Guides or rings causing the smoke?

[jurgenkoppen]

Hi,
Last summer I bought a very pretty 80 xs11 in Chicago, cosmetically she lookes like new.
However, before I flew out, to drive it home to the British Columbia's West Coast, the previous owner adjusted the cam chain tension. He wanted to have her all prepped for my 2500 mile journey. Something went dreadfully wrong though:
I received a call 4 days before my booked flight , that the bike was kaputt, due to bend valve stems. Obviously the chain jumped a tooth etc.
However, making long story shorter, my flight was booked, I wanted the bike, so we got her fixed in a Chicago shop: mega $$$$$$.
On my way home I noticed a myriad of other flaws: I got to repair the charging system on the fly, at one point in Montana I had oil all over my pants because of hairline cracks in the valve cover. I had a cylinder cut out because of weird plug boots, etc etc.
As it turned out, despite the showroom cosmetic condition, the previous owners had futzed with so many aspects and did so many silly things, it would take too long to all describe it.
The main one however, was: to chrome engine covers, and put them back on WITHOUT the gaskets. Hence the crack in the valve cover, and multiple oil leaks, one warmed up.Which I did not notice on the road, until the oil warning light came on.....uuughh
Final upshot: the bike is now smoking, with less than 15000 miles on it.
I am trying to figure out, if it is the valve guides, or is it the rings?
It smokes fiercely blue upon cold start, but once warmed up it is not noticible anymore. #4 plug is black with oil. Uses a quart of oil now on 200miles.
My question:
Is there a way to test with a compression tester conclusively, which problem it is,valves or rings, or both?
If it is the valve guides only, I might get away without doing the rings, which is of course less daunting. I even heard talk of dropping in new valve guides without taking off the head.Is that possible?
Any thoughts on this?

Thanks, Jurgen

This is the 3rd XS11 , my previous ones never gave me any trouble at all, they were so dependable, it bordered at boring :-)

[TADracer]

If it is rings it will smoke while cruiseing, accelerating, etc. If it is seals it will smoke when the throtle is closed and you are decelerating since vacuum goes sky high under the seals then.

A leak down test is much more informative than a straight compression test will be able to tell you exactly if it is rings or valves.

[skids]

Re: Guides or rings causing the smoke?

I have always wanted to ride a bike many miles to home from a seller's house, but I have never had the guts. The problems you experienced are the sort of things that I feared. At least you were told about the bent valves...

Originally posted by jurgenkoppen
This is the 3rd XS11 , my previous ones never gave me any trouble at all, they were so dependable, it bordered at boring :-)

[jurgenkoppen]

TADracer,
thank you for the reply.
Excuse my ignorance, but how to I perform a leak down test?
I have not heard of this procedure before.
Here also is a picture of the black beast.
You might see that there was method to my madness to fly to Chicago to get by a $2000 bike, especially in view of headers and stock pipes being in mint shape:

The black beast:

[jurgenkoppen]

Hey Skids,

Yeah, I guess I based my decision for the ride on the fact that my previous xs11s had carried me clear around the continent without so much as a hick up.

Plus, as you can see from the picture above, the bike looks brand new.
The guy who was selling it, seemed very particular, even made a little video of the bike running for me ( before the fatal adjustment) and was measuring the remaining tire tread in 1/64" increments.

Anyways, I also needed a road fix, and I am fairly confident that I can handle whatever circumstances might throw at me. Now that attitude got tested , alright...
Cheers, Jurgen

[prometheus578]

"I'd say rings..."

Especially after your statement about the oil light coming on.
But... let's play for a while.
Might not be any big ring damage.
Recall that the bike just had valve work done to it. Assuming there's no damage to the rings.. it's possable that a valve seal may have been incorrectly replaced... or may have popped off, hence the smoke.
There's one possability.
But that oil light scenario brings up others.
A leak down test fills the cylinder with pressurized air. There is a guage which registers what % of leakage you have. If you have a mechanically significant leak, you'll hear the air escaping.
Air out the carbs... bad intake valve.
Air out the exhaust... bad exhaust valve.
Air out the crank case breather(or up through the cam chain cavity if you have the valve cover off)... bad rings, etc.
First, start with a compression check and see what that shows.
A simple Leak Down tester can be made from the compression checker, provided you have a compressor in your garage.
Bring the cylinder to be checked to TDC.
Remove the valve from the compression tester hose. It's like a tire valve, though the spring is a lot weaker(they cannot be interchanged for this reason)
Set your compressor to around 90/100 pounds.
Screw the modified hose into the plug hole and connect the air supply.
You have no gauge to check the reading of... but if there's damage somewhere, like the rings, you should hear air hissing.

Was it smoking when you got it from the shop, or did it start halfway home, or only after the oil light thing?

Any work on the head: valves, guides, seals, is a hell of a lot easier with the head off.

[TopCatGr58]

I'm with Prom,

Do a simple comp test..remember warmed up engine, fuel OFF but THROTTLE WIDE OPEN, ALL spark plugs OUT for ease of spinning engine.

I would inquire on whether the SHOP that fixed the valves put in new valve stem oil seals or not? You can remove the valve springs and replace the seals with the head still on the engine, but takes a bit more work keeping the valves in place.

Also, how's the fuel petcocks and carb float valves? Any possibility of fuel contamination of the oil??

BTW, which valves/cylinders were bent? #4? coincidence?
T.C.

[jurgenkoppen]

TC and Prom,
they replaced all four intake valves and my invoice shows also 4 valve stem seals.
The bike required about 5 or 6 quarts of oil over the 2500 mile trip, but that also might have been result of the various oil leaks, which I did not notice early enough, since they happened while riding.
The real serious, visible blowing of smoke did not start until about two month later, at home. I recall that I had taken out the carbs to free up the choke passages, which were plugged.
I put the carbs back in, and right after that, test driving it up my hill, I noticed the plume of smoke behind me. Maybe some carb cleaner still in the carbs ended up breaking my oil film ...and caused a valve seal to pack it in?
That was also start of the oil fauled plug on #4

Anyways, I will take all the tests you guys recommended, and fill you in with the results, as soon as I have them. Tomorrow is Sunday, and I have time in my compressor equipped shop.
Thanks on giving me the proper compression test procedures, I was not sure there.

Also, I suppose that for the 'leak down test', it would be better to take off the valve cover? Because if oil is leaking from the cam shaft area through the valve stem seal, I 'd guess the air would escape through that seal into the cam shaft chamber??
The valves might still be closing ok, so the passages to the exhaust and carb would be closed, would they not? Or am I missing something here?
Thanks a million for your help to get me up to speed.
I have another engine, a '79 with real good compression,to put into the bike. But I thought I should get all the tests done on the old one while still in the bike, so I know what repairs I am facing.
Test results tomorrow. Thanks again, Jurgen

[prometheus578]

Because if oil is leaking from the cam shaft area through the valve stem seal, I 'd guess the air would escape through that seal into the cam shaft chamber??

No.
With the piston at TDC (on the compression stroke), both valves would be closed. Air from the combustion chamber can not reach the stem of the valve... nor the valve seal. (unless you have a valve not seating properly.

Run a compression check first... and then go from there.
Air escaping past the rings will be heard also coming from the airbox. Don't automatically assume that this is due to bad intake valves. Remember that your crank case breather hose is routed to the airbox.
Having the valve cover off will allow you to localize the source of the hissing. Also a good time to recheck the valve clearances. I can imagine the mechanic who did the work readjusted the clearance when he replaced the valves, but to recheck takes so little time, why not double check it.
I always check as many simple things as I can first before tearing things down.
Now then... If you still have fairly good compression, the game gets a little harder. The air leak may be too slight to detect.
Another possability along the lines of the oil light scenari: If this engine ran with low oil pressure and got hot, the head might have warped and/or blown the head gasket(another source for an oil leak.)
I've seen warped heads(usually in the mirror...)
I've seen warped heads leak oil to the outside of the engine. I've seen them vent combustion pressure to the outside of the engine.
During leakdown tests, I've had air escape from the sparkplug hole of the adjacent cylinder.
Air may hiss out of the crankcase due to a warped head or blown gasket(usually cylinders #2 or#3) while the rings are perfectly fine.
Hard to tell at this stage.
Do your tests and post the results.

[jurgenkoppen]

test results

Gentlemen,

I have the results:

Warm engine , full throttle, for compression test.
Crank breather hose off, Checking for pressure buildup at crank case breather hose nipple. TDC , compression stroke on each cylinder

Engine had run about 4 minutes, of which it had choke on for 2min, explaining probably the blackish soot

#1 Cylinder 170psi - Plug looked good- air escapes through crankcase only

#2 Cylinder 155psi - Plug looked black and greasy - air escapes through crankcase only

#3 Cylinder 162psi - Plug looked sooty with some light grey spots - air escapes through crankcase only

#4 Cylinder 165psi - Plug looked sooty over a tan base- air escapes through crankcase only

None of these airleaks were actually hissing, they were just buildup of pressure in the crankcase over say 2or 3 seconds

After those test I took off the valve cover to see if I can detect any bubbles or hissing next to the valves.
I am still trying to detect possible valve seal leakage.
So far I did not see any, I am trying to do this test by just opening an exhaust valve , for example, a little bit, and while plugging exhaust looking for air escaping around the valves.
Any better ideas, now that I have the cover off? For the intake valves?

I want to mention that the bike is quite powerful and peppy still, despite the smoke plumes.

I also checked to see if air would come out of neighboring cylinders, to get a clue about head gasket, but all is tight there. No oil leaks to the outside around the head gasket either.
What are you making of this?
Thanks, Jurgen

[prometheus578]

"Interesting..."

High compression readings, but that happens. Gauges can vary. (Usually, the readings get progressively lower... as the battery drains down from cranking)
Now then, for some basics...
And I'm not trying to insult anyone's intelligence, but everyone here has different degrees of experience, so sometimes it good to start at square one.
I consider "Choke on" for two minutes too long.
I fire it up on full choke. after about 15 seconds the RPM starts to climb. Then half choke for a little bit.. then hop on and ride.
Engines do smoke a bit when choked. ('cause of the extra fuel)
I'm glad you mentioned it was "Blue Smoke". A lot of people don't know the difference.
Blue smoke=burning oil. Black smoke= too much fuel. But again, some times it's hard to really tell.
Rereading your posts....
I "now" see that the smoke didn't start until you cleaned the carbs. ( I was gonna write "Dicked up" the carbs, but I don't know you well enough yet to tease you)
Let's assume the oil loss, or most of it, is due to external leaks and this may be a carb problem. (So far, compression and leakdown tests didn't detect anything amiss)
Plugs looking sooty can mean the engine was recently choked... or could mean that the mixture is too rich.
"Wet and greasy" describes a date I once had, but concerning plugs could mean oil fouled, but also recently having too much fuel.
I would focus now on rechecking the carbs. Check the float height, idle mixture, and make sure the choke/enrichener plungers are fully closing.
Again, not to question anyone's mental capacity, but I've seen it plenty of times... and is worth mentioning.
Bike fouls plugs, smokes and leaks out of everywhere... too much oil!
I've actually had to remind customers that the oil level is checked with the bike on the centerstand, not leaning on the sidestand.
The oil is checked with the engine off... not with it running
As T.C. astutely noted... check the petcocks and float needles, etc. A fuel leak can soon overfill an engine case with oil/fuel.
Do you have any fuel, or an oily residue dripping from the airbox?

[jurgenkoppen]

Carb issues?

Prom,
thank you for your friendly way to put across that I might have dicked the carbs.

So, does that mean, that given my test results it is clear that my rings are OK?
Could it not still be leaking valve seals?

About the carbs:
The story is that I had them out of the bike twice since I came home.
The first time was right after I arrived home. On the way back, I had to stay over night in the mountains a few time, very cold. The choke parts were clearly plugged up, causing me to nearly get stranded there. Besides, the gas milage sucked at 30mpg highway,and the plugs all looked dark. I read up a bit, in the tech section here, and decided to adjust the float level and to clear the choke passages.
The first time I did dick up the carbs by adjusting the floats to be way too lean.
It improved the gas milage alright to 38-41mpg, but had trouble starting. My plugs and the way it run told me to bring the floats back down. I must say that my Clymer manual is less than clear, to put it mildly. I had gone with the specs in the 80/81 supplement section, and ended up way too lean.
The reference drawings are not even close to what my carb floats look like. Anyway,
Out came the carbs a second time:
Float level back to nearly what they were before, but not quite as rich.
The second time I used carb cleaner, removed the choke bar to get into the top part or the chambers.
The bike now runs good and starts good, but as mentioned before, I had a plume of an actually whitish or light grey/blue smoke when I first tested it.
Since then I have some smoke when the bike is cold, and people riding behind me go "wooffy".
However, it looks like I need to read up even more on carb settings and do it again. I am starting to get real quick at pulling and installing the carbs....

About the other points:
I did fix all but one very persistent oil leaks , just by putting in the gaskets and replacing cracked covers.(shifter cover, new valve cover etc) That last one is persisting and baffling, it is at the bottom, oil pan, and I replaced the gasket in it as well. ( BTW, There was major crud and some shavings in the bottom, as well as a SMALL NUT !!, the size and shape of one of the cam shaft bearing nuts)

Finally:
I do know how to read the oil level correctly (center stand , engine off)

I do not believe that fuel is getting into the oil, my air filter chamber is dry.
But I will check again tomorrow, to see if any wetness and residue accumulated there since the last carb adjustment.
I did never once have had too much oil,I am aware of the problems that causes.
Whenever I check, and it is frequent, it is low!!!
Finally, one direct question:
If my leakdown test shows that my rings are OK and valves seal are tight, would it not follow that the oil is burned by running through leaky valve SEALS?
I have been told by riders behind me, that I get puffs at shifting.
Thanks for your patience....
Jurgen.

[Ken Talbot]

So, just to introduce another couple of ideas into the mix:

- what kind and weight of oil are you using?
I'm wondering if you might be using a light weight synthetic that might tend to work its way past selas and oil rings much more than a regular weight dino juice would

- did you set the float heights with a micrometer to within .5mm of each other?
Float height has a profound influence on the carbs, with only a mm or two making as much as 10mpg difference in fuel consumption. Running on the rich side by 2mm will give lots of black puffs every time you nail the throttle. SWMBO will tell you how much cleaner the air behind Tsunami has been since I got the floats to where they need to be.

- have the carbs been sync'd with a set of vacuum sticks?
Just curious here more than anything. If they haven't been properly sync'd, there is a slim to nil chance of it running properly. Not really a lot to do with oil consumption or black smoke, just an observation.

- have you verified the orifice in the bottom of the float bowl is clear?
This orifice is in the absolutely lowest part of the bowls, and is the most prone to blockage if there is any sort of cr@p coming out of the tank or deteriorating fuel lines. When they block, you lose fuel supply to the enrichener circuit.

[jurgenkoppen]

focus on the carb

OK guys, I get it.
The carbs will come back out.
Actually, I had been so busy being freaked out over blowing smoke, I more or less assumed it to be blue, because of the oil consumption (which may still be just loss through the persisting leak at the oilpan).
But now, reading your responses,
I now remember, that last time I cleaned the carb passages and brought the float levels back to being richer, I saw a small crack in the #3 diaphram, at the edge. I fixed it temporarily with silicone. I since have acquired another diaphragm assembly, but I must put it in.Doooh. Maybe there lies the main problem....?The silicone probably lasted from 12 till noon.
I'll be onto it today, and post some more findings today.
Any more tips on carb float settings for a '80 carb, and also pilot jet settings are welcome. The Clymer book is cryptic. I had the carbs synchronized last summer, when I had them set way to lean. But I will redo it after replacing that diaphram , I have a buddy with a mercury sticks.
I'll check the petcocks and for residue in the breather box as well. Maybe I'll get to the bottom of this, and do not need the '79 spare engine after all....
Cheers,J

[prometheus578]

Oil leak at bottom of pan....
Check the neutral switch... left side, by the shifter, sort of.
Just like some car's oil pressure sending units leak.
It's not leaking from around the threads where it screws into the engine case, but leaks "through" the unit itself... the oil coming out where the threaded portion is...where you attach the neutral light wire.

If my leakdown test shows that my rings are OK and valves seal are tight, would it not follow that the oil is burned by running through leaky valve SEALS?

Yes, I suppose this could be the case.
Seems odd that this sudden smoking evolved right after a carb repair, but then again...I t may have been doing this for a while and only recently you noticed it.
T.C. and I had an arguement, discussion, debate years ago concerning refurbishing only part of a head(Doing just the intake valves and not the exhaust... or doing the valves and not the rings) and some of the crazy things that can happen. This may be along similar lines, but would have been evident after the valve job... not just showing up now.
For a bike with so few miles on it to smoke is a little odd, but then again, the rubber parts (valve seals) are 25 years old. Then again, there's the low oil/oil light issue. The cylinder might have a bit of scoring if they were oil starved.
I'd work the carb issue to death before worrying about the valve seals. If that doesn't resolve the problem... then worry about problems with your head.
After you and a good therapist resolve that issue, pull and check the head on the bike.
There's no test for valve seals. You can't really replicate the environment that they operate in. Just replace them.
With the head off, you can then check the cylinder walls for scoring, long grooves, etc.
At 15,000 miles, I would still expect to see the original cross-hatch pattern. (I've got 50,000 miles and can still see mine)
If you can't... or the walls appear glazed, then the cylinder bank needs to be yanked for work, too.