Eddieb's DR build thread.

[Woodman]

Sometimes ya just crash.

On intotallmunters, I have found that front end type washout crashes have dramatically decreased since I have had them installed. In fact to me its their best feature.

Get well soon.

[Monstaman]

Sometimes ya just crash.

Yeap just that, sometimes shit just does happen, WP, Ohlins, Penske or whatever, psycho analyse all of it and sometimes slippery shit with an off camber face etc ....

Get well soon.

And that!!

[Eddieb]

Well I'm getting more mobile so it's back into the DR farkling again. Not long before my accident I tried fitting a FCR39 carb but when I connected it up to the tank to set up the accelerator pump I discovered it leaked everywhere.

While I've been out of action a rebuild kit arrived from ProCycle and tonight I fitted that to the carb. The rebuild kit basically consists of a float bowl o-ring, carb top o-ring and a new float bowl piston thingy(technical term).

I've fitted the rebuild kit tonight and the leak from the float bowl has stopped, but that has shown that it's also leaking from the accelerator pump cover. The pump cover is a metal mating surface with no o-ring to seal it. Having a look at the surface I can see some score marks on the carb surface which are near, but not exactly where the worst of the leak is. The leak occurs when the pump does it's thing and squirts out from between the 2 parts.

1) It didn't really come out but the scoring is above the 858 on the pump diaphragm to the right of the threaded hole, but the leak appears to be at 9 oclock where the diagional hole is
2) It seems I am also missing part # 52 from this piece as shown in the exploded diagram, but I have my suspicions that it was actually there when I removed the cover and went awol while the cover was off


Any ideas? I'm almost ready to flag fitting it and staying with the stock BST40 at this stage. Would there be any advantage in disabling the pump and fitting the carb by removing the pump rod or something?

[NordieBoy]

The diaphragm and o-ring are the seals.

[NordieBoy]

Would there be any advantage in disabling the pump and fitting the carb by removing the pump rod or something?

On quicker throttle openings, it'd go very lean.

I can check my spare carb and see what condition the cover, o-ring and diaphragm are in...

[Eddieb]

The diaphragm and o-ring are the seals.

So what does part 52 do? it's not an o-ring, more like a plastic washer with a hole in it.

When the pump is pressed there's more fuel coming out of the bottom of the carb than is getting sprayed into the carb, like a lot of fuel.

[zeRax]

you have a SPARE fcr fran? what a hordieboy

[Tony W]

Would a holed diaphragm cause this leaking?

[Eddieb]

On quicker throttle openings, it'd go very lean.

I can check my spare carb and see what condition the cover, o-ring and diaphragm are in...

That would be cool if you could see what is in the hole in the cover. The cover looks fine, though there are slight polishing marks on them from manufacture if you move it under a light. The diaphragm looks fine too and is certainly producing a fair bit of pressure as the leak is spraying out of the carb, not just dribbling down the side of it.
The marks on the body are really what concerns me, they look quite deep though I can't really feel them with my finger, and the missing piece of course.

[GSers]

Eddie you can surface the accelerator pump housing take out the spring and use a fine sheet of sand paper 600 grit on a piece of glass (garage window etc) move it around on the glass in a figure 8 then clean it out and blow off with compressed air. This will help remove those groves and make sure the surface is flat across all the retaining screw surface. Make sure the jet where the fuel is supposed to come out in the venturi is not blocked if it is then that could be a reason it is blowing out the side of the housing. There should be to check valves in the circuit that is one in that bottom housing the ball bearing in the hole. make sure they are also both free.
Hows the ankle by the way?
GSers

[Eddieb]

Eddie you can surface the accelerator pump housing take out the spring and use a fine sheet of sand paper 600 grit on a piece of glass (garage window etc) move it around on the glass in a figure 8 then clean it out and blow off with compressed air. This will help remove those groves and make sure the surface is flat across all the retaining screw surface. Make sure the jet where the fuel is supposed to come out in the venturi is not blocked if it is then that could be a reason it is blowing out the side of the housing. There should be to check valves in the circuit that is one in that bottom housing the ball bearing in the hole. make sure they are also both free.
Hows the ankle by the way?
GSers

Cheers Gerard, the grooves are on the carb body though so thats a bit more awkward.

[NordieBoy]

you have a SPARE fcr fran? what a hordieboy

Yammy racer one that doesn't have a leak jet or enrichener.
Good for spares though.

[cooneyr]

Might be a dumb question - never opened a FCR before. Whats the outter diameter of the little O-ring in comparison to the hole that part 52 would sit in? Is part 52 needed for the O-ring to seal against? The outer edge of hole on the cover is very thin for the O-ring to seal against.

Hope this makes sense, and helps.

Cheers R

[NordieBoy]

So what does part 52 do? it's not an o-ring, more like a plastic washer with a hole in it.

When the pump is pressed there's more fuel coming out of the bottom of the carb than is getting sprayed into the carb, like a lot of fuel.

It's known as "U-Ring" in the parts manuals.

[Eddieb]

It's known as "U-Ring" in the parts manuals.

Thanks Fran. Sudco stock all the replacement bits in that part of the carb, in theory if I replaced the o ring, diaphragm and u-ring should the leak go away?