How to take your 'Balls Out' and clear jets

[Blackhat400]

 What would the symtoms  be IF   oNe of the balls were loose .,  as i had running issues, took the carb to a mates ultrasonic cleaner,  , put carb back on ,and it  floods , fouling the plug, ,  he had messaged me, to say hes found a brass ball in the sonic-bath, , so it musta been loose,  its the small one not the big one at 6"oclock,
this problem has been erratic for weeks,  runs sometimes [ on 2 cylinder ] then , pops and runs on one,   

[johnb]

Why would you want to clean the 0.5mm dia passage from behind the brass ball to the emulsion tube?

As it's a dead end hole sealed by the brass ball how can it affect carburretion in any way?

To me it makes no difference whether the hole is blocked at the end with the brass ball or at the front or halfway through with dirt.

Am I missing the bleeding' obvious?

[Pielight]

It's not a dead end...there's a drilling on the brass ball side of the 0.5mm jet that connects to the air box via the float bowl and rubber hose (air supply to emulsion tube) - hence the presence of the said jet.

[Neil53]

Believe me, that 0.5mm jet needs to be clean for the bike to run properly at low revs

I chased a low speed running problem for a year or so and it was just caused by that jet being blocked!!

[Dagosr]

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

(Attachment Link)

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 ....

(Attachment Link)

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

(Attachment Link)

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

(Attachment Link)

And then 'The jobs a Goodun' !!

(Attachment Link)

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

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

 

SFbrain,
I have read in other posts on other 2 stroke sites that these balls need removed for the whole cleaning process but others do not reinstall the balls or any other type plug to close this area back off..??  Can they simply just be left out? or is there a reason that this should be plugged back up?  Thanks

[5port]

I have read in other posts on other 2 stroke sites that these balls need removed for the whole cleaning process but others do not reinstall the balls or any other type plug to close this area back off..??  Can they simply just be left out? or is there a reason that this should be plugged back up?  Thanks

If you don't replace the big ball on this standard carb, the air feed to the Air corrector gets the pressure at the bellmouth and, can get crudded-up with oil (it is only 0.5mm).  When I experimented with this and prototyped the grubscrew method, I tried a set of carbs with the ball/grubscrew left out. It caused a rich flat-spot at around 4500. It was cured by replacing the grubscrews. 
With the ball/grubscrew fitted, the air pressure to the air corrector (from the filter tubes) is probably higher than the bellmouth feed.
OTOH, if you are doing the Dale Alexander / Dave Freist  change to Primary type Needle jet, you DO leave the ball out and block the old air feed (on the inside edge of the floatbowl). 

5port

[Jonny Angle Iron]

Great write up Steve, very clear and concise! I'm going to be doing this to a few carb sets over the winter. Just to satisfy my curiosity, would you happen to know what is behind the the smaller ball? and will this need cleaning out also?

Cheers

Jon

[5port]

Great write up Steve, very clear and concise! I'm going to be doing this to a few carb sets over the winter. Just to satisfy my curiosity, would you happen to know what is behind the the smaller ball? and will this need cleaning out also?

Cheers

Jon

 The "smaller ball", next to the big one, covers the front of the drilling for Idle air, back to the Pilot jet.  You clean that passage by removing the Idle air screw, its spring and the Pilot jet then blow clear with carb cleaner and/or airline. 

5port

[Jonny Angle Iron]

Great write up Steve, very clear and concise! I'm going to be doing this to a few carb sets over the winter. Just to satisfy my curiosity, would you happen to know what is behind the the smaller ball? and will this need cleaning out also?

Cheers

Jon

 The "smaller ball", next to the big one, covers the front of the drilling for Idle air, back to the Pilot jet.  You clean that passage by removing the Idle air screw, its spring and the Pilot jet then blow clear with carb cleaner and/or airline. 

5port

Thanks 5port!

[Reving Kevin]

Thanks, very helpful post.

Tackled the job on my 250E carbs with no problems. When I drilled mine out I stuffed the main opening with rag to prevent swarf going in to the other openings (yes, I cleaned the other passages after the drilling op, not before). Also, try to clear the swarf out by blowing from the inside of the carb, not from where the ball was drilled out towards the small hole. A camera dust blower is useful for clearing the various passages if you don't have an air line.

The cheapy carb jet cleaning brush set from ebay was about useless as none of the rod cleaners were small enough, the brushes were ok for the emulsion tubes etc. I stripped some stranded wire and used that. Didn't completely solve my carb issue, but easy enough to do and a job ticked off the list. Thanks for a helpful guide.

[CBM]

Thanks, very helpful post.
The cheapy carb jet cleaning brush set from ebay was about useless as none of the rod cleaners were small enough, the brushes were ok for the emulsion tubes etc. I stripped some stranded wire and used that.

The bristles from a wooden wire brush (a whole "bunch" come out together) can be really good for things like carb & washer jets and nearly always available in a toolbox nearby.

[elram]

I have read in other posts on other 2 stroke sites that these balls need removed for the whole cleaning process but others do not reinstall the balls or any other type plug to close this area back off..??  Can they simply just be left out? or is there a reason that this should be plugged back up?  Thanks

If you don't replace the big ball on this standard carb, the air feed to the Air corrector gets the pressure at the bellmouth and, can get crudded-up with oil (it is only 0.5mm).  When I experimented with this and prototyped the grubscrew method, I tried a set of carbs with the ball/grubscrew left out. It caused a rich flat-spot at around 4500. It was cured by replacing the grubscrews. 
With the ball/grubscrew fitted, the air pressure to the air corrector (from the filter tubes) is probably higher than the bellmouth feed.
OTOH, if you are doing the Dale Alexander / Dave Freist  change to Primary type Needle jet, you DO leave the ball out and block the old air feed (on the inside edge of the floatbowl). 

5port

Hi 5port,

I am riding a  RD350A, US import with 360-02 carburetors. The carburetors in my bike do not have the bigger brass balls. I presume that the previous owner did remove the balls and did not plug.

My bike runs great. But, i am able start the bike without the choke even after having been parked for a week.

As you suggested in another thread, I took the air screw three full turns out and was still able to start the bike first kick, then removed both air screws and able to start with choke.

Engine dies the moment choke is on.

I inspected the choke plunger and found intact.

Do you think not plugging the ports has anything to do with the above anomaly?

[Motty]

I am riding a  RD350A, US import with 360-02 carburetors. The carburetors in my bike do not have the bigger brass balls. I presume that the previous owner did remove the balls and did not plug.

I think you will find the 360-02 carbs did not have the brass balls fitted, they came later

Have you done a "plug chop" to see how rich your bike is running?

[elram]

I am riding a  RD350A, US import with 360-02 carburetors. The carburetors in my bike do not have the bigger brass balls. I presume that the previous owner did remove the balls and did not plug.

I think you will find the 360-02 carbs did not have the brass balls fitted, they came later

Have you done a "plug chop" to see how rich your bike is running?

Thanks Motty,

Plug chop was not done, but this is how the plugs look like after a short ride in 3/4 throttle position.

[zed1015]

Unless you do a plug chop under load at the rev range you want to check then the colour of those plugs only indicates the running conditions at or near idle.