Sun Sep 11, 2022 11:51 am

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Sun Sep 11, 2022 11:51 am linkquote
Hi there!
I'm really don't wanted to start this thread as I thought that I can figure out all by myself.

But I can't.
I hope someone can help me with right jetting.

Prehistory:
P150X not matching ports with DR 177 and Malossi cylinder head.
Rotary intake
SI 24/24 E drilled 2.5mm: AC 160 - BE3 -125 MJ and 55/160 idle.
Original air filter with drilled holes above jets
Mazzucchelli racing crankshaft 57mm stroke
22/68 primary
SIP Road 2 exhaust
SIP Touren flywheel 1.6 KG
SIP fast flow fuel tap.

I ride on that setup near 7000 miles short in town and really long hard runs on the mountain roads. Everything was fine, plug colour is right, I can easily hold 55-57 MPH for a really long time and temperature holds on 275-285º F.

Then I change exhaust for Polini Box and like it more than old despite I lost 2-3 miles of max speed. Still runs perfect without any other changes.

And then I put new SIP T5 air filter and Polini carb case cover. Run for a long stretch and I see that the temperature is growing faster and already at 50 MPH it easily reach 300ºF and continues grow up. Obviously jetting is too lean.

Then I change idle jet for 50/140 and main jet for 128. But it seems that it not helps really.
So its time to play with air corrector and mixer tube?
I don't understand anything at all, please help me understand. Maybe there is some links where I can read about SI carb settings? TIA.







Sun Sep 11, 2022 12:20 pm

Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1447
Location: California
 
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1447
Location: California
Sun Sep 11, 2022 12:20 pm linkquote
I keep saying how good this filter and carb top are!

The Air Corrector is the air jet this will determine how much air can enter the emulsion tube. Popular trend is run this at 120 which is the least amount of air.

The atomizer is going to tune the low and mid range power. Popular trend is run this as rich as possible. I'm running the leanest so find which runs the best. I like factory smooth.
Sun Sep 11, 2022 12:32 pm

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Sun Sep 11, 2022 12:32 pm linkquote
hibbert wrote:
I like factory smooth
Tried my friend's all original PX125 and really like how smoot is it run. With Polini exhaust, Polini carb case cover and T5 air filter my P become much smoother than it was before.
Sun Sep 11, 2022 12:48 pm

Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1447
Location: California
 
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1447
Location: California
Sun Sep 11, 2022 12:48 pm linkquote
Start with a 120AC this will richen things up. I tried a 110AC but went back to the 120.

You can try a larger mixer and see how that does. It's going to be some trial and error to find the best recipe. Think the higher temps could indicate better air flow with new filter. How does it feel?
Sun Sep 11, 2022 1:03 pm

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Sun Sep 11, 2022 1:03 pm linkquote
I really like how scoot runs after all changes. Much more smoother and and more responsive to the throttle. Polini exhaust is also quieter than Road 2. Less vibrations and gets to 60 mph quicker.
Tue Sep 20, 2022 10:09 am

Jet Eye Master
PX221 MHR, O tuned PX200, PX181 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3454
Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX181 Quattrini and some motorbikes
Joined: 14 Jun 2017
Posts: 3454
Location: London UK
Tue Sep 20, 2022 10:09 am linkquote
AC120/BE4 and work from there. Usually about 115
It will be quicker once jetted better. With the polini exhaust it would pull a 23/68.
Tue Sep 20, 2022 1:13 pm

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Tue Sep 20, 2022 1:13 pm linkquote
Jack221 wrote:
AC120/BE4 and work from there. Usually about 115
It will be quicker once jetted better. With the polini exhaust it would pull a 23/68.
Thanks a lot for advice, Jack!
Already ordered AC120, 140 and BE4. Now need to order some main jets as the smallest I have is only 118.
Wed Sep 21, 2022 11:23 pm

Addicted
Joined: 28 May 2020
Posts: 574
Location: Planet Earth
 
Addicted
Joined: 28 May 2020
Posts: 574
Location: Planet Earth
Wed Sep 21, 2022 11:23 pm linkquote
roland87 wrote:
I really like how scoot runs after all changes. Much more smoother and and more responsive to the throttle. Polini exhaust is also quieter than Road 2. Less vibrations and gets to 60 mph quicker.
Is it a real 60mph though? I had the polini on my DR177 and it was so disappointing top end. The road 2.0 will pee all over it top end and easily get to 110KHM indicated on speedo, , which in reality is about 64mph GPS. The polini could barely reach indicated 100 kmh, often it would hover about 95kmh and thats a big drop. I tried so hard to like the polini, i mean its great for local riding, two up, yes its quieter, but had to go back to the road 2.0, tried polini twice using all sorts of different tweaks but i could get no more blood out of that stone so road 2.0 back on.
Wed Sep 21, 2022 11:52 pm

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Wed Sep 21, 2022 11:52 pm linkquote
ferriswolf wrote:
Yes Ferris, I think its real 60 MPH. I measured lot of times with my smartphone app and with GPS speedo. I also have sip speedo so I adjusted it for have same results as on my phone app.
And yes - with Road 2 top speed was near 105-108 KMH but I very rarely ride with that speed as there is a lot vibrations and it seems that engine soon blow down.
With Polini top speed is 102 KMH and never more. But I really likes how this pipe works and power delivers.
Thu Sep 22, 2022 1:10 am

Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1862
Location: UK (South East)
 
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1862
Location: UK (South East)
Thu Sep 22, 2022 1:10 am linkquote
Comparing your spec. with mine:

You
P150X not matching ports with DR 177 and Malossi cylinder head.
Rotary intake
SI 24/24 E drilled 2.5mm: AC 160 - BE3 -125 MJ and 55/160 idle.
Original air filter with drilled holes above jets
Mazzucchelli racing crankshaft 57mm stroke
22/68 primary
SIP Road 2 exhaust
SIP Touren flywheel 1.6 KG
SIP fast flow fuel tap


Me
PX150 with ports enlarged, matched DR 177, cylinder raised 1.0mm
VMC Super G cylinder head.
Rotary intake (inlet enlarged)
SI 24/24 E drilled 2.5mm: AC 120 - BE4 -115 MJ and 52/140 idle.
Venturi (OopsClunkThud/Shapeways) and stock autolube box top
Jasil racing crankshaft 57mm stroke
23/68 primary
BGM BigBox Touring exhaust
Stock flywheel 2.2 KG
BGM fast flow fuel tap

Very similar setups, although I have done some porting/enlarging/matching and raised the cylinder for better port timings. For a DR177, it has really good power and ~62 mph/100 kmh top speed. It is very solid and reliable.

I agree with others that AC120 and BE4 is the way to go, especially with a venturi, or in your case a T5 filter and increased air box volume. Also, if you have the power, the 23T clutch is a good move to get the best top speed.
Thu Sep 22, 2022 1:38 am

Addicted
Joined: 28 May 2020
Posts: 574
Location: Planet Earth
 
Addicted
Joined: 28 May 2020
Posts: 574
Location: Planet Earth
Thu Sep 22, 2022 1:38 am linkquote
roland87 wrote:
Yes Ferris, I think its real 60 MPH. I measured lot of times with my smartphone app and with GPS speedo. I also have sip speedo so I adjusted it for have same results as on my phone app.
And yes - with Road 2 top speed was near 105-108 KMH but I very rarely ride with that speed as there is a lot vibrations and it seems that engine soon blow down.
With Polini top speed is 102 KMH and never more. But I really likes how this pipe works and power delivers.
The DR is a very vibratey noisy kit. When mine first went on I seriously thought there was something wrong with it. Have you noticed on start up how rattly they sound, then when it heats up it calms down considerably. I was getting some vibration with my setup and also with the polini box. Since rethinking all of the jetting with some advice and me experimenting , the vibration is a lot less and 60mph gps with the road 2.0 is so much better. I upped main jet from 122 to 124, changed the air filter to have smaller drill holes above main and pilot; this made driving so much better so my vibration must be due to being a tad too lean. Just found it hard going from road 2 to polinibox, i so wanted to like the polini but the lack of top end frustration for dual carriageway overtakes was annoying.
Thu Sep 22, 2022 5:10 am

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Thu Sep 22, 2022 5:10 am linkquote
swa45 wrote:
I agree with others that AC120 and BE4 is the way to go, especially with a venturi, or in your case a T5 filter and increased air box volume. Also, if you have the power, the 23T clutch is a good move to get the best top speed.
Thanks for the tip Swa. I tried 23T clutch before I put on Malossi head and T5 filter with Polini carb cover. It was good on highways but terrible in town use, esp. when changing 3rd to 4th gear. Terrible lack of power on 4th or need rev really high on 3rd.

I'm really thinking to put short 4th gear when I need next time to open cases.
But I also have old 6 springs clutch with 23T cog. So when I will end sort the carb settings I try put again 23T. If it will be ok then I will be order 23T for my Cosa clutch.
ferriswolf wrote:
The DR is a very vibratey noisy kit. When mine first went on I seriously thought there was something wrong with it. Have you noticed on start up how rattly they sound, then when it heats up it calms down considerably.
Yes I noticed it and was very confused when start engine at first time. But now already done more than 12000 km on this engine with no mercy to it on long highway trips or on mountain roads and it still feels ok. So I think its really good reliable kit.



Thu Sep 22, 2022 5:38 am

Addicted
Joined: 28 May 2020
Posts: 574
Location: Planet Earth
 
Addicted
Joined: 28 May 2020
Posts: 574
Location: Planet Earth
Thu Sep 22, 2022 5:38 am linkquote
roland87 wrote:
Thanks for the tip Swa. I tried 23T clutch before I put on Malossi head and T5 filter with Polini carb cover. It was good on highways but terrible in town use, esp. when changing 3rd to 4th gear. Terrible lack of power on 4th or need rev really high on 3rd.

I'm really thinking to put short 4th gear when I need next time to open cases.
But I also have old 6 springs clutch with 23T cog. So when I will end sort the carb settings I try put again 23T. If it will be ok then I will be order 23T for my Cosa clutch.



Yes I noticed it and was very confused when start engine at first time. But now already done more than 12000 km on this engine with no mercy to it on long highway trips or on mountain roads and it still feels ok. So I think its really good reliable kit.
Definitely reliable , It's my daily work horse . Not that exciting but a good performance boost over standard 125/150.
Thu Sep 22, 2022 6:33 am

Hooked
125 GTR 1977, 50S 1975, GTS 125 Supertech 2021
Joined: 04 Aug 2014
Posts: 226
Location: Madeira Island
 
Hooked
125 GTR 1977, 50S 1975, GTS 125 Supertech 2021
Joined: 04 Aug 2014
Posts: 226
Location: Madeira Island
Thu Sep 22, 2022 6:33 am linkquote
I'm not adding much for what have been said, but, why did you felt the need to fit the SIP T5 air filter and the bigger carb case from Polini? It seems it was riding fine with the Polini box only loosing those 2-3 miles of top speed ... which is what I would expect changing the SR2 to the Polini box.

SIP tested (YT video) a bunch of box exhausts on dyno and the Polini delivered more power on low/mid revs and less in high revs than the SR2, hence the lost on top speed.
Thu Sep 22, 2022 12:13 pm

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Thu Sep 22, 2022 12:13 pm linkquote
The price on the T5 filter and carb cover was so good that I could not refuse. Also mesh on my original air filter is torn in few places and I already thought about buying new filter.

So as my order with AC and mixer tube is still on the way I decide to try bit richer idle jet.
Swapped today 50/140 for 52/140. Tomorrow will see how it goes.



Fri Sep 23, 2022 1:26 am

Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1862
Location: UK (South East)
 
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1862
Location: UK (South East)
Fri Sep 23, 2022 1:26 am linkquote
roland87 wrote:
Thanks for the tip Swa. I tried 23T clutch before I put on Malossi head and T5 filter with Polini carb cover. It was good on highways but terrible in town use, esp. when changing 3rd to 4th gear. Terrible lack of power on 4th or need rev really high on 3rd.

I'm really thinking to put short 4th gear when I need next time to open cases.
But I also have old 6 springs clutch with 23T cog. So when I will end sort the carb settings I try put again 23T. If it will be ok then I will be order 23T for my Cosa clutch.
Yes, like I said, IF you have the power

I do not know about the older P150X gearbox, but my late PX150 has the same gearbox as a PX200, but with 68T primary. Therefore, I have a 35T 4th gear and a BIG gap from 3rd. Mine is ok with the 23T clutch, but I did consider a 36T clutch gear like the PX125.
Fri Sep 23, 2022 2:39 am

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Fri Sep 23, 2022 2:39 am linkquote
The only what I remember for sure when I opened cases is that my gearbox have 68T cush drive cog and 35T 4th gear sprocket.
And this is not EFL gearbox with old type of cruciform.
And my P is VLX1T 337318 and motor is VLX1M 339705 so it 1981.
It also was with points 12V Ducati ignition.

But now I confused what exactly I gearbox I have according to this https://drive.google.com/file/d/1riP6fNWz424xY6KW31QrH-w2uwnwAwA_/view?usp=sharing
Tue Sep 27, 2022 4:00 am

Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1862
Location: UK (South East)
 
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1862
Location: UK (South East)
Tue Sep 27, 2022 4:00 am linkquote
swa45 wrote:
Me
PX150 with ports enlarged, matched DR 177, cylinder raised 1.0mm
VMC Super G cylinder head.
Rotary intake (inlet enlarged)
SI 24/24 E drilled 2.5mm: AC 140 - BE5 -125 MJ and 48/140 idle.
Venturi (OopsClunkThud/Shapeways) and stock autolube box top
Jasil racing crankshaft 57mm stroke
23/68 primary
BGM BigBox Touring exhaust
Stock flywheel 2.2 KG
BGM fast flow fuel tap

Just for the record, my jetting was very different to what I remembered from 2020. I ran my PX150/DR177 into London at the weekend with my wife as pillion. Sixty mile round trip with a 15 mile stretch of motorway in each direction. The scoot performed really well and showed 105 km/h on the speedo for at least 10 miles. It made me realise that the DR may be old skool, but it's still a great kit
Tue Sep 27, 2022 4:17 am

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Tue Sep 27, 2022 4:17 am linkquote
Thanks for input mate.
Wed Sep 28, 2022 12:03 pm

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Wed Sep 28, 2022 12:03 pm linkquote
Today I received pair of AC(120 & 140) and mixer tube BE4.

Now it's noticeably colder. In the morning temperature is 8ºC(46ºF).
And now on my way to work engine temperature is less and seems not so scary as when there was more warm weather.

Nevertheless I changed the main jet stack to:
AC 120
Mix BE4
Main Jet 118
Also changed idle jet back to 50/140(2.8) as with 52/140(2.69) spark plug looks too black.

I made small test run and was impressed and confused how scoot is accelerating now. Really much better than with old jets.

On next three photos is spark plug colour(as camera distorts in reality colour is more dark) with:
Polini Box exhaust
Polini carb cover
SIP T5 air filter
AC 160 mix BE3 mj 128 ij 52/140

There was near 12ºC(53ºF)

And for comparison on last two photos is spark plug colour with old set up:
SIP Road 2 exhaust
Original low carb cover
Original 20/20 drilled air filter
AC 160 mix BE3 mj 125 ij 55/160

There was near +25ºC(77ºF)


AC 160 mix BE3 mj 128 ij 52/140


AC 160 mix BE3 mj 128 ij 52/140


AC 160 mix BE3 mj 128 ij 52/140




AC 160 mix BE3 mj 125 ij 55/160

Wed Sep 28, 2022 1:12 pm

Veni, Vidi, Posti
'15 GTS300, '86 PX125EFL, '66 VBB, '04 Ninja 250
Joined: 04 Apr 2013
Posts: 6525
Location: San Diego, CA
 
Veni, Vidi, Posti
'15 GTS300, '86 PX125EFL, '66 VBB, '04 Ninja 250
Joined: 04 Apr 2013
Posts: 6525
Location: San Diego, CA
Wed Sep 28, 2022 1:12 pm linkquote
No photos with 120ac?
Thu Sep 29, 2022 12:06 am

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Thu Sep 29, 2022 12:06 am linkquote
sdjohn wrote:
No photos with 120ac?
No photos yet. Just installed it yesterday evening. And this morning make near 40km on my way to work.
Scoot runs great.
But temperature is still too high as for me. I hold 85 km/h for maybe 5-6 km on highway and temp easily gets to 150ºC(302ºF) outboard temperature is just 10ºC.

Now thinking about what jet I need change to richer - idle or main?
Thu Sep 29, 2022 11:55 am

Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
 
Hooked
'81 Special, '81 P150X, '87 PK50 Nuova '13 LML Star 200
Joined: 30 Nov 2018
Posts: 217
Location: Ukraine. Kyiv.
Thu Sep 29, 2022 11:55 am linkquote
Ride a bit but not enough for sure with this jetting:

AC 120
Mix BE4
Main Jet 118
Idle Jet 50/140(2.8)

And noticed that temperature grows much faster when I on WOT than when I holds near 85 km/h it a little bit less than 1/2 open throttle.

I also decide to mark throttle grip and change MJ to 122. Hope tomorrow I can ride enough to understand more.



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