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21mm PHBG carb help

R

RAW

Well-Known Member
OK need some help
My scoot which has lots of mods mainly a 70cc Malossi kit.No gears as up till today I can not get any to fit the Hyosung SF50.

Anyway I pulled the carb off to find out what jet and metering rod we installed.( after I pulled the restrictor out of the Yasuni R) Now the scoot has some up and down power burst in the idel to 1/4 throttle.Then it falls flat almost stalls right out. Pull out the throttle and it will stay running.

Ok I have the carb off what do you think should be in it for a jet and rod.

Then i will say what is in it now.I have never been able to say this thing goes.Heck over the last year i have riden it 3 weeks due to the build at the shop which went all wrong.

Forgot I am pre mixing at 40 to 1 with Amsoil

Anyway ?
Thanks
 
Last edited:
OK it the carb has a 74 jet and a W7 rod.
And to refreash
On a 70cc with no gears Dopplar filter.
 
Your running way too lean. You need to go up some 10-15 jet sizes. Put the clip of the needle in the middle. Turn the air/fuel ratio screw aprox. 2 turns out from the bottom end and apply a 90MJ.
 
I was thinking of it running lean.I have not pulled the plug yet I will tomorrow( well today).
Like I said with the exhaust Yasuni R still having the restrictions in it when they installed it and set it up that is why it also was a slug.

I also noticed last thing this evening that I have now a idle ping.

OK tomorrow i will go on the hunt for a few jets but I am going to order a jet and rod kit tonight.

So you think a 82-85 would be a good start and use the W7 rod.
 
On my NRG (MHR Replica LC, Dellorto 19 PHBG on airbox with 20mm intake, Yasuni R):

Needlejet 262AU
Needle W7 (2. position)
idle jet 50
Throttle valve 40
main jet 84


For PHBG 21, you need aprox. 90-92 mainjet if other parts are the same
 
Thanks for the reply.
I am running a Hyosung (O) SF50
Malossi 70cc,Custom intake manifold,Malossi reeds,Dopplar filter,No gears,

I never checked the idle jet yesterday I will today.
With my scoot I had a nightmare of mods done I will save it as I posted it in the project section.A shop did the work over 6 months and handed it to me running.That was it not set up.
So I have been trying to get going as next month will be 1 year I have had this scoot in 2 shops and i have only rode it less than 30 days.
I am looking today for some jets local but as well will order a jet pack.
 
Does your atomiser look like this.



Or like this



I ask because i just found out on Dellorto site the lower one is for 2 strokes and the upper is for 4 stroke.

And I have the upper one installed in my carb
 
Yes I am getting that as well, I emailed Dellorto direct to ask what atomiser I should oder to start with as I will have to switch from the 4 stroke atomiser to the 2 stroke atomiser.

Man nothing shocks me with the shop mistakes they made on my scoot I find one or 2 a day it seams.
 
you need the rod wich has au262 on it
with a w16 needle and stationairyjet 50 thats a small jet
main jet must be between 85/100
but the au262 rod doesnt fit because you need the gold colored thing what is in the center
of the carburator where you put the rod in
 
I had several emails this am with Matt from Dellorto.
He said the atomiser is not a issue as both styles can be used on the 2 strokes with no issues.

So the atomiser is solved.
He recommended a 90-110 jet with the W7 rod as a starting point.I asked about the W6 and W16 with no reply on those questions.I asked as i can not find any spot local or in Canada to get the parts so i ordered a Stage6 jet kit but will need to order the rods and a few spare parts from Dellorto.(rod clip after spending 30 minutes on my knees looking for it after I dropped it) so I got a few extra at .60 each.
 
your enigie gets with the an262 rod a very low mixture on topspeed and if you take a bigger main jet it wil run bad in the beginning of your power.
it wil run very rich
i have tested it on the stage 6 racers because the an 262rod is in the dell o black standard and it was not very good if you want that your enigine runs very good
use the au262
on this forum there is a guy that can deliver you that stuf his name is rainman he is from denmark and he is distrubutor of dell o goodluck
 

Thanks but the au262 rod you are talking about is infact a atomiser not a rod.
Were you talking about the atomiser and change from the au260 which I have installed now and go to the au262 atomiser or were you talking about a jet and got the number wrong.
Thanks for the help.
Last night I ordered these direct from Dellorto
W6 Needle
Idle jet size 55
Needle circlip - small
Idle jet size 52
Needle circlip - small
1486 jet size 93
W16 Needle
 
RAW said:
Will do with the Dellorto parts and the Stage6 jet kit I will get it going.

Hope so
Click to expand...
Please don't forget that you will need to get the matching copper (coloured) threaded bushing which is pressed into the carburettor to screw in the AU atomizer when you don't have an AU type atomizer at the moment.

AFAIK these don't have a regular Dell'Orto part number, so they are kinda hard to get.
 
Last edited:
Yes Matt from Dellorto said the insert would need to be replaced.But his recommendations was to us the atomiser that was in my carb and see how that works first. So I ordered all the parts less the atomiser and the insert like you mentioned. See how long the parts take to arrive direct from Dellort.
 
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