Fuel leak from pipe on cylinder head cover

[Buddybear1996]

Hi im new to the site and looking for some help.
I recently bought a 1988 nc23. When i got it it was going. It just needed a few small things and a paintjob. I got the majority of the parts and got it serviced.
My mechanic told me i needed a fuel tap as it had a small leak and it had to be left on always. The leak was very minor. If you left it sitting for a few hours you woundt see a puddle under it maybe a drop or 2.

The first day i had it out it was driving fine. I done about 40km on it. Just before i took it home i stopped at a shop and when i tried to start it it turned over a few times but then made a clunk sound and stopped turning. I tried it a few times and it wouldnt turn but after 3 or 4 times it started turning again and fired up. (I dont know if this is revelavent to the next problem)

The next morning when i went out it made the clunk noise but started then. I let it warm up and when i pushed it out of the garage i saw a big puddle of fuel. I switched it off and when i checked it didnt look like it came from the fuel tap. I started it up again to see where the fuel was coming from. After approx 5 seconds of starting i saw fuel gushing out from a small pipe on the cylinder head cover. It was coming from the aluminium cover shown in the link below. In between the 2 middle spark plugs at the top. Where the number 1 is. There was about 3/4 of a tank of petrol in it and after it was nearly empty.

http://images.cmsnl.com/img/partslists/ ... 1_395f.jpg

When i went out this morning i noticed in the puddle there was no petrol but a considerable amount of oil left.

Thanks in advance for your help
Buddybear

[Buddybear1996]

I dont know if you can view the url.

If you google nc23 cylinder head cover its the third image. Its on cmsnl website.

[Davez29]

I'm no expert but if I had fuel coming out of anywhere its not supposed to I would not attempt to start the bike. I would first remove the tank and either replace or fix the tap, depending on the leak it may be just The o ring gone. Next to check would be pipes and pump for leaks. Make sure the pump is plumbed in correctly. Next in line would be the carbs, overhaul these and make sure the floats are not sticking open allowing fuel into the engine. Once your sure they are working correctly perhaps change the oil to be sure of no contamination that might make your engine go bang!

I'm sure others could offer better advice at what's coming out of your engine breather. I can't see how fuel would get in there unless your engine is completely flooded with fuel, surely not if you are starting it? I don't know to be honest.

[dobbslc]

A combination of permanently on fuel tap and a leaking carb float or floats will fill the engine up with petrol. The clunk could be the engine hydrolocking ie it can't compress the liquid fuel and it's locking solid. If you keep going it will either bend a con rodn in the engine or catch fire.
Get it sorted out asap.

[Davez29]

Yes my thoughts are as dobbslc has said, I couldn't think of the word hydro lock, but your symptoms sounded like that to me. As an aside, a friend got this fuel in her engine on her Kawasaki 305 while going down a motorway, it turbocharged the bike for a uncontrollable second then promptly blew a hole in the engine, luckily she survived. Get it sorted

[Gimly56]

Sounds serious to be honest? If you have oil and fuel mixing then you have a considerable mechanical fail somewhere.

I had a 'clunk' on my NC23 similar to what you are describing and it turned out it a small piece of metal which served only to hold a few wires in place near the flywheel had come loose and was 'clunking' on the flywheel when the engine turned over. Was an easy fix.

But yeah in regards to the fuel spilling out of your breather hose above your engine cover.....if you can afford it, pull the engine apart and have a decent inspection...before it goes 'BOOM!'

[Buddybear1996]

Yeah u got it spot on dobbslc.
I took it 2 a mechanic and he said the floats were sticking causing the carbs to fill then overflow into the cylinders and then out the little pipe at the top. He said i could have bent a con rod from trying to turn it over when the cylinder was full of fuel. He cleaned the carbs. Changed the oil and filter. Going the best now.
Thanks 4 the help

[Gimly56]

Wow that's cool to know. Never heard of an NC23 hydro-locking before....have now!!