Carburetor Issues??

[Bumblebee]

but when this thing started it literaly drained the whole tank of gas.

As in just sucked fuel out of the gas tank very quickly then you have gas in the crankcase and no mess on the ground or in the air box? That is so not right. There's no way a properly plumbed and operating engine like this can pull large quantities of gas from the tank directly into the crankcase.

It sounds like there is something seriously messed up.
For starters, after the oil change, I think you need to go through your shop manual and chase all the plumbing. Account for every hose. Find out what is connected to what and where it's all supposed to be.

[Munkey]

whats the tube that connects from the head to the crankcase???

I may be wrong here but I think the one on the head should go the airbox. 

You got something really weird going on and I agree with Bee, it seems to be in some mismatched plumbing. 

[Munkey]

Is there fuel in your airbox?

Could it be that the stuck float, or most likely floats, is causing fuel to overflow the carb and backup into the airbox and down the breather tube connected to the crankcase?

[Garo]

wow. COMPLETELY full of gas.  this was not like this before.  I did check the oil before and there was no gas in it.  well, at least I got a engine flush...HAHA...?  Thank you for the help guys.

[Bumblebee]

wow. COMPLETELY full of gas.  this was not like this before.  I did check the oil before and there was no gas in it.  well, at least I got a engine flush...HAHA...?  Thank you for the help guys.

That is seriously messed up bigtime.

The good thing is that you didn't hydraulic lock the crankcase...or at least I hope you didn't.


My suggestion:
Pull the drain plug and drain the oil.
Pull the oil filter off and dump the gas out of it also.

Then it's time to follow all the plumbing and I mean all of it and find out why and how the gas tank is attached to the crankcase. Don't stop until you find the cause and can clearly identify it. Then continue the plumbing verification process until you are completely finished to insure everything else is connected properly.

Once you find the problem and fix it, then start cleaning up the engine.
Drain the airbox even if it looks dry. There's usually a capped hose under the bike that goes to a reservior and continues up into the airbox.
Get ALL the gasoline out of the engine. That means out of the lower crankshaft areas, the transmission and clutch areas. Note that on some engines, there are secondary plugs on the engine that can drain oil out of areas such as the crankshaft galleries.
Gasoline is almost certainly in the rocker galleries above the pistons and that has to be cleaned out also.
Personally I would pull the clutch cover, starter, any other covers or parts that access the core engine and any other drains on the engine case then leave it fully open for a day or two with a fan blowing on it. Nothing wrong with blowing it out with a shop vac or compressed air either.

Once it is all cleaned out, install a new oil filter, load the engine with new oil then spin the starter a few times then start it. Verify you are not getting fuel into the crankcase and watch it closely for a while. After maybe 10 minutes, I would drain the oil and refill with new oil again. (the first oil change is just to flush the majority of the remaining fuel residue out of the engine) Once you have no fuel contamination in the oil, ride 100 miles while watching it closely then do another oil/filter change.


If it was me, I would be debating on whether to go visit whoever replumbed the engine with my 1-5/16" combination wrench for a little discussion out behind the barn with no witnesses or the drain pan full of oil/gasoline to dump over their head. Maybe both.

[Brittles]

If I had to guess, I'd say your petcock is not working as it should....... allowing fuel to gravity feed into the carbs and flooding everything.

Get that, and any stuck carb floats fixed. and you'll be golden.

[Bumblebee]

If I had to guess, I'd say your petcock is not working as it should....... allowing fuel to gravity feed into the carbs and flooding everything.

Get that, and any stuck carb floats fixed. and you'll be golden.

There's no direct pathway between the fuel tank and into the crankcase. Piston rings and valve guides simply don't leak that much even if fully flooded. The only possible route assuming no plumbing shennagians is through the air box and that won't get gallons of fuel.

It'll be interesting to find out exactly how the fuel is finding its way into inaccessable areas of the engine.

[skramer360]

We work on small engines where I work (lawn mowers, tractors, etc.) We frequently see gasoline filled crankcases on tractors where the float is not working in the carb. The gasoline is much thinner than oil and will easily leak past the rings into the crankcase. Just my $.02.

[Brittles]

There's no direct pathway between the fuel tank and into the crankcase. Piston rings and valve guides simply don't leak that much even if fully flooded. The only possible route assuming no plumbing shennagians is through the air box and that won't get gallons of fuel.

I'm not sure exactly how the gas gets into the crankcase, but I've had it happen twice and in both cases it was the petcock. First time was on an old Yamaha that had a petcock with a "prime" setting on it. This setting lets fuel gravity feed to fill the float bowls, but I didn't know that at the time and left it in that position....................result was gas in the crankcase (that's why they stopped making petcocks like that from what I understand). The other time was on my current CB700...........faulty petcock was free flowing and the result was gas in the crankcase. Fixed the petcock and that fixed the problem.

[Garo]

insane.  amazing how much gas flowed into the crankcase.  I know the petcock is not in the best shape because I had to take it apart and clean it to get it to work before.  Plus I left it in the on position the whole time its been parked.  so I will definitely order a new petcock.  like I said when I dropped the float bowls one was stuck down.  fixed that.  I drained all the oil/gas out and will continue tomorrow.  haha leave it to my luck to get something as nuts as this.  once again you guys are great and Bumblebee I would definetly like to see some vids of your bike. 

[niteman]

Holy crap! Have you found the reason behind this yet?