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Discussion Starter · #1 ·
So after I installed my new TOC manual cam chain tensioners, I was testing the adjustments by listening with a stethoscope while revving the engine, but I didn't keep an eye on the tach. I mistakenly overrevved the engine, and sprayed the inside of my surge box with oil through the crankcase vents. What a mess.

Before noticing the problem, I test rode it and it ran OK. The next day it would start then die as soon as I cracked the throttle. Oil was seeping around the carb boots and dripping from the surge box drain. I pulled the boots off the box and cleaned out the boots and as much of the box as I could and sprayed the carbs with cleaner, but it still dies as soon as I try to wind it up.

I'm hoping I can get the oil cleaned out without having to pull the carbs.

Has anyone run into this problem? Suggestions?
 

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So after I installed my new TOC manual cam chain tensioners, I was testing the adjustments by listening with a stethoscope while revving the engine, but I didn't keep an eye on the tach. I mistakenly overrevved the engine, and sprayed the inside of my surge box with oil through the crankcase vents. What a mess.

Before noticing the problem, I test rode it and it ran OK. The next day it would start then die as soon as I cracked the throttle. Oil was seeping around the carb boots and dripping from the surge box drain. I pulled the boots off the box and cleaned out the boots and as much of the box as I could and sprayed the carbs with cleaner, but it still dies as soon as I try to wind it up.

I'm hoping I can get the oil cleaned out without having to pull the carbs.

Has anyone run into this problem? Suggestions?
Sounds like there's excessive crankcase pressure, which could mean a damaged piston or rings.

High RPM alone shouldn't cause the pressure.

Is the crankcase vent blocked?
 

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I didn’t use a stethoscope when I installed my MCCTs, just my ear. I did over-tighten at first but that just caused me to stall the motor when it fully warmed up. What you described sounds like when I left the petcock open while in storage. The fuel leaked over time and filled the crankcase so the first ride after taking it out caused oil to make its way out from anywhere it could.
So I’m not sure what “over revving” would do while installing MCCTs other than make more noise if too loose or make a weird whirring noise if too tight.
 

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Discussion Starter · #4 ·
I don't think the vents are blocked, but how would I check?

It wouldn't surprise me of there is some ring/cylinder damage. I'm the 3rd owner, and don't really have any history on the bike, other than it had 18.5k on it and needed a stator swap when I bought it, and about 20k now.
 

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I don't think the vents are blocked, but how would I check?

It wouldn't surprise me of there is some ring/cylinder damage. I'm the 3rd owner, and don't really have any history on the bike, other than it had 18.5k on it and needed a stator swap when I bought it, and about 20k now.
At the front of the engine above the oil filter there should be a hose that has a 90 degree bend upward and it plugs into the airbox.

Just make sure it's not plugged some way. But thinking more about it... The vent must be open if that's actually oil you were seeing.

Could it have been gas? As mmart said... The gas can get dirty from the airbox. They are known to collect a lot of gas if one of the carbs overflows, there's no overflow hose on these carbs.

You can pull that crankcase vent hose off the engine then rev it up and watch to see if a lot of air and oil comes out. Some smoky vapor will be normal, but it shouldn't be blowing out hard at all.

Also make sure the oil isn't overfull. That can happen if gas overflows and fills up the crankcase. Gas in the oil.
 

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Discussion Starter · #6 ·
Smells/looks like I got gas in my oil. I did an oil change recently, but now the level is well over the "full" mark, and the oil smells like it has gas in it.

My petcock is not leaking gas into the vacuum line, though.

Stuck float valve in one or both carbs? Could this happen if oil got into the air intakes?

Do I need to pull/clean/rebuild the carbs?

What's the easiest way to pull the carbs?
 

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It's probably why you had oil in the intakes. Have the carbs beencleaned and rebuilt before?. There are several write ups for pulling the carbs After I did the ear shaves I pretty much forgot how much work pulling them with the stock air cleaners was. Did you do the "backblow" to the carbs ever?
 

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It's the front cylinder carb most often, as far as a sticking float and overflowing into the front cylinder. That carb more than likely dries up first if it's parked on the side stand.


It was full to the gills, gushed thinned oily gas up into the airbox via the crankcase vent and it ran out to the filters.

Is it me or did this new thread just merge into the old one?
 

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Sometimes, carefully tapping on the sides of the carbs can free a stuck float, if the carbs aren't dirty it should be fine once you get the float moving.

Backblow can work if there's no dirt floating in there.

Otherwise, inspect and clean, check float valve and seat, make sure the float has no gas in it.
 

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Discussion Starter · #10 ·
I've never touched the carbs, other than spraying carb cleaner into the air intakes while trying to clean up after the oil mess. I have no idea what any PO might have done to them. They look very stock, so I don't think anyone has done anything to them.

No idea what "backblow" is.

Sounds like I'm gonna have to pull them after all sigh
 

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Discussion Starter · #13 ·
Well, that didn't do the trick.

I tried the backblow, and even got a suction gun and worked some seafoam back and forth through the carbs.

It's better, but still not running right. Still seems like I'm still flooding the front cylinder.

Would the overfull oil (with the gas in it) be preventing it from running right, or do I really need a carb rebuild?
 

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Well, that didn't do the trick.

I tried the backblow, and even got a suction gun and worked some seafoam back and forth through the carbs.

It's better, but still not running right. Still seems like I'm still flooding the front cylinder.

Would the overfull oil (with the gas in it) be preventing it from running right, or do I really need a carb rebuild?
Absolutely, the oily gas can pass upward through the rings and end up in the cylinder just like it came through the carb. Though I will be surprised if that's happening on this engine. If the valve guides leak much, more fuel can make it through there (in the oil).

I've seen it happen on a V8 with the mechanical fuel pump leaking into the crankcase. I was all over the carb trying to find out why it was flooding and blowing black smoke. It was the fuel pump.

I happened to pull the dipstick out and it had white vapor rolling off of it and the oil was at least a gallon overfull. It shot across the garage when I pulled the drain plug.
 

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If air bleeds are plugged, it can cause gas to siphon out of the bowl into the intake, even with the engine not running. That's why it's important to clean the carb body.

The holes with the BB stuck in them, are air bleeds. They're on the sides of the body and at the intake where the air duct clamps on.

You don't remove them, just spray them hard and use air to blow the dirt out.

On some of the old dirt bikes you could cover an air bleed with your finger and gas would run out the overflow. The Vulcan carbs don't have overflow hoses.

Could be a shred of rubber off of a fuel hose, holding the float valve open. Have to bite the bullet and douche them out.
 

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I'm anal about doing everything I can to keep junk out of the carbs. To assist in that effort, I installed a see-through fuel filter on each of the lines going to the carbs.
 

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I'm religious about getting seafoam in the tank for storage.

I haven't ridden for about three years, the same gas has been in the tank all that time. It started right up the other day, well after four pushes of the button to get the gas flowing.

Ten year old AGM battery, still sits at 13.1v .
 
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