Fuel leak

Message

Oddkid · #1 Post by **Oddkid** » Tue Jan 11, 2011 6:51 pm

Hey i've found a bit of a problem.

Basically, for no reason i can fathom, my tank has sprung a leak. Petrol is dripping off the left hand side of the bike while its on its stand. Further investigation suggests fuel coming from a blue breather pipe marked cannister use only.

Alternatively it may be coming from the bottom of the fuel pump though we can't see where.

What does the pipe marked cannister use only do?

Otherwise, help?

Oddkid · #2 Post by **Oddkid** » Wed Jan 12, 2011 1:34 pm

Griff has suggested a warped tank and reckons i should warm it with a hairdryer and bend it back into shape.

D-Rider · #3 Post by **D-Rider** » Wed Jan 12, 2011 2:19 pm

Oddkid wrote:Griff has suggested a warped tank and reckons i should warm it with a hairdryer and bend it back into shape.

Well - has that helped?

Also, have you followed up on the ideas I PMd you (on Cov Bikers)?

Well I wouldn't say that there are any common faults but I have heard of the occasional problem.
It has been known for the seal at the base of the fuel pump to fail.
PM Aladinsaneuk on Ridersite as I know he had some problem here and had to level the surface on his Falco's tank to get it to seal well. Mille and Falco won't be that different.
Obviously check you don't have any cracks in your fuel lines.
Another thing known to fail is the plastic quick connector in the fuel return line. I think that Futuras and Caponords had the worst of this but it's still not the best design on the Falco and Mille.
Over on the AF1 forum they sourced a metal quick connector that some have fitted.

These are the places I'd start looking.

Oddkid · #4 Post by **Oddkid** » Wed Jan 12, 2011 2:27 pm

No i didn't pm anyone in the end. Evoboy came round and took the tank off to have a l ook. We were pretty sure we were losing fuel from the overflow pipe but now i think its more likely we're losing it from the seal from the pump. Griff says its not uncommon for this to happen with the changing temperatures.

Eithrway, the pump has to come off, so if its just the gasket it'll be a pleasant surprise and easy fix, i'd rather not have to remould my tank if i can help it.

Oddkid · #5 Post by **Oddkid** » Thu Jan 13, 2011 12:10 pm

Alex is going to give me a hand getting hte tank off again and we'll do a leak test. My only worry is once its off will it go back on because of theh copper washers in the banjo bolts. I won't know till i take it off.

Aladinsaneuk · #6 Post by **Aladinsaneuk** » Thu Jan 13, 2011 1:14 pm

https://www.ridersite.com/viewtopic.ph ... +pump+seal

Oddkid · #7 Post by **Oddkid** » Thu Jan 13, 2011 1:17 pm

Alex is on his way over right now. We're going to give it a go and find out. My leak is more than every 30 seconds or so, i lost a whole tank over a couple of days. Really hoping form some good news!

Aladinsaneuk · #8 Post by **Aladinsaneuk** » Thu Jan 13, 2011 3:18 pm

I would suspect that bottom fuel pump seal.... and the gasket compund mentioned in the above link is good with petrol :)

Oddkid · #9 Post by **Oddkid** » Thu Jan 13, 2011 3:42 pm

Ok, we're just waiting for the instant gasket stuff to set, we leaned the original gasket and the surface of the tank and we've stuck it all back together.

I'll keep you informed.

Willopotomas · #10 Post by **Willopotomas** » Thu Jan 13, 2011 8:13 pm

Instant gasket will be a short term bodge. Unless you buy the oober expensive stuff that goes off in petrol. If it works, i'll give it a fortnight before it starts leaking again..

The good thing about copper washers is they can be used again and again. Just anneal them. Heat them up to cherry red all over then quench in cold water. Be nice n' soft ready to use.

Oddkid · #11 Post by **Oddkid** » Thu Jan 13, 2011 8:50 pm

The instand gasket is just reinforcing the original gasket so it should be ok. If it does strt leaking again then its because the tank is warped.

D-Rider · #12 Post by **D-Rider** » Thu Jan 13, 2011 9:00 pm

Oddkid wrote:The instand gasket is just reinforcing the original gasket

If the original gasket is OK it doesn't need "reinforcing".
If you're using instant gasket to cope with imperfections in the gasket you are relying on the instant gasket to seal.

Have you just tried to re-use an old, compressed gasket that you suspected was leaking in the first place rather than check the mounting surfaces and replace the gasket ?

Aladinsaneuk · #13 Post by **Aladinsaneuk** » Thu Jan 13, 2011 10:16 pm

With respect chaps

Having repaired my own falco tank / pump seal ....

The rubber gasket is not great - the recess it sits in means that it is not too proud - so a good seal can be hard to achieve

I fixed mine by cleaning the recess VERY well using an air line
I then used the PETROL resistant gasket as a thin bead in the recess to raise the profile of the rubber gasket so helping a seal

A none petrol resistant sealant will fail very quickly

Oh - the bolts do need to be torqued correctly!

Oddkid · #14 Post by **Oddkid** » Thu Jan 13, 2011 10:24 pm

We thought hte recess was pretty deep compared to the seal. I think there was just a lot of grime and gaff in it but overall the seal was in really good condition. We thought it'd be best to put the instant gasket (petrol and oil resistant)in aswell for the extra security after we washed the recess out with a jay cloth and a bit of petrol. It hasn't leaked so far.

D-Rider · #15 Post by **D-Rider** » Thu Jan 13, 2011 10:26 pm

Ah fair enough - I hadn't factored in the Jay-cloth