PHF32 Air Passage Question/ Kara

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Tinkerbell
Mariana
Posts: 48
Joined: Sat Sep 05, 2020 3:57 am

PHF32 Air Passage Question/ Kara

Post by Tinkerbell »

Hi Everybody,
I am putting new bits in my PHF32As and checking all the passages. As you face the intake side of the carb, there are three air intake holes at the bottom of the main bore. The hole on the right seems hard to pass air or solvent through and this is true on both carbs. Where does this passage go? what does it do? and how easy should it be to blow air through it ? I seem to be able to only pass a tiny airflow through it . When I shine a bright light down the passage , it looks clean but there is what looks like shiny metal way down in the center of the passage. Could this be blocked off at the factory? Both carbs behave this way.
Very Sincerely,
Kara
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Craig in France
Paso 750
Posts: 949
Joined: Tue Mar 23, 2004 3:58 pm
Location: Montpellier, France

Re: PHF32 Air Passage Question/ Kara

Post by Craig in France »

Hi Kara and welcome to the Forum,
Tinkerbell wrote: Sat Sep 12, 2020 6:11 pm<snip>The hole on the right seems hard to pass air or solvent through and this is true on both carbs. Where does this passage go? what does it do?
Ah! I can understand your confusion ...

It's a blind drilling! :-D :shock: See the photo below of a Dell'Orto PHF32AD which shows it ... more clearly ;)
Carb.jpg
The most important thing is to make sure that the drilling on the left is really clear. It is stepped internally which makes a great place for fuel crud to accumulate. And since it supplies air for the idle circuit, it needs to breathe free.

Instructions on how to check, even after ultra sonic cleaning, below:

Checking the galleries with carb cleaner

The easy way to check the galleries (with the carbs on or off the bike) is:
1. Remove the pilot jet and the mixture screw.
2. Using a can of carb cleaner with an extension tube fitted, put the tube up the hole where the pilot jet goes. Cover the mixture screw hole with a finger and squirt cleaner while looking for a stream coming up into the venturi, just in front of the back edge of the slide.
3. Now put the tube in the mixture screw hole. Cover the pilot jet hole with a finger and squirt cleaner whilst looking for a stream coming out between the slide and the engine.
4. Now put the tube into the little air hole under the main carb air intake (not the "middle" one: the one on the side). Squirt, and look for cleaner in the venturi.

HTH

Craig
Tinkerbell
Mariana
Posts: 48
Joined: Sat Sep 05, 2020 3:57 am

Re: PHF32 Air Passage Question/ Kara

Post by Tinkerbell »

Hi Craig,
Brilliant! I looked with a glass way down inside and it looked like a bronze color plug but I am new to the PHF world. All the other passages blow clear and the carb was spotless inside upon disassembly. THANK YOU for moving the project forward!
Sincerely,
Kara
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Craig in France
Paso 750
Posts: 949
Joined: Tue Mar 23, 2004 3:58 pm
Location: Montpellier, France

Re: PHF32 Air Passage Question/ Kara

Post by Craig in France »

Tinkerbell wrote: Sun Sep 13, 2020 7:51 am <snip> ... I am new to the PHF world.
Well, they're not so bad, delivering both reasonable economy and performance. They do like to be set up right, but once done they remain remarkably stable.

Watch especially for getting the float height right; and for simple things like making sure the choke piston is sealing properly (it's actually an enricher, btw, not a choke). The slides wear a bit, but no more than is reasonable (until some clown decides to remove the air filters ...). And spares are still - by and large - available.

If in any doubt, Steve sells his own manual on setting them up, as well as the original Dell'Orto manual. The latter can sometimes demand a little bit of interpretation :) , but it's all good.

https://store.bevelheaven.com/Manuals-F ... rto-Carbs/
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