Engine smoke

[tomatao]

Seafoam did the trick. I added some to the cylinders last night and let it sit until this evening. I let it run for about 20 minutes and the smoke cleared up, almost. I'm sure with a little more time to run it will clear up.

[saddle up]

Don't know about seafoam, but have used in the past the old Marvel mysterey Oil. It'll break them rings lose.
Good luck

[AustinPhoenix]

Newbie!!

I FINALLY got my 80 xs11g to start last night and today but have some questions for you gurus.

Things I did:
Changed spark plugs (old ones were super crusty and over gapped. New ones gapped between .028 and .03)
Added a little oil to get it up to the right point in the glass (engine was cold when added)
Cleaned the float bowls of the carbs, but couldn't get 2 or 3 covers off to pull the diaphragm. Carb 1 dribbles gas, but the petcock on that side seems to leak.
Added inline fuel filters
Compression test (110, 95, 115,115---then added half a teaspoon of oil to number 2 cylinder and brought it up to 115)

When I started it, full enricher, it cranked and purred right away. About 2 minutes later she just died and wouldn't start again. She just cranked.

Today, I checked all the plugs and tried again. Nothing. So I took the enricher off thinking that I might have flooded the engine, opened the throttle fully, and cranked. She started right up. Then a minute later, died. Wouldn't start up with the throttle. Went back to the enricher and opened it full. Vroom....2 minutes dead and wouldn't turn over. Went back to the throttle...start up. etc for another round or two.

I noticed on the last run, white smoke was coming out of cylinder 3 and 4 exhaust manifolds. I killed the engine. Watched the smoke and curiosity. Then lightly touched the manifolds to see if they were all firing...sure were.

Pulled the 3 &4 plugs, both cylinders were full of white smoke.

So here are my questions after reading the thread: since engines smoke a little after they've been sitting for a while (mine was sitting for 9-10 months without prep)...why would only 2 of my cylinders smoke? Could it have anything to do with the mixture or flow coming from the other petcock into 3 &4 carbs?

My plan: Rebuild both petcocks...figured why do one and not the other. Check the float bowl and find out whats going on with the overflow. And add some Seafoam to the gas, oil and spray some through the carbs after the seafoam has been sitting in the engine for a day.

Any suggestions, tips, warnings? Anything and everything helps!

Thanks XSives!!

[TopCatGr58]

Hey Jason,

The petcocks leaking isn't as much of a concern as the carbs leaking! Fix the carbs first. Most likely the viton tipped float needle valves may have grooves worn in them, or just crud sticking between them and the valve seat. Inline fuel filters are a must!...Oh, just saw you did ADD them. White smoke is usually fuel, too much!

Now, with your bike being a standard, your petcocks are vacuum controlled. With it cutting off every 2 minutes, sounds like the petcocks are not maintaining adequate flow to keep the float bowls full, you're running out of fuel. Once you spend the time to switch to choke, etc, the leaking petcocks can dribble enough fuel into the bowls to allow starting again! TRY putting the petcocks on PRIME and see if it will stay running longer than 2 minutes. ALSO make sure you have a FAN blowing at the engine if you are going to be idling/running it standing still for more than 5 minutes to prevent overheating!

IF the petock vacuum valve is leaking/ripped, it can allow fuel to flow into the engine thru the vacuum line going to the synch port on the intake boots!

As has been suggested, some MMO or SeaFoam into the cylinder with the low compression may help to unstick the rings...IF they are stuck. But it may also be some fine rust that has gotten into the cylinder, so just running the bike ON THE ROAD for 50-100 miles may just allow the rings to reseat and scrub the fine rust off and you will get your compression back!?

Did you drain the gas tank before trying to put it back into service. Perhaps some water collected in it, settled to the bottom and has gotten into the fuel/ carbs!?!?

Also, can't remember if you pulled the carbs and cleaned them, including the pilot circuit, jets, screws, etc?
T.C.

[dbeardslee]

Careful with that seafoam in the oil. I did it and prior had no oil leaks from the head gasket. It DID clean the engine, but I think the gunk was sealing the head gasket, 'cause after I did it I got a BIG oil leak. Just an FYI.

[skids]

How long did ypu run the engine with the seafoam in the crankcase and how much did you use?

Originally posted by dbeardslee
'cause after I did it I got a BIG oil leak. Just an FYI.

[wa407mpp]

I used to have a bike that if you let it set for 2 weeks, then started it , it would smoke, but if you let it warm up then cool down it wouldn't smoke again until you lent it set for 2 weeks again. I think it had a little wear in the valve seals which let it build up oil in the cylinders if it set long enough, but not if you ran it frequently. I also remember reading in one of the original magazine articles that smoking was common with bikes even when they were new and it was a rare one that didn't smoke a little.

[dbeardslee]

Skids - I put about a third of a bottle in and ran it about 200 miles. It was making the clutch slip too so I drained it and replaced with 20-50 dino. The clutch straightened out, but my head gasket had a big groove in it back by the cam chain tunnel, and I'm assuming it had some crud in the groove, cause it wasn't leaking there before. If your going to put that stuff in the crankcase I don't think you want to leave it there very long before changing the oil and filter.

[TopCatGr58]

Hey Dbeardslee,

I hope it wasn't someone on here that told you to put the Seafoam in the oil and then DRIVE it??

We've tried to be careful to state that you don't want to put any real LOAD on the engine with either MMO or Seafoam in the oil, just idling enough to get to temp and to get to circulate throughout the engine to get at all of the gum/varnish buildup! Then immediately drain and replace with oil/filter.

It thins the oil quite a bit, like gasoline and could damage bearings and such!??
T.C.

[bigb9582]

Originally posted by wa407mpp
I used to have a bike that if you let it set for 2 weeks, then started it , it would smoke, but if you let it warm up then cool down it wouldn't smoke again until you lent it set for 2 weeks again. I think it had a little wear in the valve seals which let it build up oil in the cylinders if it set long enough, but not if you ran it frequently. I also remember reading in one of the original magazine articles that smoking was common with bikes even when they were new and it was a rare one that didn't smoke a little.

my bike does that. let it sit for a while, it will smoke on startup then be fine.
but ride it everyday, no smoke.

[AustinPhoenix]

Seafoam, petcocks and smoke oh my!

TC,

The leaking stopped today after gently, but firmly smacking the bowl with a screw driver handle. I'm thinking the float got hung up on something or something equally simple.

The petcocks are going to get rebuilt. My left one drips slowly but certainly. My right one barely dribbles anything out even on prime. It's just slow...certainly not stopped up completely.

I'm still concerned about cylinders 3&4 smoking.

She starts then immediately dies with the enricher at full. Then immediately close the enricher, full throttle, push start, and away she goes. I, of course, don't leave the throttle open fully, but immediately drop it to keep the engine around 1k rpm. I kept it at this for about 3 min, then killed it. Tried to start her up again with the throttle...nothing. Back to enricher...back to throttle and she starts. Maybe my bike is just...finicky.

[dbeardslee]

TC - I was just following the label directions when I did it and have since seen posts that mention not leaving it in long. The label just tells you to put it in the crankcase. Your right on the money about it thinning the oil. When I drained it it was really watery. I don't think it did any damage, it just really cleans things. Have since rebuilt the head and replaced the gasket and have run it a couple hundred miles with no leaks. I had the same thought about other things that might have been affected so I've been parking it on a clean piece of cardboard. Nothing on the cardboard, nothing on the bike, and it's running great.

I have received nothing but good advice from this site. You guys are great, and I couldn't have gotten my bike on the road without your help.

[Ken Talbot]

Re: Newbie!!

Originally posted by AustinPhoenix
Cleaned the float bowls of the carbs, but couldn't get 2 or 3 covers off to pull the diaphragm.

So, you have not had all four carbs completely stripped down for a thorough cleaning. This means you have only completed cleaning #1 of your first triple clean. Before you waste any more time looking at petcocks and various other scenarios, pull the carbs again, strip them down completely, and clean them properly. Until this is done, and done without any shortcuts, you are just going around in circles.

Don't mean to sound harsh, but fully clean carbs is your starting point. Trust me....

[AustinPhoenix]

Carbs

Ken,

I completely agree with you. I'm either going to just wait another day or two for my buddy to finish with my dremel so I can cut the two screws off that are completely stuck, or I have to buy an impact driver to break them out. Whoever worked on the bike before I bought it, super tightened EVERY bolt.

In the mean time, I'm just doing stuff to pass the time. (ie. stripping all the electrical stuff out to wipe it clean or rewrap it) This is quickly becoming an obsession.

[wa407mpp]

tight bolts.

Those bolts probably weren't over tightened, when you use fasteners of different metal then the parts their holding, you get a chemical reaction between the two metals and they bond to each other. you can prevent this from happening by using a good anti-seize lubricant, just don't use it on brake bolts or lug bolts or anything else you don't want to work loose.