Sun Nov 20, 2022 6:12 pm

Lurker
P125x
Joined: 20 Nov 2022
Posts: 4
Location: Skagit
 
Lurker
P125x
Joined: 20 Nov 2022
Posts: 4
Location: Skagit
Sun Nov 20, 2022 6:12 pm linkquote
Hello ,I'm new and know very little. I got this bike a while ago.but never ride it.i did not build this. Has about 100 miles give or take on it.i believe it has this setup...
Pinasco 166 aluminum head(where are markings)
Phbh 28
Reed intake
Jl pipe
Ducati blue cdi
High flow fuel tap
Cut crank(?not sure)
Air filter directly to vespa outlet of frame.

Ok,, so it runs decent I have only 2 main jets a 105 and another which is definitely bigger but number is unreadable.(I will be buying more jets)
My eyes can't read the needle size but it seems ok.
OK. I don't want to seize this bike. The FUEL mix screw is almost impossible to get to.but I have it 2.5 turns out. I am using the main jet with the unreadable number. I tried my needle clip on various notches. I am now on the top notch. Goes through all gears fine but seems to run lean. I have no puff of 2 stroke smoke out pipe. It is very strong in power ban.scary strong. I don't ride it cuz I haven't ordered main jets yet.
QUESTION. IS IT OK to ride it on top needle notch? It's the leanest setting but rides the best and wicked strong on that setting. Can I seize due to needle position??
Or can I just adjust fuel mix screw out more and do a plug chop?
What would you do?
If I set needle on the second notch down it's rideable but not like it is now on first notch which is wicked great but seems lean.
Again I don't want to seize this.
What is the average turns out of the fuel screw mix for this.? I started at 2 out and went to 2.5 for good measure
Thanks for the input. I'm concerned about needle position. I need input on safety from seize.
Sun Nov 20, 2022 11:25 pm

Lurker
P125x
Joined: 20 Nov 2022
Posts: 4
Location: Skagit
 
Lurker
P125x
Joined: 20 Nov 2022
Posts: 4
Location: Skagit
Sun Nov 20, 2022 11:25 pm linkquote
Anyone??
Sun Nov 20, 2022 11:58 pm

Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 4420
Location: That bushfire place
 
Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 4420
Location: That bushfire place
Sun Nov 20, 2022 11:58 pm linkquote
The biggest problem is main jet size, or lack there of. 105 is TINY

Not much we will be able to help with, unless you let us know all the parts inside the carb.

Needle position is no worries once you know the rest of the setup
Phones have good zoom for photos of jets etc.
Mon Nov 21, 2022 12:00 am

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 12200
Location: The state of insanity, SoCal
 
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 12200
Location: The state of insanity, SoCal
Mon Nov 21, 2022 12:00 am linkquote
I would confirm ALL of your parameters: kit, crank, compression, inlet timing, profiled head, transfer/exhaust timing, ignition timing FIRST so you know what you're working with.

then CONFIRM the carb set up- jets, needle, diffuser, slide

anything else is just a guess, really. so I guess it could run safely if you dropped clip and bumped up the A/F mix screw and checked your ignition timing.

or I guess it could lock up tighter than a bull's ass at fly time hauling 65mph down a two lane.
Mon Nov 21, 2022 3:42 am

Addicted
Joined: 28 May 2020
Posts: 603
Location: Planet Earth
 
Addicted
Joined: 28 May 2020
Posts: 603
Location: Planet Earth
Mon Nov 21, 2022 3:42 am linkquote
SubEtherBASS wrote:
The biggest problem is main jet size, or lack there of. 105 is TINY

Not much we will be able to help with, unless you let us know all the parts inside the carb.

Needle position is no worries once you know the rest of the setup
Phones have good zoom for photos of jets etc.
https://www.scooter-center.com/en/tuning-set-for-carburettor-bgm-pro-dellorto-phbh-28-phbh-30-main-jets-130-135-idle-jets-58-60-atomiser-as266-needles-x3-x7-x13-bgm8549
Mon Nov 21, 2022 10:35 am

Lurker
P125x
Joined: 20 Nov 2022
Posts: 4
Location: Skagit
 
Lurker
P125x
Joined: 20 Nov 2022
Posts: 4
Location: Skagit
Mon Nov 21, 2022 10:35 am linkquote
Thanks. Hey greasy when you say drop clip you mean down a notch? Quest #1On a newer kit can I starve fuel with the needle position and seize.or is it more based on mixture screw?#2 is there a good tutorial on timing checks. I'm not experienced. Another words I've never checked timing on vespa.#3 Where is the stamp on cylinder for what kit it is??
Also I'm not using the 105 jet. The one I'm using is crappy and where the number is it flaked and is no longer readable.so I'm using one that I happened to find just to run it.its bigger than a 105.
This was originally setup by someone that is a good mechanic and that this forum seems to respect. So I'm assuming he set timing correctly. Just a assumption.
So let's say all is good. #4What would the fuel mixture screw turned out to be on a rough average. I know it depends but a ball park? **and I just never read on here about that needle position being at top notch. Most seem to be at 2nd to top. #5Would you drop it down a notch??
I was a bit all over the place on this post so I obviously tried to find order by numbering questions. Small ancient phone. Thanks
Mon Nov 21, 2022 1:08 pm

Jet Eye Master
PX221 MHR, O tuned PX200, PX181 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3528
Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX181 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3528
Location: London UK
Mon Nov 21, 2022 1:08 pm linkquote
ferriswolf wrote:
https://www.scooter-center.com/en/tuning-set-for-carburettor-bgm-pro-dellorto-phbh-28-phbh-30-main-jets-130-135-idle-jets-58-60-atomiser-as266-needles-x3-x7-x13-bgm8549
Can't believe how cheap this jet kit is. Buy this and the answer is in there.
Mon Nov 21, 2022 3:54 pm

Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 4420
Location: That bushfire place
 
Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 4420
Location: That bushfire place
Mon Nov 21, 2022 3:54 pm linkquote
Sounds like time for you to do a bit of learni...

Read this & the Dellorto PHBH links... Then you may start to understand why we are requesting some helpful info!
Ponderings on jetting

Old Malossi 221 with PHBH 28 needs to be richer at cruising

This is a MUST READ & UNDERSTAND before you will get things sorted...
http://www.iwt.com.au/private/Dellorto%20manual.pdf
Wed Nov 23, 2022 11:38 am

Lurker
P125x
Joined: 20 Nov 2022
Posts: 4
Location: Skagit
 
Lurker
P125x
Joined: 20 Nov 2022
Posts: 4
Location: Skagit
Wed Nov 23, 2022 11:38 am linkquote
Thanks . I'll read all and order jet kit. Again it runs fine I just was more concerned
About needle clip at very top. Less fuel more lean but if compensating with fuel mix screw will work then I'll do that. Yep I've alot to learn
I looked up that kit. I'd believe the main jets are too big. I was wanting 115-125
Wed Nov 23, 2022 6:41 pm

Molto Verboso
PX 200
Joined: 25 May 2016
Posts: 1110

 
Molto Verboso
PX 200
Joined: 25 May 2016
Posts: 1110

Wed Nov 23, 2022 6:41 pm linkquote
You're gonna be going around in circles.

You really need to confirm a few things like Greasy said.

Most important in my experience are:
- leak down test (not compression test)
- squish
- correct ignition timing

Those 3 things have the biggest impact on jetting for the same engine.

If those aren't followed up properly, you'll never jet the carb correct ever.

The fuel mixture screw on a PHBH helps dial in machining tolerances and isn't really to compensate for smaller or larger jets. Generally it's 1.5 turns out or 3.5 turns out depending on the engine setup, and the jets have to match the engine.

You can see, as you turn the fuel mix screw move out from the hole on the intake side of the carb. It's not a mysterious number.

For your setup (PX Reed valve engine), should be 1.5 turns out and the needle should be 2nd clip from the top (unless you're in the mountains, then maybe top clip).

Most Vespa engines will be on the second clip, just seems to be the best for the needle taper to kick in.

You should be looking at running a x2 needle and as264 or 266 atomiser, depending on altitude, air temperature, humidity.

But honestly nothing will work properly if the 1st 3 points are not correct. It's just how the engine runs, basic physics maybe.
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