WTF?

[jimyed]

WTF????

I rode home from a birthday dinner last night. Normal ride no hooligan stuff. The Bandit runs like a top and sits in the garage overnight doing nothing.

This morning I start up to go to work and things don’t got too well.
1.   The bike is spewing a cloud of oil smoke and misfiring .
2.   #3 carb is dripping fuel. I think from the top of the carb but couldn’t see for sure. It did this once before for a few seconds I thought it was a piece of crap the caused the float to stick I drained the float bowl then and nothing came out. Until today it had not leaked again. I drained it this morning and got a bit of brown crap out. So something is in there.
3.   Oil was dripping from the front of the valve cover.
How this is all connected I don’t know but I had to Ride the wife’s Shadow into work this morning.
So I have to fix this quick! 
Any ideas?

[Red01]

Check the valve cover vent system.  If the engine isn't breathing, this could cause pressure to build and cause oil consumption and even force oil out a weak point in the gasket.

Check the other three carbs for gas color.  Is the gas brown from oil?  This could be caused by blowback thru the carbs on decel... but I'd think that would have been disappeared soon after any accels... unless your last bit of riding before shutdown was a lot of decels.

[jimyed]

No it’s not oil in the carb. It was brown crap that came out but it was not oil. I've seen similar looking crap in dirty carbs so it's loose varnish or something from the tank. Not a lot of decels on the last (short ) ride anyway .I will check the venting though. I opened the oil filler cap to see if the gas smelled of oil at all and it may have had some pressure so that is a possibility.

After thinking I think there’s no real connection between the oil and gas just a stupid coincidence. 

I have not taken the carbs off yet this is my excuse. Family Sick day tomorrow I would guess!

[Red01]

I was kind of leaning toward them being separate events, but thought if the brown was oil, it was a remote possibility.

Just out of curiosity, is the oil leak coming from the main gasket, or thru the spark plug tower drains?

[jimyed]

Hard to say for sure I was already late for work and didn't have time to really lok but I think it may be the Plug drain.

Worst part is i just got handed 4 days work to have done by end of day Wednesday. No Sick days possible dammit! Well I'll be up late tonight i bet!

[jimyed]

Ok here's where it stands.

The carbs are not leaking now. I thought it was #3 but it may have been another. It was leaking fuel from the vent tube between #3 and #4 . I drained all carbs but #1 (Screw is tight and started to strip. STUPID PHILIPS HEADS!!!!!!!!!) I’ll have to wait until the carbs are pulled prior to getting that one loose. Nothing really came out but gas. It was still leaking so I blew some air into the vent tube and it stopped leaking. . I hope that whatever is causing the overflowing is gone but that’s a faint hope  to be honest.

I rode it to work and there’s no oil smoke and once warmed it ran OK if not a good as usual. It has a pulsing sort of hesitation that I had put down to it being a little lean but now think may be dirty carbs.

In summery I did the following.

Drained carbs 2-4 several times.
Tapped all 4 float bowls a few times each.
Blew air into both vent tubes to try to clear any obstructions.
Cleaned the air filter as best as possible ( Due for a change)
Changed the oil and filter to make sure I had no fuel contamination in the Oil.
Put some seafoam in the tank to see if it can help at all.

I did not look at the plugs for no good reason I can think of I meant to do that but forgot and ran out of time. I plan on looking at #1 and 4 at lunch  to see what they are doing anyway. 

I plan to jet over the winter but may have to pull the carbs sooner than that to clean them. I HATE missing riding time but if it’s not running well I won’t enjoy anyway I guess. 

[pmackie]

Yup...It sounds like you have a carb overfilling due to crud in the needle valve. The smoke you are seeing is likely black smoke from too much fuel not blue smoke from buring oil.

2ndly, you may be builing up a little crankcase pressure, which will push a little oil out somewhere.

I would start with:

1. Remove and clean the carbs. Maybe drain the fuel tank as well. Add a in-line filter if you don't have one.
2. Make sure the airbox is drained of any oil. There is a plugged hose beside the right footpeg. Also, look into the airbox with a flashlight, with the filter removed, and see if any oil has accumulated.
3. Check all of your crankcase vent hoses and see if any are pinched or plugged. There is one off the top of the head and one off the crankcase. Make sure they are routed so that they don't get pinched.

[jimyed]

Another twist . the pair pipe on Cyl.#4 that i had capped after removing the pair valve broke off and now it sounds like a tractor.  it's not been a good week.

[jimyed]

While looking the bike  over again last night I tried to rearrange the plug wires to make sure they were not causing a misfire. #4 cyl 's plug wire pulled out of the boot with no effort. A close look revealed that the rubber was rock hard and the wire looked burnt. I striped the rubber back  1/8 of an inch and trimmed the wire back as well I then reinserted the wire into the boot and was able to get a better connection. I also taped the wire to the boot.

The bike runs FAR stronger than it has in weeks.  I missed the loose wire  completely . All the other wires seem OK after I carefully checked them.

I still think there is a carb issue but I will try to hold on until the cold weather before tearing everything apart.

[jimyed]

So Thursday it overflowed AGAIN and I couldn’t clear it by draining and tapping so the carbs finally came off Saturday. There was nothing in any float bowl but #2 which had a little black crap. I carefully inspected everything but found no blockages I also cleaned the carbs. .Once reassembled  I tried to overflow the carbs on the bench but they were fine. Once back on the bike they were actually WORSE. Gas is pouring out of the vent between Carb 3 and 4. 

I have added an inline filter. Drilled out my idle mixture screws. Ordered a new air filter . I did not set the float height as it looked OK but I’ll do that when the carbs come back off. (BTW anybody have any tricks to make taking throttle cables off and on a little easier?)

I have done all the suggestion s so far (Thanks everybody) anyone got anything else?

[Mongo]

Replace the petcock!

[jimyed]

Replace the petcock!

No it overflows with the tank or my auxilery fuel tank . i'll think about changing though if i can't find something else

[Mongo]

Replace the petcock!

No it overflows with the tank or my auxilery fuel tank . i'll think about changing though if i can't find something else

I just replaced mine for the second time the first swap was a used one I picked up on Flea Bay the new one has different part number so I suspect there was an issue with the original factory unit!

I was riding home from work a few weeks ago when I noticed my bike was smoking when I threw a rev. Got home and started checking things out and my sight glass indicated it was over full sure as shit it was gas. Being as I had been through this before I replaced the petcock changed the oil and the problem went away! Something to do with the vacuum diaphragm going south and allowing gas to flood the carbs!

[jimyed]

Ok Finally I have a resolution.

I pulled the carbs again (The cables! dam the cables what a PITA) and carefully cleaned them again. I found a piece of what looked like lint in #4's needle seat that I had missed the first time I took them apart. I also drained the gas tank and added an inline fuel filter. No more overflowing carbs now.

I took the opportunity to drill out the idle mixture screw caps and adjusted the mixture . When I checked the screws #1 was 1 ¼ turns out #2 was 1/8th  of a turn out and #3 and #4 were 1 2/3 of a turn out. I turned all out to 2 ½ and the bike is way more responsive and much smoother.   

I also had a new chain and sprockets installed this afternoon and I found out that some (Most?) of the weird surging was my failed chain and rear sprocket. Not the carbs as I once thought.

So the Bandit is back to running like a top and I am so HAPPY in fact it is better than when I bought it . No doubt that’s the mixture screws. 

[Red01]

COOL!