Air Bleed

[Diesel Dave]

For me one of the biggest pains in diesel biking is running onto reserve.

It takes ages for the air to clear out of the feed line and the bike runs like a dog during this time.

Bleeding the feed lines would require loosening of the unions and spilling loads of fuel out of the system to clear the bubbles.

Near vertical fuel lines help as this allows the bubbles of air to rise but I had a problem as it would gather in the fuel filter and it was tricky to bleed the air out.

So with a spot of epoxy and an old bicycle inner tube 'presta' valve:

,

So by loosening the valve I can bleed out the air without the need for tools.

Time will tell if the seals will stand up to the diesel fuel.

Cheers
Dave

[Stuart]

Nice one Dave Amazing what you can do with some old bike parts and a tube of glue. Bet it was a pain to de-grease the area before the sticky stuff went on I use a can of painters solvent for my needs. Good stuff by highly inflammable

[andrewaust]

Yeah! Great little invention there mate, I remember when I had to have a fuel cut off solenoid near the pump and the switch went open circuit creating all sorts of problems "on the side of the road" trying to bleed the damn thing when I bypassed the fuel cut off.

Diesel fuel is a P.I.T.A, the seal on the fuel tap decided to crap itself through the week, because both bikes are chained together its a squeeze to get around and I must have slightly knocked the tap on a little which ended in approx 3 liters of Diesel on the cement. As the bikes have covers I didn't get to see the mess till the next day = GGGGRRRRR.

So it was an O-Ring fix along with a quick bleed, which leads to why I have stated the above - something that gives a quick alternative to bleeding the lines without physically pulling some off has to be the Ants balls / Ducks nuts



A;)

[Diesel Dave]

I only have 2 ways of degreasing:

1) Carb Cleaner

2) Cellulose thinners

Seems to work.

[coachgeo]

ok..... your going to get made at me butt... ahhhhh

they make three port fuel filters just for this. Well sorta just for this.

They are for gasser cars prone to vapor lock without them. 80's 90's era I think. There are many configurations (where the third port is). Third port was for bleeding fuel vapor back to the tank where it condensed back to liquid.

Find one at your fav. cheapo Auto parts and plumb a line off the third port to an air valve like yours or find a way to do like many older MB diesels do. Just run it to the tank as long as the tank is vented. Any fuel that goes up the line goes back into the tank.. Any air that makes it there gets vented out.

are bike fuel tanks vented?

Fancy way I guess would be if your custom building then weld in a small tube that goes up from bottom of tank thru the inside and out the top. Hole drilled in tube just below tank's top. Weld the tube to the top on the outside. Cut it of flush and weld it closed. Grind it down so its invisible. Only suggesting welding to top for added strenght. Maybe a one way valve in this tube to let fuel and air up.. but none down. Then you could plumb the third port for bleeding air into the bottom of the tank and let it send air and any other fuel up thru it to the top of the tank and out that hole drilled in it, Whala..... a fuel return that bleeds air.

easier option might be (if the tank is vented) is to drill a hole in the fuel cap and plumb the third port into that. Would look sorta like the old dirt bikes that had a hose on the fuel cap. What the heck was that for? Vent Im guessing

[Darren]

Would look sorta like the old dirt bikes that had a hose on the fuel cap. What the heck was that for? Vent Im guessing

Na - its in case you get a bit thirsty while your out riding

On a more serious note. I think my Hatz IB30 may self bleed. something going on with a return into the bottom of tank (with pipe going up to top inside tank) The return from the injector goes up to this so does a second pipe from the injection pump - there is a suspect plastic part in this hose just above the pump, which I guess is a one way valve or a restrictive orifice??? Not had a look yet.....

[Sphere]

Did you just leave the hatz exhaust and tank in place Darren? Any pics about?

[Darren]

I cheated and bought it.

Think its a Charnwood conversion. Possibly played about with since it left them?

I dont have any pictures on the computer although I think some got posted when I bought it a couple of years back.

Stainless pipe from the barrel down into what I think is a standard Enfield muffler.

The Hatz fuel tank is not there.

Just found a photo of it on yahoogroups

[thundercougarfalconbird]

hatz uses a really nice filter set up, it is self bleeding and it has water drain, the part number is 50539200 .
the air bleed goes to the top of the fuel tank on the engine
the only problem might be the small 1/4 inch fittings on the filter, depends on your application

[Sphere]

[Sphere]

Mounted part bottom right corner:

[Darren]

yeah nice little filter.... gonna get me one of them.

[thundercougarfalconbird]

you might rethink that filter when you get a price on it

[Diesel Dave]

Remember you will need to run the vent pipe to a height above the tank filler too.

It's a bit awkward but if it's a clear pipe you can use it as a tank level gauge - the original batch of Robin Enfields had this feature.

Dave