Dellorto PHBG 21mm Carb help

Hey, just got myself one of these, but I need help as its connections etc are totally different to my current standard carb.

Would really appreicate it if somebody could tell me what connections what corresponding with the picture below.

Also, from my fuel tank I have two pipes, ones slightly larger, ones the main fuel line and i'm presuming the others the vacuum? If not what is it and where would it go?

I will also be running auto lube, so where would this connect to?

Obviously ill also need to set it up to suit my bike, so would really appreciate a basic starting point for the needle position, as I wouldn't know where to start with it, (btw is needle highest (lowest clip) the richest?) theres 4 clip positions on the needle.

And a rough jet to begin with (around 90 maybe??) And where to put the air mix screw (around 1.5 turns out?)

Also does this carb use the dellorto 5mm jets? I presume it does but not sure






1 -
2 -
3 -
4 - Idle speed
5 - Idle mix?
6 -
7 -

EDIT - ignore bit about auto lube thingy on pic, tis just a blank hole lmao.

Thanks x

 

Also would i see any benefits from removing the airbox snorkel, or will this just lose the pressure in airbox?

 

2. oil
3. fuel
4. idle speed
5. idle mix
6. vacuum
1 +7. over flow( tdr know the tecnical term for them :w00t: )

 

cheers mate, so the fuel goes in on the air inlet side, and oil after the slide on the manifold side?

ah right just over flows, fair do's, though that tbh so they need nothing.

and when you say vacuum i presume the other pipe coming from fuel tank yeah?

for some reason i had it in my head you'd be the first person to reply aha, so thanks man.

noww where to begin with jetting

 

the two connections on the manifold side just go straight into the main part (where the slide is) therefore dont pass through anything and will just go straight into the engine without going through the jets or anything,

you sure you can run auto lube on this carb?

 

That dos`nt look like a PHBG to me, that looks like a std 20.5mm 125 carb.

Does it actually say PHBG 21 on it anywhere? need clearer pics.

 

one side of the bodys got dellorto

other side says PHB6 or PHBG maybe, and has 21 just after that

i measured the body and its like 21.3mm

 

Looks nothing like this https://www.pmtuning.co.uk/Merchant...t_Code=09-PO177_0064&Category_Code=00203050K2

 

i have it in my hand, and it looks identical to that, except the idle speed adjuster and it doenst look so new

 

will a 70 main jet be too lean?

iv got a 75 on a 12mm carb and thats a tad richh.

need an answer tonight as its going on tomorrow.

also, this takes 5mm jets, and iv got 6mm ones, could i drill the hole for jets (which is currently 4.2mm internal and will be 5mm bottom of threads for the 5mm jet) could i drill it out to 5mm (6mm tapping size) and re tap in 6mm so i can use my 6mm jets?

pleaseee helppppp cause i havnt got any free time for ages after this weekend

 

i would pop a 75 MJ in their then work from their.

and just buy the right size jetbox

 

Dont drill your carb mate, just buy the proper jets.

also on your pic, aint numbers 2 and 6 the same?

 

my mate said hes got a load of jets so ill try them, na 2 and 6 are diff, they're both on the same side (mainifold side) but either side

i know what i mean LOL, theres 3 brass connections any who.

so does the oil pipe not even need to go into the carb and mix with the fuel in float bowl?

 

okay where do i connect the oil pipe (autolube) does it just mix in the the air/fuel as it goes into the engine, or shouold it mix in the flaot bowl, as if it neecs to mix in the float bowl, the only way i can see it being able to do that is to connect it to one of the overflows.

im sure lots of people have used these carbs so just need a quick answer!

ta

 

This was my Aerox project. On page 6 I asked this question, and Minor explained. have a look.

http://www.scootershack.co.uk/viewtopic ... sc&start=0

 

fuck you on about ?

put the auto lube pipe(oil) on number 2

 

its all on and conencted up now, down to a 70 jet, as wouldnt even run with an 88,

it runs okay atm, but its still not as good as it should be, theres a delay on the throttle when you blip it, however ive tried the idle mix at all sorts of positions and still no luck.

when im riding along at w.o.t if i let off, then stick the throttle back on theres a delay where nothing happenes then it will suddenly rev.

iv tried the needle on all 4 clips, and the needles currently it the lowest position (highest clip)

so erm, wtf?

x

 

might want to drop the roller weight abit with the carb aswell

 

What filter is on it? If it's the stock airbox, your supposed to modify it to allow more air through.

I had all this on the Aerox when I was setting it up. The clue was it ran really well with no airbox on at all, so it wasn't getting enough air. You could try a VERY breif run without your airbox to see if you have the same problem.

 

airbox is de-snorkelled and drilled etc already, tis modded like,

its just weird, you back off the throttle, then when you go back on the throttle nothing happens for 1-2 secs