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PHBL 26mm jetting starting point

Posted: Sun Jun 01, 2014 5:03 pm
by Monty
Guys. After all the problems I have had with timing and carb spitback Im giving up with my 22mm Jetex. I still want to go through the airbox as I don't like that induction Blaah.
I can buy a 26mm carb at a reasonable price but if I want it jetting for my setup its an extra 100 quid. and thats just a starting point.I am steering away from a bloody big carb as economy is also a factor. I have an Imola that drinks Petrol for England and while its fun I can watch and here the petrol go down
SO my friends
Muggy 185 latest spec? Bridged inlet, JL Snail, 26mm PHBL through a modified airbox and GP inlet scoop
Not run this kind of carb before any one running one who can give me a heads up on needles and mains

Re: PHBL 26mm jetting starting point

Posted: Sun Jun 01, 2014 9:17 pm
by Donnie
25 phbl or 26phbh?

Re: PHBL 26mm jetting starting point

Posted: Sun Jun 01, 2014 10:12 pm
by scootcoot
Try X7 needle , mid clip, AV266 atomiser , 105 main jet , airscrew 2 turns out , had this set up on a muggy 186 with ram filter and jl3 and ran fine but as always its only a starting point .. ;)

Re: PHBL 26mm jetting starting point

Posted: Mon Jun 02, 2014 6:03 am
by Monty
Donnie wrote:25 phbl or 26phbh?
You are correct mate a 26phbh NS I dont really know the difference.
Also seen several atomiser recommended eg AV268. Any info on how the range works weaker richer same with needles. I know they have 3 or 4 slots and you can move them up or down but does lowering the needle make it leaner or richer. If you started with an x7 and needed to go further is at as easy as a an x6 or x8? Thanks Dellorto virgin :oops:

Re: PHBL 26mm jetting starting point

Posted: Mon Jun 02, 2014 10:03 am
by warts
Needles being tapered, by lowering it (putting the clip in a higher groove) you have a thicker bit of needle in the jet = less area to flow fuel = weaker mixture.

Re: PHBL 26mm jetting starting point

Posted: Mon Jun 02, 2014 11:25 am
by Donnie
Bristol Lambretta club has some good stuff on this http://www.bristollambretta.com/dellort ... eedles.htm

Re: PHBL 26mm jetting starting point

Posted: Wed Jun 04, 2014 6:52 pm
by Monty
OK Im a sucker for ebay... I know.
My win turned up today and seems fine BUT I have an extra jet next to the choke, very small and unmarked Is this a powerjet? Does this make any big difference to jetting?
The atomizer is a 262FD so I presume this will need changing?
It also has a a 35 slide and a 60 choke.
Im not too worried about buying new needles and jets as I will need to get a collection together just wondering about the extra jet

Re: PHBL 26mm jetting starting point

Posted: Thu Jun 05, 2014 2:49 am
by corrado
If you started with an x7 and needed to go further is at as easy as a an x6 or x8? Thanks Dellorto virgin :oops:
Carb manufacturers wouldn't dream of making things that simple, they like to shuffle the deck. X7, X13, X2 are the 3 common ones on a PHBH Lambretta set up.

Start rich and work your way leaner with the help of plug checks.

Start lean and keep buying new pistons.

Re: PHBL 26mm jetting starting point

Posted: Thu Jun 05, 2014 11:21 am
by Monty
Its the buying of pistons im trying to avoid lol.
What are the implications of the power jet if thats what it is. Its a 2nd brass jet next to the choke jet. Very small about 3mm in diameter. It seems fixed and has no markings I can see. Would I be better useing it or can it be blanked off for easier setting up

Re: PHBL 26mm jetting starting point

Posted: Thu Jun 05, 2014 1:06 pm
by corrado
I'm not familiar with a PHBH NS carb? Normal PHBH for use on a Lambretta is PHBH BS. They don't come with power jets.
262 FD atomiser sounds strange too, normal use ones would be AV264 and AV266, normal slide would be a 40.
It might even be a 4 stroke carb if you've bought it blind off fleabay.

My Imola ran a Mikuni TMX27 carb and it did over 50 mpg and I rarely spared the revs.