dellorto

flybytaco

flybytaco

Metal Molding Madman
anybody use a dellorto phbg15? i just picked one up to see if some gains can be made.
 
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heres a pic of it while checking jets
P1013049.jpg

P1013050.jpg

and one with intake
P1013047.jpg
 
I have one. i have not yet been able to tune it properly b/c i keep having to wait for jets so i cant tell if there are performance gains or not.

there is apparently a whole science to tuning it so i can not tell you if i have noticed any power gains yet.
THIS IS WHAT IVE LEARNED:
There's a real science to tuning these things. Y ou start with the idle circuit and work your way up the throttle range to WOT. At each range start rich an go leaner.
this site helps:
http://www.mopedarmy.com/wiki/How_To_Tune_PHBG_Carburetors#Functions_of_Jets_and_Needles

THIS IS WHAT I HAVE:
grubee skyhawk "80cc", manic mechanic h/c head, long exhaust and muffler,
15mm dellorto PHGB carb
it has consistently run too rich at idle. The stock idle jet was a "50" and i am now down to a "38" and its still too rich. i am now waiting for smaller jets.
As far as i can tell im doing everything right... ill pass on what i learn. I'm also willing to take advice on tuning these things.
 
I use 18mm phbg.

You will need to change the needle to like a w12 or w23 i think.

There fatter thicker needles.

Also need to run a smaller idle jet.

An for mainjet somewhere around 85 to 90.

I believe have settled for the W12 needle. I'll have to check my carb.
Before i changed the needle it was running wayy wayy too rich.
 
you may have the AN atomizer, you need the AU. AN is for 4 strokes, which will make it real rich at idle.

what intake is that? the phbg has the bigger i.d.
 
what intake? mine? it has the atomizer for the 2 stroke too the intake is jims cns inny fits the dellorto mint
 
here's what ive got so far:

pirate cycles billet intake
atomizer:262 AU (2-stroke)
idle jet:38-still too rich...decent throttle response but four strokes a lot...cant get it to idle without opening throttle to 1/8-1/4 (should have enough air with slide juuusssst open. it doesnt)...choke kills it...plug black

untuned as yet (must get idle set first):
main jet:70
needle: W7
slide: #40

:-||
 
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black start engine warm it up a few and try turning the air screw in or out with the throttle at about 1/8th turn you will either hear it clean up or hear it start to load up. you really need the ear for tuning lol i have the 50 pilot jet in it with the clip on needle on top leanes position with the 70 main and it idles incredible. the air screw makes a huge diffrence where it idles
 
mine is a mix screw (on motor side of slide) start with is @ 2.5 turns from bottomed out and adjust from there. turning it in leans out the mix. i kept doing so looking for the sweet spot and it bottomed out.
http://www.mopedarmy.com/wiki/How_To_Tune_PHBG_Carburetors#Functions_of_Jets_and_Needles
According to the tuning manual, main jet,clip,needles and slide do not come into play at idle. it says if the idle jet is not properly adjusted, you will not be able to tweak the others properly and you'll be chasing your tail.
does anyone see another way to interpret the "manual"?
 
black do you have the carb with the pull choke the setup where u see that oring or a cable actuated like the setup to the left of it? that oring is under the choke button when you unscrew it off the carb it wouldnt be on the cable actuated model.
 
Cable actuated...ur right. There doesn't seem to b one on that model. Dak to the drawing board.....I'm now trying to adjust the main first. Down to a 66 and still rich....will advise. So far the CNS has it over performance of the dellorto
 
yea i was wondering why u were saying you have the fuel screw . mine has an air screw and the pull choke knob. put try a 50 55 main
 
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