reservoir.

[MPittma100]

Model Number

I've looked up the carb kits on ebay, but which one would work for my bike? These say 1980, but I have an '81. And mine's an XS1100L.

I just want to be sure I buy the right ones.

http://www.ebay.com/itm/4x-YAMAHA-19...item2c70d93a30

http://www.ebay.com/itm/4X-YAMAHA-19...item2ec93b12c7

Hi Munky,

I am sure that with all of this help you are getting, everything is going to work out fine. The shop who built them for you originally don't know their as_ from third base. The majority of the shops do not know enough about these carbs to help you. For some reason though, they take your money and claim that they do know what they are doing?

I believe that the correct model designation for your bike being a 1981 MNS is 1981LH. I believe that most replacement parts are shared between the Special and the MNS. The Standard model is 1981H, and the (regular) Special is 1981SH.

Good luck with getting her up and going.

MP

[trbig]

Several weeks have gone by... What happened to the Munky?

Maybe Nate scared him off. He's a bit of a shady character..