Author Topic: How to take your 'Balls Out' and clear jets  (Read 12142 times)

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Offline Sfbrain

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How to take your 'Balls Out' and clear jets
« on: January 27, 2017, 11:27:55 AM »
Hi Guys,

I've got to the carbs on the 350B's restorations, first job is to take the brass balls out so that the air correction jets can be cleaned and cleared.

This is a topic that frequently comes up in the forum so i will document it clearly, with pictures, so you might be encouraged to have a go yourselves.

Strip the carbs of all the jets and choke mechanism etc etc

This is the method i use but i'm sure there are others.

So here we go, these are the brass balls that are discussed and are approximatly 5mm in diameter and solid spheres of brass.



Hold the carbs securely (i have them in my vice) and then, with a fine point centre punch make a small centre punch GENTLY, my tip here is to do it at approx a 45 degree angle to the verticle, this is because if you hit straight down on the ball then you are more likely to knock the ball down into the tube.



I use a battery hand drill because they are designed for drilling and putting in screws, this means the spin of the bit is variable, i.e. the tighter you squeeze the trigger the faster the drill bit/screw bit rotates.

I use a 1.5mm drill bit and very gently place the tip in the centre punch mark and rotate the drill bit VERY GENTLY with minimal pressure.



So with patience and gentle pressure you can increase the drill spin speed until the bit gets a good hold, then gently drill completly through the ball.

When you have gone through remove the drill bit from the drill and place it through the hole in the ball upside down (drill bit shaft first)



Now gently holding the drill bit, rotate the bit and the ball will start to rotate in the tube. Keep rotating gently until it becomes more free.

When it rotates freely gently start to ease it upwards, take your time and eventually the ball will pop out still on the drill bit.



Now the carb body is ready for my ultra sound tank



If you think there wont be any crap behind the balls here is a picture of a cotton bud that has been twisted up the tube after 30 mins in my cleaner



Next post will cover cleaning all the airways and jets

More soon

 ;)
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Offline ozmadman

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Re: How to take your 'Balls Out' and clear jets
« Reply #1 on: January 27, 2017, 11:47:14 AM »
Excellent, look forwardto the next instalment ;)
"Tolerance and Apathy are the last virtues of a dying society" Aristotle

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Offline Pielight

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Re: How to take your 'Balls Out' and clear jets
« Reply #2 on: January 27, 2017, 02:47:46 PM »
Your thread will be a good help for future ball extracters. I used a near identical technique - except I only drilled just over half way through the balls and used a Dremel to drill for good control - I was very pleasantly surprised how easy they come out (I also used a bit of WD40 to help free the balls). Not drilling right through the balls meant they could be reused (and being ready drilled for future balls out ops)  - however I used 5ports excellent idea of replacing the balls with brass grub screws (after tapping holes) that he posted in the skills centre.

Offline shaunthe2nd

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Re: How to take your 'Balls Out' and clear jets
« Reply #3 on: January 27, 2017, 05:53:06 PM »
Some great advice there thanks.
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Offline Sfbrain

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Re: How to take your 'Balls Out' and clear jets
« Reply #4 on: January 28, 2017, 10:00:05 AM »
Episode 2 here, this post will cover clearing the jet/air ways.

First you will need these tools, a set of jet files and WD40/Carb cleaner, and if possible access to an air line.



There are 2 very small air/fuel ways that need to be clear.

The first one i'm going to cover ir the one behind the brass balls. With the balls removed and the tube behind cleaned out (Cotton bud soaked in WD40) you will see at the bottom of the tube a non-removable brass jet. The hole in the centre of this jet is 0.5mm.
This airway travels from the brass jet, through the main casting and comes out in the needle jet tube (the main vertical tube in the casting where the emulsion tube/jet sits).

Taking the 0.5mm jet file, insert into brass jet behind ball



With a little jiggling about you should be able to push the file all the way through to the center tube



Gradually work the file in and out until you are happy that this jet/air way is now clear
(this can take a while, so far i've only managed to clear one of the carbs for the 350B's project, the second is blocked solid so is getting trips to the ultrasonic tank, being soaked in carb cleaner and being 'worked' on with the file)

The second jet/air way to clear is the 'tick over' jet (thats what i call it  ;) )
It is in the engine side of the carb through channel.
There are 3 'holes' in the bottom of the main carb through channel that are just after the main needle jest apperture.

From nearest to needle jet towards the engine, they are :-

First one is the pilot jet apperture, (which comes out under the slide)
Second one is at an angle toward engine and is the 'tick over'jet
Third one is the oil feed from the oil pump

This pic is the 'tick over' jet



Its hole size is also 0.5mm and travels down at an angle of about 30 degrees and exits into the smaller tube that contains the pilot jet.
When you have your throttle closed and the carb slides are bottomed out in carbs, then the 'tick over' jets draw fuel up from the float bowl, through the pilot jet tube, up this fuel way and sprays a fine spray of fuel into the engine (when carbs are closed shut)

The 0.5mm jet file also fits in this jet



Although i couldnt photograph it, you can look down through the top of the carb, look into the pilot jet apperture (number 1 in above description) and see the jet file appear in the pilot jet tube  ;)

With these two jet/air ways clear the likely problem areas are cleaned out. Obviously the main appertures for needle jet and pilot jet etc etc needs to be clear and clean. Use cotton buds and WD40/carb cleaner  to do this.

Dont forget this drilling in the Choke carbs' float bowl ...



The hole at the bottom of the cast tube needs to be clear into the tube, this is where fuel for the choke is drawn from.

Next post will be replacing the removed brass balls (with grub screws)

 ;)
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Offline ozmadman

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Re: How to take your 'Balls Out' and clear jets
« Reply #5 on: January 28, 2017, 03:07:42 PM »
Very self explanatory, a great help ... I have done this with my carbs but the wire you are showing here looks a lot thicker than what I have used and I am surprised you manged to get it through the jets???  My wire measures .4mm and that seems a tight fit.  The choke tube drilling looks smaller??  cheers
"Tolerance and Apathy are the last virtues of a dying society" Aristotle

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 1960 Model 8 AJS 350cc.

Offline Sfbrain

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Re: How to take your 'Balls Out' and clear jets
« Reply #6 on: January 28, 2017, 07:20:41 PM »
Very self explanatory, a great help ... I have done this with my carbs but the wire you are showing here looks a lot thicker than what I have used and I am surprised you manged to get it through the jets???  My wire measures .4mm and that seems a tight fit.  The choke tube drilling looks smaller??  cheers

The carb spec for 'air corrector jet' (behind ball) is 0.5mm, maybe start with 0.4mm to get it clear but 0.5 should go through eventually.

The choke tube drilling is not a jet, it is just the feed to the tube. The main choke carb body has a brass tube (which should be clear) that drops down it the cast tube in the float bowl, so the hole at the bottom of the tube is just a feed to allow fuel to be drawn into the tube and then sucked up the brass tube into the choke, So not critical on size just needs to be clear.

 ;)
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Online 5port

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Re: How to take your 'Balls Out' and clear jets
« Reply #7 on: January 28, 2017, 08:10:59 PM »
The choke tube drilling is not a jet, it is just the feed to the tube. The main choke carb body has a brass tube (which should be clear) that drops down it the cast tube in the float bowl, so the hole at the bottom of the tube is just a feed to allow fuel to be drawn into the tube and then sucked up the brass tube into the choke, So not critical on size just needs to be clear.
 ;)

Hi Steve.  Great thread! The "balls" subject is one of the things that fall outside the manuals but, probably effect most aircooled RD's! As far as the "Choke" tube in the floatbowl goes, I think it is more of a dashpot. When the "Choke" is on, it opens the path for the fuel to rise up the pick-up tube, mix with air in the plunger housing and then go into both inlets.  The dashpot which the pick-up tube sits in gives a good slug of fuel in the first turns of the engine with the choke on but, as the entry to the "dashpot" is limited at the bottom by the #70 hole, the fuel level in it rapidly drops as the engine runs until, the bottom of the pick-up tube is partly exposed to air (the dashpot is open to floatbowl air at the top) and the "choke" mixture is weakened to match the small #70 flow.  I think this is reflected in the way that the pick-up tube goes into the dashpot, rather than just sticking down into the fuel in the floatbowl and, the starter "jet" size is specified in the carb spec.  Overall, the starter dashpot is an efficient way to arrange a very rich initial start mixture that automatically reduces to just a rich mixture after start, using just an "On" / "Off" lever with no real variable adjustment.   ;)

5port

   
« Last Edit: January 28, 2017, 08:14:08 PM by 5port »
5port

Offline Jonny Angle Iron

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Re: How to take your 'Balls Out' and clear jets
« Reply #8 on: January 29, 2017, 12:34:26 AM »
Good info Sfbrain!

Nice to see well documented posts like these. They make the seemingly impossible accessable to the masses which can solve a whole load of "mystery problems" folk get from time to time.

 
All it took was 2 strokes and I was hooked!

Offline Sfbrain

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Re: How to take your 'Balls Out' and clear jets
« Reply #9 on: January 29, 2017, 12:46:53 PM »
Here is the 3rd and final Episode (Replacing your Balls !! )

You will need ......

Brass 5mm grub screws (I use allen head)
5mm tap
Loctite
Allen keys
Thread guage



First thing to do, for peace of mind, is to use a thread guage to check the thread pitch on the grub screws.
You wouldnt want to tap a wrong pitch thread into your carbs.
Mine are M5x0.8

Gently start to tap the thread ....



You will need to tap to roughly 4 to 5 complete turns of the tap, but if it goes real tight STOP !! you may have reached the bottom.

Once tapped, i go to my air line and blow out any swarf created when tapping, then i just check the jet is still clear with my 0.5mm jet file.

Next put a grub screw on the end of an allen key and apply a thin film of loctite



And screw into your tapped hole, screw in until it starts to tighten.



And then 'The jobs a Goodun' !!



Nice thing is, the next time you need to clean the jets it is much easier to do  :D

Hope that shows that it is not difficult to 'Get Your Balls Out'

 ;)
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Offline Motty

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Re: How to take your 'Balls Out' and clear jets
« Reply #10 on: January 29, 2017, 06:40:36 PM »
You have made the job look easy  :o
Thank you for taking the time to document it  :)
Although I suspect that the rivet counters will now start inspecting everyone's carburetors for "modifications"  :D
« Last Edit: January 29, 2017, 06:42:21 PM by Motty »
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Offline shaunthe2nd

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Re: How to take your 'Balls Out' and clear jets
« Reply #11 on: January 29, 2017, 10:21:13 PM »
Good posts, thanks, love these tips.
RD350LC - RD250LC - RD200DX

Offline Ozhammer

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Re: How to take your 'Balls Out' and clear jets
« Reply #12 on: February 09, 2017, 01:30:59 AM »
Steve, what length are the brass grub screws and where can they be purchased from?

Cheers
Ozhammer
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Offline Sfbrain

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Re: How to take your 'Balls Out' and clear jets
« Reply #13 on: February 09, 2017, 08:37:08 AM »
Steve, what length are the brass grub screws and where can they be purchased from?

Cheers
Ozhammer

Not sure of length, they are approx 5-6mm in length.

Bought them on Ebay, they came from China, all i did use was 'M5 Brass Grub Screw', then made sure mine were Allen socket heads.

 ;)
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Offline paul n

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Re: How to take your 'Balls Out' and clear jets
« Reply #14 on: February 09, 2017, 09:01:58 AM »
Thanks for the clear instructions Steve. 4 carbs done then a trip to Allens for some new jets. Just waiting for my grub screws.  ;D
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