Just bought my second bike an '79 XS1100 Special

[BA80]

To BA80

But while on the on, prime, or reserve, the bike runs fine, but if on prime or on it leaks, or at least I think that is how I have it, either way I'll fix the octy

Where is it leaking?

[Rustitution]

To BA80

Thanks for the tip I bet its because its not even connected, there is something that looks broken on the boot I thought it a was plug that started to rot, but it maybe the vacuum hose you referred to.

But while on the on, prime, or reserve, the bike runs fine, but if on prime or on it leaks, or at least I think that is how I have it, either way I'll fix the octy

[BA80]

Here's the whole article that goes with that picture.......

http://www.motorcyclespecs.co.za/model/yamaha/yamaha_xs1100sf_special.htm

[jetmechmarty]

Yes what Greg said. Both petcocks are plumbed through a single vacuum shutoff. Yours is likely closed as it is bypassed in "PRIME". It is installed as a safety device. If you have an accident, the tip over switch will kill the ignition and the subsequent loss of vacuum will shut off the fuel flow. This will protect you from the possibility of lying in a puddle of fuel at the scene.

Back in the day, the Special was all the rage. I have no recollection of the XS1100 being called a standard. There was a regular XS1100 and there was the Special. The Special was the actual name of the bike. It came as XS400, XS650, XS750, XS850, and XS1100. Your XS1100 Special was the first model year for a Special in that displacement. The XS650 and XS750 Specials were introduced the year before. Pictured below is how your bike would have looked when it came home from the dealer back in the day. (it seems like it was last week)

[BA80]

Nice looking SF (79 Special).

It sounds like the octy isn't working for some reason. The octy is a nick name for the vacuum operated fuel valve mounted up on top of the 2 left side carbs. All the fuel runs through it unless you put it on prime, then it's bypassed.

There is a small vacuum line that runs from the top of it to the #2 (2nd from left) intake boot. Be sure that hose is good and connected because that valve only opens when the engine is running and it's getting vacuum.

[Rustitution]

To jjz28
The Fact that they are so different is why I love it so much. So like I stated the purposes are two totally different purposes. the VFR for spirited twisties and track days, and riding with my sports bike friends, and the XS11 would be for the long highway commutes, 2 up riding, and riding with my family of harley folk

The VFR will go toe to toe with just about any liter sports bike up untill the early 2000's, and it is much faster and more nimble the XS, but the XS is a Rocket and wants to throw you off the back of the seat, (kinda scary especially with no windscreen).

I think the leaks are in the lines. the PO was riding it but not regularly and kinda let it fall into a slight state of disrepair, he needed money for college and that is why he was selling it, and I think thats why he let it go for so little.

And you are most correct I cannot short shift it like the VFR because those flase Neutrals are scary and sound like the transmission wants to eat me.

The VFR is a beast I love the 3rd, 4th, and the early 5th gens. 1991-2000, in 2001 they went to vtec and lost the gear driven cams and it just doesnt sound the same. but nothing sounds as good as a gear driven V4, i've been spoiled lol.

[jjz28]

I would keep it. You paid a good price for it. If it runs good then maybe you wont need to clean the carbs. Is the leak coming from the airbox or the fuel lines? If its the lines then it wouldn't be the float problem I was talking about. Was the PO riding it regularly? Your VFR would smoke this bike but I think you will be surprised when you crack the throttle open. DO NOT ARMOR ALL YOUR SEAT!lol Yeah, that would be bad if you opened it up and flew off the back. I can pull the front wheel on the 1-2 shift but I only did it like twice because these tranny's are not made to speed shift. You wont want to shift this like the vfr or you will be doing the dremel fix on 2nd gear if it hasn't already been done. How many miles is on it? Also, when you shift, do it firm or you will hit a false neutral and have to slow down to get it back in gear or it will grind really bad. You have 2 totally different bikes, and that awesome. I am actually looking for something like the VFR or an old FJ.

[Rustitution]

To motoman
Thanks, and thanks for clearing up what it is, the exhaust is custom because the 2 owners ago just cut it off, i'm not sure what I want to do with the exhaust yet. Ideas?

To donebysunday
Thanks I know these bikes are rock solid reliable which is what lead me to pulling the trigger. And I am a very smart rider, this bike is very different then my super sport touring VFR, This is going to be more sunday rides 2 up on scenic routes, long distance and trips.

To MPittma100
Thanks everyone says the carbs I put seafoam in the gas tank I was just going to sync them but I guess I should tear them down. it runs in the primary posistion I am thinking it may be the hoses or the clamps I'm going to look into that first. I just run it in Reserve and pray that I remember to check the fuel levels. and I changed the Oil and the Filter already, thanks

To Haywardguy929:
I payed $800 for it, I'm telling myself i'm going to fix it and flip it to justify to bikes but I doubt i'm going to sell it, this bike is awesome.

[haywardguy929]

Yeah great condition for sure, what did you end up paying if you don't mind me asking. Congrat's and yes becareful they are beasts.

[MPittma100]

Maintenance

Hi,

You should start with the carburetors. Maybe run some Sea Foam in them for a bit. Will the bike run with the petcocks on the "run" position? If they are flooding at all times, might as well take them off and go through them. Lots of post here to show you how.

Change that oil and filter before you run it. Or at least fill it up to the full mark.

MP

[donebysunday]

79 Special

I knew nothing about them but talked to my dad and did some research, my dad had one for a while and he LOVED this bike, but sold it when he meet my mom and married her.

Hi Rusty !
Welcome !
Bought my 79 Special new, ran it for 56,000 mi. and sold it to a buddy. He rode it to Mexico and twice around the Great Lakes. I've no idea how many miles he had on it when he crashed into a mail box going around a curve at 85 mph.
Watch out over running your/it's capabilities PLEASE !!!!!

[motoman]

Thanks for the advice I'll get started on the probably come winter time seems fine in reserve unless you would advise against that too.

is this a standard or a special the brakes all around are from the special.

Nice lookin' 79 special there. Only changes I see are the 4into1 exhaust, painted fenders and missin the passenger grab bar.

[Rustitution]

Thanks for the advice I'll get started on the probably come winter time seems fine in reserve unless you would advise against that too.

is this a standard or a special the brakes all around are from the special.

[jjz28]

Man, that's a good looking bike. I would say you need to take your carbs off and clean them. Sounds like a float is sticking, or the float valve is dirty. Mine did that when I got it and I cleaned the carbs and trimmed the bowl gasket all the way flush with the inside of the bowl and they work great now. No more gas coming out of the airbox. Check your oil, when these things leak gas like that, it goes into your crankcase also. Good looking bike though. That is a xs1100.

[Rustitution]

So I've been riding for a little bit and have a 1996 Honda VFR 750 which I love but my girlfriend doesn't like riding 2 up on it, and I understand. So i've been looking around and about a few weeks ago a stumbled on this XS1100, now at the time I knew nothing about them but talked to my dad and did some research, my dad had one for a while and he LOVED this bike, but sold it when he meet my mom and married her.

I went and looked at it and it was advertised as an XS1100 I still not knowing these bikes didnt know the difference. Well after test driving and negotiating price, I ended up buying and bringing it home while my parents were on vacation. I'm now in the process of restoring it with the help of my dad, and your site has been a great source of information I'm sure I will ask you many more questions in the future.












I got the engine crash guard for it, I got a back rest, I'm looking for saddlebags, and a good tank bag.

The Pro's
It runs strong
has a jet kit already done
tires are good
I got it for a steal

The not so goods
No Neutral Light
Leaks gas when the petcocks are on primary
had less then a quart of oil in it when I picked it up
all the other fluids are probably just as bad
carbs need to be tunes it runs rich my pipes are blue (probably from the jet kit and stock airbox)

the bads
nothing