Dellorto PHBH

[mnpes]

A Cheap n Cheerful Carb ........

Martin of Justlambrettas being a good source and a gentleman to deal with

Presently using a 30mm phbh on Inspector Gadget
Blue-printed Stage 4 - Cast 200

Settings @ present
mj 118 ~ 70 choke ~ 55 idle jet ~ av264 atomiser ~ x7 - 2nd clip
40 slide ~ Uniflow remote filter ~ 2 screws out

Onboard Instrument readings on this set-up ~ YESTERDAY :biggrin:

Tickover lovely air fuel ratio reading ~ slightly lean @ pull away ~ Anything above slightly rich
Throttle backed off @ 60 - 65 slightly rich .......... Full throttle slightly rich .....

Very rare can 1 carb setting be used on another engine without some fettling

Even an engine set up lovely one-day can and does change another
Lots of X - factors ~ Weather - Fuel - Height above sea level etc

[soosh]

Probably. I'm sure mineral oil does that.
You must take this seriously young man,your humour is being monitored so "spring" back into line.

A flat line?

Washer your mouth out and get back on topic.

[Adam_Winstone]

He did polish the needle slightly but when it was worn,I replaced with std.X13 and kept fingers crossed as i don't use egt. All good

What kind of polish did he use?

Mr. cLEAN

[soosh]

Very rare can 1 carb setting be used on another engine without some fettling

Sure thing,apart from Piaggio knocking out a few of million V50`s/VNB`s/PX`s etc on the same carb/spec.

[nelson pk]

Very rare can 1 carb setting be used on another engine without some fettling

Sure thing,apart from Piaggio knocking out a few of million V50`s/VNB`s/PX`s etc on the same carb/spec.

Maybe so but you wouldn't jet a PX125 the same as a PX200 if you used the same carb would you?
Same as you wouldn't expect to jet a casa small block the same as a muggy 225 on the same carb would you

Someone like piaggio would have had strict manufacturing tolerances and jetted the carbs with enough safety margin to allow for possible slight manufacturing differences.
However a scooterist in his shed, building an engine with the same exhaust, kit and carb as another scooterist in his shed is not going to have those strict tolerances that piaggio had, so jetting for the 2 may be different.

[Muttley McLadd]

Someone like piaggio would have had strict manufacturing tolerances and jetted the carbs with enough safety margin to allow for possible slight manufacturing differences.
However a scooterist in his shed, building an engine with the same exhaust, kit and carb as another scooterist in his shed is not going to have those strict tolerances that piaggio had, so jetting for the 2 may be different.

But it may be the same.

[nelson pk]

Someone like piaggio would have had strict manufacturing tolerances and jetted the carbs with enough safety margin to allow for possible slight manufacturing differences.
However a scooterist in his shed, building an engine with the same exhaust, kit and carb as another scooterist in his shed is not going to have those strict tolerances that piaggio had, so jetting for the 2 may be different.

But it may be the same.

"maybe" is exactly the point. My example was of 2 people with the same exhaust, kit and carb and the jetting may just be the same.
Take two people with the same carb, different kit and different exhaust..................whats the likelyhood of the jetting being the same now????
That was my point in the first place.

[soosh]

Someone like piaggio would have had strict manufacturing tolerances and jetted the carbs with enough safety margin to allow for possible slight manufacturing differences.
However a scooterist in his shed, building an engine with the same exhaust, kit and carb as another scooterist in his shed is not going to have those strict tolerances that piaggio had, so jetting for the 2 may be different.

But it may be the same.

"maybe" is exactly the point. My example was of 2 people with the same exhaust, kit and carb and the jetting may just be the same.
Take two people with the same carb, different kit and different exhaust..................whats the likelyhood of the jetting being the same now????
That was my point in the first place.

Depends if you have a carb finely tuned or good enough to run smooth but allow for any issues.I dont run finely tuned carbs,there is still more to get out of it but the spec i had allowed me to change the pipe,piston skirt had a trim and still fine so it is a now a different kit,not a lot but performs different.The spec Special X originally quoted for a 28 is deff where id start and id ask for that when running a piston port kit,id expect to adjust the main slightly or even needle postion but a great starting point but thats the spec i ended up with and was quoted before it was dynoed so its pretty consistant.Another example is my TS which is far from std but was kindly given a spec from Jerome even though i didnt get the carb from him and it was bang on.Again,if you wanted it finely tuned for max performance then you would need to replace a few bits but its smooth,not spluttery and ive had no issues.
As far as Piaggio having stric tolerances,maybe but im still trying to suss out how some of my mates years ago had PX125`s that were quicker than some P2`s or P2`s that could go right off the clock while others struggled to hit just over 60.

[nelson pk]

Depends if you have a carb finely tuned or good enough to run smooth but allow for any issues.I dont run finely tuned carbs,there is still more to get out of it but the spec i had allowed me to change the pipe,piston skirt had a trim and still fine so it is a now a different kit,not a lot but performs different.The spec Special X originally quoted for a 28 is deff where id start and id ask for that when running a piston port kit,id expect to adjust the main slightly or even needle postion but a great starting point but thats the spec i ended up with and was quoted before it was dynoed so its pretty consistant.Another example is my TS which is far from std but was kindly given a spec from Jerome even though i didnt get the carb from him and it was bang on.Again,if you wanted it finely tuned for max performance then you would need to replace a few bits but its smooth,not spluttery and ive had no issues.
As far as Piaggio having stric tolerances,maybe but im still trying to suss out how some of my mates years ago had PX125`s that were quicker than some P2`s or P2`s that could go right off the clock while others struggled to hit just over 60.

So your quite happy to say to everyone on this forum that has a piston port motor "for a 28mm Dellorto PHBH use a AV264 with X13 needle and for a 30mm dellorto PHBH use a AV266 with an X7."
My final say is........good luck everyone who follows this widespread advice on carb tuning and if you do find it goes bang because your piston port scoot needed an AV268 atomiser or X2 needle (yes Dellorto actually make 12 AV type atomisers and 8 AS type atomisers for 2 strokes and approx 30 needles, at least 5 which are known to be used on scooters X12, X7, X13 , X2 and X25) you better go and see the guys are on this thread!
It will work on a lot of motors but not all, so be warned (and this is my point).

P.S. Better tell the dealers to stop stocking other needles and atomisers as they dont need to be selling anything different to AV264, AV266 and X7 and X13. Actually maybe just add AV268 and X2 for the reed motors and thats it. No need to stock any others!

[soosh]

Depends if you have a carb finely tuned or good enough to run smooth but allow for any issues.I dont run finely tuned carbs,there is still more to get out of it but the spec i had allowed me to change the pipe,piston skirt had a trim and still fine so it is a now a different kit,not a lot but performs different.The spec Special X originally quoted for a 28 is deff where id start and id ask for that when running a piston port kit,id expect to adjust the main slightly or even needle postion but a great starting point but thats the spec i ended up with and was quoted before it was dynoed so its pretty consistant.Another example is my TS which is far from std but was kindly given a spec from Jerome even though i didnt get the carb from him and it was bang on.Again,if you wanted it finely tuned for max performance then you would need to replace a few bits but its smooth,not spluttery and ive had no issues.
As far as Piaggio having stric tolerances,maybe but im still trying to suss out how some of my mates years ago had PX125`s that were quicker than some P2`s or P2`s that could go right off the clock while others struggled to hit just over 60.

So your quite happy to say to everyone on this forum that has a piston port motor "for a 28mm Dellorto PHBH use a AV264 with X13 needle and for a 30mm dellorto PHBH use a AV266 with an X7."
My final say is........good luck everyone who follows this widespread advice on carb tuning and if you do find it goes bang because your piston port scoot needed an AV268 atomiser or X2 needle (yes Dellorto actually make 12 AV type atomisers and 8 AS type atomisers for 2 strokes and approx 30 needles, at least 5 which are known to be used on scooters X12, X7, X13 , X2 and X25) you better go and see the guys are on this thread!
It will work on a lot of motors but not all, so be warned (and this is my point).

P.S. Better tell the dealers to stop stocking other needles and atomisers as they dont need to be selling anything different to AV264, AV266 and X7 and X13. Actually maybe just add AV268 and X2 for the reed motors and thats it. No need to stock any others!

You have completely missunderstood what ive said,i would never say that that spec is final and thats it.Anyone with a brain cell or your average monkey mechanic would still tread with caution.But where do you start? Somewhere near or stick the biggest of everything in and work your way down till you have spent double the carb value and weeks up n down the road to come home to a meal for one? That 28 spec has been pretty consistent as others have used it,obviously on your iron setup with pm/jl3 it may not have been.The 30mm setup ive used a few times in the past too but again you tread with caution.Whats difficult with that? Im sorry if ive had good luck with swapping over carbs/spec from one machine to another,i`ll spec them more"on the money" next time.
I cant believe this all started because someone quoted what you should get the carb supplied with.Maybe carbs should come empty from now on.