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-   -   Fuel in crankcase? (http://www.xs11.com/forum/showthread.php?t=44484)

puskrat 08-12-2015 08:35 AM

Fuel in crankcase?
 
1980 XS1100G, bought about two months ago, still trying to get to shakedown.

Every time I get ready do to something, i find out about something else I have to or should do first.

Bike sat for two years. Needs new gas. Also, I want fresh oil before I fire it. First time on centerstand, I got a strong fuel smell and had thin fluid leaking through drain plug and somewhere else as yet unidentified. I have since concluded this is the infamous XS "gasoil". Now more than ever I want fresh oil before I fire it.

Local vintage medic warned me of possible overflow lines pumping fuel into the crankcase. Reading the threads on the fuel in crankcase problem, and the tech tip on O-rings from parts store. I'm not sure where to proceed. Is a petcock rebuild where I need to go? Is it a carb issue?

The previous thread I thought was helping me just stops without resolution. Lots of ideas and instructions, but no "I did it and it worked". It was a couple years ago I think.

I hate the repeat questions, but I havent seen this one answered yet, just asked. Help?

Thanks

Rat

MPittma100 08-12-2015 08:48 AM

Fuel in Oil
 
Gas in the oil indicates one or more carburetor float valves and petcocks are leaking. Need to rebuild petcocks and carburetors. When carbs are finished and reinstalled. you will need to sync them. Use only Mikuni parts in the carbs.

Change oil and filter prior to starting engine.

puskrat 08-12-2015 08:55 AM

Sounds like a definitive solution. Thanks, Pitt. I recognize that ID from the thread I mentioned. Appreciate seeing your input. IIRC, the idea was put forth to do a prelim oil/filter change with throwaway oil and after a quick run, do it again with keeper lube.

P.O. claimed to have rebuilt carbs before storing the bike. Could they have fouled somehow while sitting?

yamtom 08-12-2015 09:15 AM

po said what??
 
I dont know how well you know the po, but its a foregone conclusion, that many motorcycle sales are completed by po s that tell tales. If he says something, you must prove it correct before you rely on his word, end of story. Obviously, if its got gas in the oil, you have major work to do rebuilding carbs and petcocks. Most people get rid of octys if possible. A person of some skill can do these, but follow the guidelines closely on here, these guys are great for helping get a bike going safely.

puskrat 08-12-2015 10:12 AM

Thanks tom. I haven't torn into these carburetors yet, but my previous carb work, while not fun, hasn't left me with the dread that "major work" does.

How would I eliminate the octopi?

MPittma100 08-12-2015 07:02 PM

Fuel in Oil
 
Unfortunately, POs are full of BS on a lot of occasions. Some POs aren't really sure if a bike is running correctly or not. But they will say that it is.

After cleaning/rebuilding carbs, hook up a remote fuel source to them to verify that there are no leaks prior to reinstalling onto engine. Add 1 fuel filter to each pair of carbs. That is 2 filters total.

There are several causes of fuel system failures.

One is rust or other foreign material coming out of the tank into the petcocks. This can ultimately cause the petcocks to leak. Another cause is leaving ethanol fuel in the system for extended periods. Many POs or incompetent mechanics rebuild carbs incorrectly and are part of fuel related issues.

The XS11 carbs are sensitive to foreign material and the filters will help eliminate this problem. Rebuilding these carbs is sometimes overwhelming to the first time builder, but the satisfaction of getting them right is well worth the effort.

Start at the tank and work your way down to the carbs. Consider the complete fuel system in need of attention rather than just one part of it.

TopCatGr58 08-12-2015 08:25 PM

Hey there,

Well, your local mech/medic was a bit incorrect in that there are NO overflow lines on these carbs. There are alot of fuel lines due to the presence of the Octopus IF it is still in place. If so...then it is also not working right. IT is the vac. shut off valve AFTER the petcocks..the special petcocks are just gravity feed type.....they then flow into the Octy...and it's supposed to shut off the fuel flow when the engine is OFF=no vac. to the vac. valve in it...but that valve can get stuck/gummed up, or the metal behind it and spring can rust/corrode, etc.!

SO...there's a chance that the petcocks may actually still work....but they may have been left in the ON position which then leaked past the Octy....and THEN the carbs needle float valves also failed/leaked for a variety of reasons. The PO may have rebuilt/clean them but then stored with fuel in carbs/tank...and old gas forms varnish/gum which can cause the float needle valves as well as the Octy to gum up/stick and leak.

Then, when the float needles stick..leak the bowls fill up and overflow into the throat of the carb body...which then can flow forward thru the carb throat into the intake and then past the intake valve, the pistons/rings and into the crankcase=gasoil! :eek:

Most petcock rebuild kits for specials usually has the Octy rebuild parts also. But as was said....some folks thinks it's too much clutter and unnecessary complexity and so they remove the Octy....then just cap off the front petcocks nipple, and then run the petcocks directly to the carbs with inline filters...and then just remember to MANUALLY turn off the petcocks when they park for extended times. For just short parks....properly working carbs will shut off the fuel if the petcocks are left in the ON position.

Another leak source aside from the float needles are the needle seats and their O-rings. You can also test the petcocks by just removing the fuel lines from the octy, run to a catch cup/bucket and then test the function positions of the petcock handle...should flow in RUN and Reserve, not in OFF, and the prime position flows out of the FRONT capped nipple...redundant without the Octy. With the Octy....it provides a bypass to help Prime/fill the float bowls gravity feed way.

T.C.

Prisoner6 08-13-2015 06:03 AM

I think what first needs to be determined is:

Which model XS does Rat have? His profile simply says "1980 XS1100", and in his original post in this thread, he indicates the bike is a 1980 XS1100G.

In none of his posts do I see any other indication which model he has.

If it is a G (Standard)... then it has vacuum-controlled petcocks, and no Octopus to contend with (only Specials had the Octopus).

Rat, is your bike a Standard (bigger/more square-ish tank) or a Special (smaller/teardrop tank)? This is one possible way to tell (assuming the tank hasn't been swapped).

Once we know for sure, then we can discuss Octy vs. no Octy, and how to proceed.

Prisoner6 08-13-2015 06:32 AM

Quote:

Originally Posted by Prisoner6 (Post 470444)
I think what first needs to be determined is:

Which model XS does Rat have? His profile simply says "1980 XS1100", and in his original post in this thread, he indicates the bike is a 1980 XS1100G.

In none of his posts do I see any other indication which model he has.

If it is a G (Standard)... then it has vacuum-controlled petcocks, and no Octopus to contend with (only Specials had the Octopus).

Rat, is your bike a Standard (bigger/more square-ish tank) or a Special (smaller/teardrop tank)? This is one possible way to tell (assuming the tank hasn't been swapped).

Once we know for sure, then we can discuss Octy vs. no Octy, and how to proceed.

Also, do your petcocks have an OFF position? As delivered from the factory, Special petcocks had an OFF position, Standard petcocks did not.

puskrat 08-13-2015 07:52 AM

Yes it's Standard. Apparently *I* am special.
 
Sorry Guys. The profile was created when i didn't really know much about what was going on. Don't let that imply I know a lot now! My XS is an XS1100G, a standard, with no "off" position. That spleens why I had no context for working on the octopus, other than seeing references in prev threads to "the octy" I have a Yamaha Service Manual and have d/l'ed some references from links here on XS11.com, and am still familiarizing myself with my machine a little bit at a time. You guys have already been a big help, keeping me from making serious mistakes, and smacking me in the face with some reality. Keep it coming!

Humor.....My gf (also the landlady of my motorcycle storage garage) is a high school music teacher, and you all informed me of the petcock problem right before I went to her chorale reunion cookout. She asked how shop day went and to avoid the giggles, I had to use the term "fuel shutoff valve" several times rather than the more typical term.

I know to get Mikuni parts. I know a Mikuni model XX for an XS1100 (does the G matter in this case?) isnt the same as a Mikuni XX that goes on a randomjapcycle XXXX. How do i pick out what to get? Is that why Mikes has kits AND specific individual parts?

bikerphil 08-13-2015 08:02 AM

You can always call them 'fuel taps' to avoid embarrassment. Don't want those girls to think you are talking about roosters, lol.

Yes, the year matters when obtaining carb parts, the 78-79 bikes use different carbs than the 80-81's do.

Prisoner6 08-13-2015 08:32 AM

OK, Rat -

So, you have a Standard ... which means you have vacuum-controlled petcocks instead of the Octy.

THIS is the kit you will need to rebuild those leaky petcocks:

2X Yamaha XS1100 Petcock Rebuild Kits

BUT, as mentioned, you also have one or more leaking float needles and/or seats ... so, you will need to service/rebuild your carbs as well.

You should be able to buy the needle/seat assemblies HERE:

JetsRUs

Someone here will be able to help you determine the correct needle/seats that you need for your G (later carbs).

And yes, concerning these carbs, always use Genuine Mikuni parts, especially when it comes to jetting.

puskrat 08-13-2015 08:39 AM

thank you phil. If that's the only difference I should be able to piece together what I need.

The rooster thing has a certain irony at that school: A rookie teacher, known for her, shall we say, "sociability" had the French Club T Shirts printed with a large black silhouette of a rooster. She said she loved hers so much, so thought everyone should have one.

puskrat 08-13-2015 03:58 PM

Downloaded a Service manual that appears to be a 78-79 edition but with supplements for 80-81. The carburetor section Charts an XS1100 E, F, and SF. The E uses a different starter jet than the other two. and the SF uses a different carb. I read (I believe on this forum) the E is the European designation for the G) Does this mean I need the BS34-11 2H7-00 carburetor and the No. 40 starter jet specced for the E?

Thanks again for everyone who's helping and not tripping the stumbling newb.

puskrat 08-13-2015 04:49 PM

Never mind.
 
My hardcopy Factory Svc Manual tells me other information. Glad I didn't follow that rabbit trail far from the monitor.

Prisoner6 08-13-2015 05:16 PM

Yamaha used the letters E through H to designate model years 1978 through 1981, respectively.

So, an XS1100E is a 1978 Standard. They added the 'S' to the model year letter to indicate a Special, i.e. SF, SG, SH ...

HERE is a jetting guide for the XS11:

Carburetor Facts - Models and Jetting

As Phil mentioned ... basically there are 2 different types of carbs used on these bikes ... '78-'79 and '80-'81.

Depending on what year carbs you have, and whether your bike is Standard or Special, there are subtle differences between each year, even within the 2 basic types.

I'm assuming your carbs are indeed '80G carbs, and haven't been swapped out for different ones.

There's a lot of 'swapping of parts' that goes on with these bikes, from tanks to seats to carbs to final drives to ... you name it.

puskrat 08-14-2015 04:13 PM

re: swapping of parts.
 
I was informed/warned about that. I got a lot of spare parts, which at first made me think "well he picked out only the right stuff for the machine", but now makes me wonder if he just tossed everything in their. guess I need to start IDing years models and carb bodies (among other) going back to the jetting resources for now. thanks everyone, have a great weekend, and be safe

Prisoner6 08-14-2015 05:06 PM

Hey, Rat ...

You can easily find out exactly which carbs you have ... look HERE:

Carb Identifier Guide

And HERE is a guide to the serial #'s and model ID's for our bikes:

Serial Numbers/Model Designations/Factory Colors

puskrat 08-17-2015 09:52 AM

Again, thank you, gentlemen. Tomorrow is my day off (aka shop day), and I plan to pull the carbs and diag the petcocks (I guess I know one is bad and need to know which) Printing the carb identifier, the rebuild tutorial, and the jet identifier to take with me. (wi fi doesnt reach to the garage, ugh)

MPittma100 08-17-2015 02:46 PM

Quote:

Originally Posted by puskrat (Post 470846)
Again, thank you, gentlemen. Tomorrow is my day off (aka shop day), and I plan to pull the carbs and diag the petcocks (I guess I know one is bad and need to know which) Printing the carb identifier, the rebuild tutorial, and the jet identifier to take with me. (wi fi doesnt reach to the garage, ugh)

The fuel getting into the oil gets there when a carburetor float valve is leaking. If a petcock is also leaking, that much more fuel gets into the oil. You need to verify which carb(s) is leaking. Make that repair. You should rebuild both petcocks regardless. If you have not rebuilt any of these fuel system parts before on this bike, it is time to do all of them. Do not leave ethanol fuel in the bike after rebuild for any length of time.

puskrat 08-17-2015 04:24 PM

on the stump
 
hate to be soapboxy, but I hope to not allow any ethanol in my tank period.

puskrat 08-21-2015 10:20 AM

Because it simply is not allowed to be easy
 
after looking into some oddball stuff, I found out from the PO my carbs have been swapped for 1978/79 models. Before you can do anything, you always have to do something else.


edit because reasons

MPittma100 08-21-2015 09:25 PM

Older Carbs
 
Quote:

Originally Posted by puskrat (Post 471251)
after looking into some oddball stuff, I found out from the PO my carbs have been swapped for 1978/79 models. Before you can do anything, you always have to do something else.


edit because reasons

No matter which year carbs you have. They all can eventually leak if not maintained properly. Sitting for years, ethanol gas, not so good PO rebuilds all contribute to failure. Get the right Mikuni parts and have at it.

puskrat 09-03-2015 09:27 AM

and so it goes
 
Guys....I'm about to get into the carbs......

I've 79 carbs on a 1980 G. Standard bike. My thoughts: the 79 carbs are jetted differently than the 80's. What changed to require the revision? How should I jet my 1979 carbs on my 1980 bike? Any other settings I need to be especially sensitive about? Should I just chip and melt and carbs that are on it and rebuild the "extra" 1980 units I got in my spare parts bonus bins?

dbeardslee 09-03-2015 09:40 AM

Quote:

Originally Posted by puskrat (Post 472669)
Guys....I'm about to get into the carbs......

I've 79 carbs on a 1980 G. Standard bike. My thoughts: the 79 carbs are jetted differently than the 80's. What changed to require the revision? How should I jet my 1979 carbs on my 1980 bike? Any other settings I need to be especially sensitive about? Should I just chip and melt and carbs that are on it and rebuild the "extra" 1980 units I got in my spare parts bonus bins?

My brother has an 80G with 78/79 carbs, and they work just fine. On the 78/79 carbs the pilot tower is plugged, and the pilots draw their fuel up through the main jet tower via a little cross shaft. On the 80/81's there's no plug on the pilot jet tower, so the pilots draw their gas directly from the bowl, hence the different main jet size. And the 80/81's had plastic floats while the 78/79's have brass. Never, ever put compressed air on the fuel or vent lines on the 78/79's while the bowls are in place, thinking that you're going to blow out the system. You'll crush the brass floats almost instantly.

Personally I like the 78/79 carbs better, but you do have to be more careful with the mixture screws. Never, ever screw those mixture screws down tight or you run the risk of breaking off a tip, and they're REAL boogers to get out once they've snapped off. The 80/81 mixture screws are usually capped, and you have to get the caps off before you can do anything with 'em. You also need a smaller screwdriver to get down in there to adjust the mixtures once you've got the caps off. Mixture screws on the 78/79's are exposed, and much easier to get at.

The way you need to jet those carbs depends on your intake and exhaust. How's your bike setup? Stock air box or pods? Stock exhaust, 4/2, or 4/1?

motoman 09-03-2015 10:53 AM

As usual, didn't read over the previous postings, so here goes. Actually FOUR types of carbs used on the XS11's. 78 had one type, 79-8-82XJ's had four type. Differences from 79-82 ARE: Standards had different jetting than Specials due to metering rod differences which required differences in main jetting. XJs had AGAIN differnt metering rods which required even diferent main jetting. Hope that made sense to those questioning. 81-82 had different float bowls with the drain seat screws on sides od bowls. This REQUIRED fuel levlels to be checked while idleing using a clear hose from bottom drains swung up beside tops of carbs. So, lots of differences there between year models and Special and Standard models. Do NOT confuse the jetting depending on yr. model of carbies;):).

DiverRay 09-03-2015 11:38 AM

OK here is what should work, and what you will need.
1. Do ONE carb at a time. You can pull the top and float bowls, but keep everything together so the parts go back into the carbs they came out of.
2. 4 new seats/needles from Mikuni source, USE ONLY MIKUNI!!!
3. If bad, replacement bowl gasket.
4. Probably need new jets, as I'll guess replacements are aftermarket. Go with stock jets for a '79 standard IF the jets in the carbs do NOT have the mikuni mark.
5. CLEAN everything, but DO NOT put carb bodies into a tank of carb cleaner! I use an ultrasonic cleaner with pinesol and water mix. Cleans everything pretty well.
6. Measure twice on the float levels, and both floats.
7. LIGHTLY seat the idle mixture screw! Use the screwdriver shaft to turn the screw so you don't overtighten it, then back it out 2 turns to start with.
8. Bench sync carbs
9. Bench test floats! put a fuel tank above the carbs, and make sure they don't leak. Leave it for about 1/2 hour, in case you have a float with a pin hole. BTDT

puskrat 09-03-2015 02:31 PM

and I shall.....
 
compiling the feedback....

Only recommendation I see on 79 v 80 carb bodies says go with 79s, even if it's not a strenuous opinion.

The jets are different because the system is different. That makes good sense to me. I'll inspect the bodies to be sure I'm in the right ones at the right time. Just need to make sure the number one is on cyl one, etc.

cleaning with pine sol; check

no compressed air through attached hoses. check

mikuni parts. recheck

one unit at a time. check.

I'm going to avoid ethanol like the proverbial plague (ethanol is theft - a dangerous thing to say in Illinois). BUT....if I'm out on the road and have to, I have to. Are there ethanol-safe O-rings That could be installed? Speculation has arisen my carbs may have in fact been rebuilt and then E90 sitting in the system caused the leakes.

DiverRay 09-03-2015 02:40 PM

Just do NOT put in E90!!:eek::eek: The "normal" fuel here is 10 to 15% E, and my bikes run OK on it. I would NOT put E90 into anything except a race engine that was set up for it. You should not need any special seals, as the biggest problem from the fuel is it will eat the carb bodies if left too long.

dbeardslee 09-03-2015 03:09 PM

I'll add something on gas. The non-ethanol stuff I've heard of seems to be premium, which I assume is the 91-92 octane variety. There seems to be a lot of confusion when it comes to octane rating, and lots of folks seem to think higher octane means more explosive gas. In actual fact the octane rating is a measure of the compressibility of the gas, and unless you've got a high compression motor high octane generally causes more problems than it solves. It tends to gum stuff up. I run the lowest octane I can without getting pre-ignition, and for my 79F that's 87 octane. I've been running it with 10% ethanol since I bought Betsy in 2007, and haven't had any problems with it.

But if I could find non ethanol gas in 87 octane I'd be on it like a monkey on a cupcake. The information I've seen on gasahol seems to be that you can expect about 10% worse mileage with 10% ethanol than straight gas. Which seems wierd considering the powers that be would like us to believe it's making the gas go farther. Looks to me like we're just paying more for less.

dbeardslee 09-03-2015 03:13 PM

Quote:

no compressed air through attached hoses. check
That's with the carb bowls in place. With them removed you can blow compressed air through the lines with no problem.

puskrat 09-03-2015 03:41 PM

very well put beardslee. It was actually an Iowan, believe it or not, who coined the ethanol is theft line. I sold cars for eight years, and in the middle of that I spent a boring day in the showroom reading through EPAs fuel mileage guide. Flexfuel vehicles get worse mileage than conventional even on E90, and the numbers work out to an increased consumption of petroleum fuel when one takes the time to do the algebra. But they told us not to worry about algebra, it won't be useful.........

Also I failed to respond to a question. I have stock pipes and stock airbox. I have toyed with some ideas, as one of the mufflers is wounded, but I want to get on the road THEN start changing things.

puskrat 09-03-2015 03:42 PM

Oh and I appear to be misusing jargon
I thought e90 was 10% ethanol...the "std" mixture

So Just look at everything I've said, do a "find" e90 and "replace" with e15.
Thank you

dbeardslee 09-03-2015 04:05 PM

Quote:

I have stock pipes and stock airbox.
Then jetting should be 137.5 mains with 42.5 pilots with the '79 carbs. Trying to find the slide needles is like looking for a needle in a stack of needles, so you'll probably have to stick with what you've got. It's a good idea to take the slides apart (although you'll need some deep reach snap ring pliers to do the deed) to make sure the clips are in the middle slot and that they're properly assembled. Might check the needles for markings too - if there are any they should read 5GZ6.

puskrat 09-04-2015 09:08 AM

Quote:

Originally Posted by puskrat (Post 472699)
Oh and I appear to be misusing jargon
I thought e90 was 10% ethanol...the "std" mixture

So Just look at everything I've said, do a "find" e90 and "replace" with e15.
Thank you


Edit because more stupid:

So Just look at everything I've said, do a "find" e90 and "replace" with e10.

puskrat 09-15-2016 04:22 PM

I heard a Whinny
 
Not exactly beating a dead horse, but how does the gasoline leaked past the float valves get from the carburetor into the crankcase? When i was describing this scenario to a Harley guy, he thought bad rings. I'm thinking not, but I know the mixture will be thinner than the oil those rings usually deal with....

dbeardslee 09-15-2016 05:09 PM

Quote:

Originally Posted by puskrat (Post 490914)
Not exactly beating a dead horse, but how does the gasoline leaked past the float valves get from the carburetor into the crankcase? When i was describing this scenario to a Harley guy, he thought bad rings. I'm thinking not, but I know the mixture will be thinner than the oil those rings usually deal with....

Some of it drips out of the airbox, and some of it goes out the other end of the carb, into the cylinder, past the rings, and into the oil. Rings don't exactly have a waterproof (or gas-proof as the case may be) seal.

MPittma100 09-15-2016 06:27 PM

Quote:

Originally Posted by puskrat (Post 490914)
Not exactly beating a dead horse, but how does the gasoline leaked past the float valves get from the carburetor into the crankcase? When i was describing this scenario to a Harley guy, he thought bad rings. I'm thinking not, but I know the mixture will be thinner than the oil those rings usually deal with....

Specifically by the ring end gaps. All engines that are in good running condition with good compression will have normal 10%-15% cylinder leakage. This leakage is what gets into the crankcase by the ring end gaps. That is why the crankcase has to have a breather. Otherwise, you blow a gasket or seal. There is such a thing as gapless piston rings, but are typically for racing.

To easily prevent crankcase flooding with fuel, simply put a 2X4 under the front wheel with bike on center stand. Leaking fuel will run into air box instead of the engine.

HalfCentury 09-15-2016 07:22 PM

My XJ650 had gas in the oil when the PO delivered it to me. Upon disassembling the carbs, I found rust particles in every nook and cranny of the carbs. The tiny rust particles can lodge between the float needles and the seats causing the gas to get by the float needles and eventually into the crankcase.

After I cleaned the carbs and re-assembled, I installed lawnmower cheapo fuel filters and never had a problem with gas getting into the oil of that bike. I ran that bike 4 years and the carbs never needed any attention during that time.

motoman 09-17-2016 10:39 PM

Quote:

Originally Posted by puskrat (Post 470395)
Sounds like a definitive solution. Thanks, Pitt. I recognize that ID from the thread I mentioned. Appreciate seeing your input. IIRC, the idea was put forth to do a prelim oil/filter change with throwaway oil and after a quick run, do it again with keeper lube.

P.O. claimed to have rebuilt carbs before storing the bike. Could they have fouled somehow while sitting?

nope........fouled up by mis-guided PO;).


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