Need to clarify the Bing carb needle o-ring upgrade set-up.
I have no idea how it is done in the carb assembly since diagram is unknown.
My R277 need this update. Also, kindly looked at the photo from AS if this the right item? Thanks.

From California Power Systems (CPS):
The JET NEEDLE should have a tiny o-ring on it, about 3/16 inch in
diameter.  This o-ring should slide down over the top of the JET NEEDLE and
snug up against the E CLIP.  The purpose of this o-ring is to keep the JET
NEEDLE from spinning inside the E CLIP, and getting sawed in two.  If you
don't have one of these o-rings, order one from California Power Systems.
Part #963-505.  Don't fly without it!

Thanks!, Joe.,
Regards,
Phil

If you are ugrading from a carb needle that has no o-ring, don´t you also need a new cup? See below:
http://ultralightnews.ca/bing/needleclipupdate.html
The Rotax Service letter: http://ultralightnews.ca/bing/bingupdate.pdf


Regards
Petter

I believe you meant "clip" instead of cup. Yes, I would also replace the clip in  case it was worn as well. A quick test, if the clip can be spun around the needle with little or no force, replace it.

I should have added, replace all three parts: Needle, Clip, O ring. Be sure you order the correct needle and seat the clip in the correct groove for your situation.

Quoted from joe.scalet

I should have added, replace all three parts: Needle, Clip, O ring. Be sure you order the correct needle and seat the clip in the correct groove for your situation.

What Joe said.  The mid-range needle jets wear over time.  

You can determine the proper clip position by observing your EGTs in the 4000-5500 rpm range.  I generally adjust mine twice a year,  late spring and late fall.

Quoted from joe.scalet

I believe you meant "clip" instead of cup.

Hi Joe. I meant cup. Think it is called needle cup. The new cup has a recess where the o-ring fits. And if you look at the Rotax Service letter, the new cup and old cup has different part numbers.

Regards
Petter

Ok, you're referring to the plastic slide part # 827-347 that the connects the throttle cable and needle?

Quoted from joe.scalet

Ok, you're referring to the plastic slide part # 827-347 that the connects the throttle cable and needle?

Yes, correct. Rotax calls it "spring cup".

Thanks very much Petter for the information. I will check my 447 carb this spring. I know that the O ring is there, cause I put it there, but I had no idea that a new clip and spring cup was involved in the update.

Does the 'new clip' has part number?

Quoted from Phil

Does the 'new clip' has part number?

Acording to this: # 963 500

Thank you, Guys. For very informative comments. I ordered from LEAF today.