PHF32A vs PHF32C

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GeoffW
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PHF32A vs PHF32C

Post by GeoffW » Thu Feb 13, 2014 5:40 pm

Can anybody tell me the difference between the PHF32A type and PHF32C type carby bodies? I don't see any difference visually apart from the internal parts such as jet sizes, slides etc.

I know they put the PHF32C on some later 900SS models, so the reason I ask is if I put the same jets, slides needles from the PHF32A into the PHF32C types, will it not be the same carby as the PHF32A?

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Steve Foster
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Re: PHF32A vs PHF32C

Post by Steve Foster » Thu Feb 13, 2014 11:57 pm

Hi Geoff,
I wondered the same myself and found the following. Check out page 39 of this pdf document: http://www.guzzitek.org/documents/carbu ... oMAJ01.pdf
2.4 ENGINE CONNECTIONS
The carburettor is usually connected to the engine with one of the following:
A- male clamp fixing (figure 4)
used for the flexible fixing of the carburettor to the engine is usually recommended
on motorcycles for motocross, trials, etc or fitted to engines which run to high rpm
or those which produce strong vibrations.

B- female clamp fixing (figure 5)
with a rigid fitting to the engine, are usable on road motorcycles or fitted to
engines which do not generate very strong vibrations

C-flange fixing (figure 6)
with a rigid fitting to the engine, are usable on road motorcycles or fitted to
engines which do not generate very strong vibrations

Note that with the female clamp fixing and the flange connection, as you can see in figure 5 and 6, there is also the need to
provide both effective heat insulation and a perfect airtight seal.
My assumption is that the A and C type carbs have different engine connections but I haven't eyeballed a PHF C to confirm this. Maybe I am completely wrong but at least the link might be useful .....
Steve
1974 Ducati 750 GT

GeoffW
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Re: PHF32A vs PHF32C

Post by GeoffW » Fri Feb 14, 2014 1:08 am

Thanks for trying to answer my question Steve, but both PHF32A and PHF32C types that I'm referring to have the female clamp type fitting (i.e. fitting type B).

See below:
IMG_1174 - Version 2.jpg
PHF32CS from 900SS or Darmah

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BevHevSteve
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Re: PHF32A vs PHF32C

Post by BevHevSteve » Fri Feb 14, 2014 6:15 am

Darmah has phf32cd/cs carbies, they have a tiny little jet installed down deep under the pilot (idle) jet from what I have heard is for DOT emissions (SMOG). Otherwise they are the same as the phf32as/ad carbies.
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GeoffW
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Re: PHF32A vs PHF32C

Post by GeoffW » Fri Feb 14, 2014 12:20 pm

Thanks Steve, I'll have a closer look at that bit of the carbs. These came off an SS but that will be the same as the SD.

machten
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Re: PHF32A vs PHF32C

Post by machten » Mon Feb 17, 2014 4:27 am

Steve is correct, there is another "jet" underneath the A series idle jet. There is one other potential difference...the idle mixture drilling may be different to accomodate a longer and different shaped idle mixture screw with the intent of provisioning some finer adjustment to reduce emissions. There may well be no difference at all in the drilling and it's all down to the needle, but might be worth checking.

CS/CD mixture needle at the bottom, AS/AD at the top.

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Kev

GeoffW
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Re: PHF32A vs PHF32C

Post by GeoffW » Tue Feb 18, 2014 3:23 am

Thanks Kev, I must pull out all the bits and have a really good scrute!

Geoff

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