Fuel spurting everywhere

I have recently acquired an RC24 1989 750 K and I was told it was running on 3 cylinders. The carbs were off so I have had them completely sonic cleaned and rebuilt and today I went to start the bike. It's clicked a couple of times but then it started. Fuel seemed to be leaking from somewhere so I took off the air box tried it again. The bike started again but fuel was spurting out of the crank case breather pipe (the one that attaches to the air box. I am by no means an expert but I am very confused why this should be so. Where is the fuel coming from for it to come out through here. Could a valve be stuck, could there be something wrong with the carbs? I thought I'd check on here in case it's straight forward. I don't think the bike has run properly for 5 years but it did fire and was running until I decided to stop it because of all the fuel spurting out. Any suggestions would be very helpful.

 

Sounds like one of the needle valves is not shutting off the fuel going in. Here is a trick to help you see what is going on. When working on my 83 carbs, I undo the tank mounting bolts and turn tank around 180 degrees and rest it on the tail. Put something soft on the bike to protect it, and use a tie down to keep tank from slipping. Then you can remove top cover of air box and air filter to see intakes and which carb is the culprit.

 

Could be lots of things, one thing it could have the wrong fuel pump that is pumping too much pressure and the needles can't shut it off. Could disconnect the pump and hook up a fuel bottle hanging from the roof and see if the fuel still leaks from the overflow hose

 

Fairly confident that the pump is the OEM but I will try what you say. Thank you

 

my first thought was.. why are the carbs off in the first place? did the PO fill the crank case with gas, pull the carbs then sold the bike. change the oil and filter then recheck. you may have already fixed your issue when you gave the carbs a goods talking to.

 

Very interesting thought. That didn't occur to me that they might be full already. Wouldn't the fuel eventually find its way into the sump though, over time?

 

Excess gasoline will be pulled by gravity over the piston rings, through the bearings straight into the oil sump, diluting the oil, quickly wreaking havoc all along the way. Take care of it immediately. Gasoline is an excellent solvent. Just what you DON'T want inside your engine.

 

Thank you for this. Is this likely to be terminal? What order should i do things? Obviously I'll drop the oil from the sump. Is there still likely to be any fuel still in the cylinders do you think or will it all have seeped past the pistons. Once I've done this and refilled with fresh oil should I pull the carbs and what should I look for? I had the carbs refurbed and was assured the float height was correct. If I just start the engine up with fresh oil surely it will just happen all over again. Should I put oil down the cylinders to lube the pistons. Sorry for all the questions but I suppose I just am worried that I've just got a pile of scrap metal. I should say that I stopped the bike running, it didn't stop itself.

 

The reason I suggested leaving the tank on is to have the fuel pump pressurize the bowls. I currently have a problem with a leaky gasket on one of the bowls, and it only leaks when running and fuel pump is pumping only when it is running. Hard to diagnose problems with carbs off.

I doubt very seriously that the sump has ingested very much gas, but change your oil right away. With the plugs out and carbs off crank for a minute to get fresh oil into all the bearings. Squirt a little oil in each cylinder to help the rings.

Not terminal, carbs can be tricky, just needs sorting out and patience.

 

I do not believe that an OEM pump can over-pressurize. With the carbs on and the airbox top and filter removed, you should see raw fuel bubbling up from the slide needle hole on any carb that has a leaky float needle. (While running or cranking.)

Hooking up a fuel line to carbs on the bench would reveal any float needle faults too.

 

Squirrel, this is the reason I suggested using the fuel bottle, you can work on the carbs and can see what is going on. If the carbs don't leak using the fuel bottle directly into the carbs, then you can hook the fuel bottle up to the inlet of the pump and turn the ignition on and you can see exactly what is happening. I guess there is always the chance that now the carbs have fuel in them the bits have swollen up and now might be sealing