406 cc greeves engined Enfield

[Cockney Bob]

My bike having gone the last 100 miles with no problems nothing fallen off etc.Going well with new air filter on it.
Then today on the way to the parking demo decided it would no longer idle.It can run slow but will not idle.I tried adjusting the Throttle cable but still no go.Then I noticed Diesel dripping from the base of the engine.No leaks in the pipes no leaks in the tank so far as I can tell no leaks in the pump etc but Diesel there is slowly dripping from the bottom of the engine.It is not in the oil as the level has not risen .Any Ideas from the team.
Bob

[coachgeo]

in the us the auto part stores now sell a chemical you can add to liquid (one each for lube, coolant, fuel etc.) that glows under a special black light. Might even be a generic black light. Anywayyyy.. with this stuff it makes it easier to trace leaks.

You might try and see if that stuff is over there too. If so try that. Add as recommended to your fuel tank..... run her at night while watching with the black light.

[Cockney Bob]

seems a bit extreme adding glowing chemicals.I doubt it would do any good.
If I turn off the tank the leak stops so that takes out the tank.The pipes do not leak it seems to be coming from the front of the engine near the decompressor for stopping.Is there a fuel feed in there.

[coachgeo]

do these IP's put a vacuum on the fuel lines like an automtive diesel? Do they have a fuel pump anywhere that pressurizes any part of the system? Obviously there is a a portion that is slightly pressurized (gravity feed), speaking of something more than that though besides the injection side of the system.

if so this will help you locate leak.

Leak could then be when there is NO VACUUME if such a situation exist besides engine off

When engine is running if it is still actually leaking fuel it could then be in the part fuel is pressureized.

The poor running engine could be coming from it sucking in air though.

Reason I suggested the tracer chemicals is often the leak is actually far from where you see the results. The wet area is just the place the physics allows it to collect. Tracer chemical lets you see the whole trail back to the source of the leak

Could it be an injector line? That would also explain poor running.

[Cockney Bob]

It is not actually running poorly just wont Idle it runs fine up to maximum speed but wont tick over .If i hold the throttle open it will run slowly .
This happened suddenly at the end of a short run I wondered if it was the decompresor in the front letting in air.
The diesel seems to come from the front then run to the back of the engine.
No in line compressor just the pump and fuel injector which seem OK.

[Cockney Bob]

I think I have found it after a wash to clear all the oil and a Night sitting to settle.I cranked it over without letting it start.The Diesel seems to be coming from the pipe that joins the Pump to the Injector,
I think plumbers PTFE tape will do it is it Diesel proof.
I cant see why it would leak it looks ok the nipple is formed by the pipe and the nut screws on well but dribble of diesel it does.
Bob

[sbrumby]

I dont know if ptfe is the ansewer, anything after the pump is under extreem pressure and anything that comes adrift will end up in the injector, at best pass through, at worst block the injector. You have to find what is leaking the pipe or the connection.

[johnfireball]

Hi,
I read somewhere that overtightening the pipe fittings can cause them to crack at the ends. PTFE wont work as the pipe doesn't seal at the threads but at the socket joint. On boat engines the pipes are sometimes annealed to prevent pourosity.
John

[Cockney Bob]

The pipe does not seem cracked however the joint at the pump/pipe leaks like a sieve
I wonder if I can get another pipe in this country.
The ends look Ok as well.

[albertaphil]

It sounds like a cracked injector line. I know you say that you can't see a crack, but the injector lines have fuel at several thousand psi running through them, so they don't need much of a crack to leak a lot of fuel. I don't have much experience with these small engines, but I had a VW that started dripping fuel...it wasn't until I held a light under the hood at night that I could see the fuel mist coming from one of the injector lines. I couldn't see any crack. Since your leak seems to be coming from the fitting, perhaps the crack is where the nipple at the end of the line joins the straight line. Perhaps it was over tightened and under-lubricated while tightening at some point. IMHO.

Cheers,
Philip

[Cockney Bob]

Thanks looks Like I am going to have to look for a new fuel lune and fittings then.
Bugger.

[Cockney Bob]

Fingers leggs and everything crossed it looks like I have cured it at least for the moment .Under a magnifying glass it looked like the solder holding the ferrule to the pipe was cracked.I put that end in the Flame of my camping stove let it get very hot and the solder seems to have run into the cracks and it runs no leaks hooray.
Still wait and see if it lasts.
Bob

[albertaphil]

Congrats! There's nothing like a $0.00 fix that takes 10 minutes. Keep us posted on the durability of the fix.

Philip

[Cockney Bob]

Still fixed 20 miles in heavy traffic.
The Bike had done a Thousand miles since the last problem so it was due some thing breaking or falling off.
It is amazing how much more power I have got since changing to a different air filter .I can now keep up a steady 50 .
Bob

[andrewaust]

And the worst thing with diesel fuel, it doesn't evaporate like petrol, so even a small leak from your filler cap can make a rather large stinky mess on a long run !

Great to see you found the problem Bob, looks like the initial job might have been poorly done at the factory.


A

[Diesel Dave]

They are not soldered...........

They are trepanned into shape from the end of the pipe.

Order a new one, fit it and forget it for the next 5000 hours.

Dave

[Cockney Bob]

Well it does not leak now it seemed soldered it had the colour of solder around the top.
Perhaps just annealing it in the flames worked.Where can I get another.
Bob

[Diesel Dave]

Bryco in Daventry:

http://www.bryco-diesel-engines.co.uk/contact.asp

Ask for a Lombardini 6LD400 pipe.

Dave

[Cockney Bob]

Thanks dave will buy one just in case.
Bob