Atomiser bush

Paul Marx

Paul Marx

Hero member
Location
France
I'm rebuilding the carbs of my 3C project. Very dirty they are.
They've been dismantled and have gone through the ultra sonic bath. All's fine except one thing. Impossible to get the atomiser/needle jets out.
I've used heat, WD40 and even an impact driver.
I believe that the impact driver has made things worse. The jets are turning a bit but really marginally and I think that the impact driver has spread the head of the jet and that it's coming stuck against the thread for the main jet holder.

The only solution I see is to drill the heads off the needle jets and then, either the rest of the jet will unscrew, or I can knock the rest of the jet out towards the carb body, slide side, with its holder which is a press fit in the carb body.

Thoughts?

Paul
 
Thanks Thomas.
The head has broken off one of the atomisers with the impact driver so I'll have to drill.
I'm not a fan of those left hand turn things to get broken screws out.
In steel, they usually break, and this being bronze, and soft, the risk is expanding the bronze too much.

My initial concern was whether if unscrewing fails, how could I knock the whole lot out, seat included?

We'll see.

Paul
 
When you have sprayed WD40 you can "bounce" the nozzle with a long screw/steel with a hammer. That loosens up and the WD40 can better penetrate.

If the material of the nozzle at the bottom is still intact, you can alternatively drill a hole and cut a small M4 or M5 thread into it.
After thread cutting, clean the thread with brake cleaner or acetone.

Then screw in a hexagon socket screw with high-strength Loctite and glue it.
Wait at least 6 hours and then turn the screw with high force or an smal impact-driver out.

That might work.

Alternatively, if I that would happen in the desert:

I would drill a long hole (measure how deep beforehand!) in the nozzle assembly and solder a round steel piece there, that you bend at right angles (e.g. 10 cm) outside the carburetor housing.

After it has cooled down, use the blow dryer/gas burner to warm up the carburetor and then screw it out.

Good luck, Thomas aus LAU
 
Paul Marx said:
Thanks Thomas.
The head has broken off one of the atomisers with the impact driver so I'll have to drill.
I'm not a fan of those left hand turn things to get broken screws out.
In steel, they usually break, and this being bronze, and soft, the risk is expanding the bronze too much.

My initial concern was whether if unscrewing fails, how could I knock the whole lot out, seat included
Click to expand...
Can't give an informed opinion on knocking it out, but I'd be inclined to try a left hand drill bit first. I've never had much luck with the left hand turn extractors but I've had reasonable results with left handed drill bits - the worst outcome is that it drills out whatever is stuck but more often than not it snags at some point and unscrews the offending item. This is a time for slow and steady rather than whacking the drill onto full tilt boogie :)
 
Got tips today via Ducati Paddy and Keith Nairn.
The head of the atomiser, wider than the shaft, rests on a lip in the carb body. That allows to hold the seat in as well as the atomiser.
If I can cleanly drill the heads off the atomisers, that will allow to knock the rest of them out of the top along with the seat.

Paul
 
Got them.
The needle jet rather than atomiser is 6mm wide. So, I took a 7mm drill and drilled the heads off.
Sounds simple only I have a single speed Chinese pillar drill of 1990s vintage and nothing very appropriate to hold the carb under the drill. And I lack experience but taking time is the secret.
So, that's one set of triple carbs well on the way to resurrection.

PaulDSC_1965.JPG20210210_161147 (Petit).jpg20210210_162108.jpg
 
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