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@johnpeterson avatar
UTC

Member
Vespa 100 Sport / PX 200 E
Joined: UTC
Posts: 8
Location: Somerset
 
Member
@johnpeterson avatar
Vespa 100 Sport / PX 200 E
Joined: UTC
Posts: 8
Location: Somerset
UTC quote
linkflageditquote
I am in the process of upgrading my Vespa 100 sport - I just want it to go at a good speed and be reliable, so I have a few questions before I spend too much on things that won't fit:

So, to move it a little quicker - a couple more CCs are needed. Perhaps a DR130 head:
https://www.sip-scootershop.com/en/product/racing-cylinder-dr-130-cc_10008000?cr=3a6304bb-cc81-4ed5-9f63-1ff45fe1abfa&gad=1&gclid=EAIaIQobChMI_6X7rqv6_gIVTKvVCh2x_w6qEAQYASABEgIBVPD_BwE

Any other options recommended?
... ... ...
I want to change the gearing from three to four - is this the best option and will I need anything else?

https://www.sip-scootershop.com/en/product/gearbox-kit-58-54-50-46-teeth-4-gear-pk_13490700?q=Gear%20Box

... ... ...
Can I get away with keeping the old carb or do I need a something like a Polini CP21?

https://www.sip-scootershop.com/en/product/carburettor-polini-cp-21-round-slider_20121030?q=Polini%20CP21%20carb

... ... ..

I suppose I will need a new exhaust - so is the Polini Snail good value?

https://www.sip-scootershop.com/en/product/racing-exhaust-polini-original-polini-evolution-cylinder_2002034R?q=Polini%20snail%20exhaust

... ... ...

Is there anything else?
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@roland87 avatar
UTC

Molto Verboso
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
 
Molto Verboso
@roland87 avatar
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
UTC quote
Not bad choice at all. Classic I'd said.

But you bit wrong with exhaust - here is what you need.
I really like this new Polini exhaust - I mount one on the customer engine and noticed how good it finished and very easy to fit.

You also need new primary - this 2.56 or this 2.54.
The main advantage of 2.56(straight cut teeth) primary is that you can buy just small cog if you realise in the future that your ratio is too long. And change it without splitting cases. On the other side primary with straight cut teeth is bit more noisy than helical one.

DR 130 is good enough with 19.19 carb and SHB carbs is very easy to setup. But bigger carb for sure give you more fun. Polini CP19 or CP21 can be mounted on original 19.19 intake manifold.

And If you go to four speed gear box your need pair of this spacers - your old spacers from three speed gear box is too thick.

IMHO: if you already go to such level of upgrades change crankshaft for sport one is good idea.
⚠️ Last edited by roland87 on UTC; edited 1 time
@chandlerman avatar
UTC

Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 79 P200E, 66 Lammy S3
Joined: UTC
Posts: 9955
Location: Nashville

71 Days Since Last Explosion
 
Lucky
@chandlerman avatar
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 79 P200E, 66 Lammy S3
Joined: UTC
Posts: 9955
Location: Nashville

71 Days Since Last Explosion
UTC quote
roland87 wrote:
On the other side primary with straight cut teeth is bit more noisy than helical one.
My smallie is my only straight-cut gear bike and I can hear no difference in the gears between it and any of my other bikes. With modern machining/finish, the relative sound difference is basically zero compared to the exhaust noise.
@roland87 avatar
UTC

Molto Verboso
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
 
Molto Verboso
@roland87 avatar
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
UTC quote
chandlerman wrote:
My smallie is my only straight-cut gear bike and I can hear no difference in the gears between it and any of my other bikes. With modern machining/finish, the relative sound difference is basically zero compared to the exhaust noise.
Just my experience.
My friends have PK's and on one is straight RMS primary while on other is helical RMS. Both have Sito Box exhausts so really quite enough and PK with straight is more noisy when run.
At the same time on my Special with much louder exhaust straight primary(Polini) sounds much louder than RMS primary on PK.
UTC

parallelogramerist
Joined: UTC
Posts: 5243
 
parallelogramerist
Joined: UTC
Posts: 5243
UTC quote
i have a 130 Parmakit touring cylinder on my PK125. It might be worth the extra $$$ to step up to an aluminum cylinder.
https://www.sip-scootershop.com/en/product/racing-cylinder-parmakit-touring-ecv-130-cc_75041920?q=parmakit%20ecv
@kourabies avatar
UTC

Hooked
125 TS VNL3
Joined: UTC
Posts: 144
Location: Greece
 
Hooked
@kourabies avatar
125 TS VNL3
Joined: UTC
Posts: 144
Location: Greece
UTC quote
sorry but because lack of time i didnt read the answers above. i thing best thing you can do is upgrade ur engine with just what a pk125 have. gears, primary, carb, cylinder etc etc and with a good exhaust i think you will have super reliable scooter! also you can check VMC aluminium cylinder kits that are vfm and VMC siluro sport banana exhaust.
i also upgraded my us special 50cc to parmakit cast iron 102 cc kit. i let it 3 speed though. i liked the idea of 3 speed
@roland87 avatar
UTC

Molto Verboso
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
 
Molto Verboso
@roland87 avatar
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
UTC quote
kourabies wrote:
sorry but because lack of time i didnt read the answers above. i thing best thing you can do is upgrade ur engine with just what a pk125 have. gears, primary, carb, cylinder etc etc and with a good exhaust i think you will have super reliable scooter! also you can check VMC aluminium cylinder kits that are vfm and VMC siluro sport banana exhaust.
i also upgraded my us special 50cc to parmakit cast iron 102 cc kit. i let it 3 speed though. i liked the idea of 3 speed
Don't forget that any of VMC kits needs much more work on casings. I have VMC GS 125 and it works really cool, but it was not cheap and long project with suitable carb, exhaust, ignition, short 4th etc.

It seems for me that topicstarter look for simple and not very expensive way of the upgrades.

On the other side there is lot of nice and powerful kits - EGIG 170 and 180 or VMC 144cc. Just get off your money.
UTC

parallelogramerist
Joined: UTC
Posts: 5243
 
parallelogramerist
Joined: UTC
Posts: 5243
UTC quote
converting a PK100 over to a 100% stock PK125XL would be rock solid upgrade. It would get you a pinch over 55mph for a top speed. Installing a short 4th would be the only mod i would consider doing. It would help with the headwinds and hills. Building
a tuned smallframe with a well balanced drivetrain (crank, carb, cylinder, clutch, variable ignition, pipe, ect) is a downward spiral of funds. Keep it stock and it will rock.
@sdjohn avatar
UTC

Johnny Two Tone
'15 GTS300, '86 PX125EFL, '66 VBB, '01 ET4
Joined: UTC
Posts: 8545
Location: San Diego, CA
 
Johnny Two Tone
@sdjohn avatar
'15 GTS300, '86 PX125EFL, '66 VBB, '01 ET4
Joined: UTC
Posts: 8545
Location: San Diego, CA
@roland87 avatar
UTC

Molto Verboso
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
 
Molto Verboso
@roland87 avatar
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
UTC quote
sdjohn wrote:
Timeless classic
@kourabies avatar
UTC

Hooked
125 TS VNL3
Joined: UTC
Posts: 144
Location: Greece
 
Hooked
@kourabies avatar
125 TS VNL3
Joined: UTC
Posts: 144
Location: Greece
UTC quote
roland87 wrote:
Don't forget that any of VMC kits needs much more work on casings. I have VMC GS 125 and it works really cool, but it was not cheap and long project with suitable carb, exhaust, ignition, short 4th etc.

It seems for me that topicstarter look for simple and not very expensive way of the upgrades.

On the other side there is lot of nice and powerful kits - EGIG 170 and 180 or VMC 144cc. Just get off your money.
in my response my opinion was to convert to pk125 engine. thats what i propose to him. i disagree with you about the vmc kits. you can put what ever kit you want with out match porting but you wont get all the power that can be gained. its up to u if you want to take full potentials of the kit. best solution of course if you are able to spend about 2-2,5k is egigs 170cc kit of course! touring and bullet proof build
@roland87 avatar
UTC

Molto Verboso
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
 
Molto Verboso
@roland87 avatar
'13 LML Star 200, '81 50 Special, '81 P 150 X, '87 PK 50 Nuova, '84 PK 50 S
Joined: UTC
Posts: 1264
Location: Ukraine. Kyiv.
UTC quote
kourabies wrote:
i disagree with you about the vmc kits.
For fitting any VMC kit you need to cut flywheel dust cover and deck the casings. Weld a bit on left side ports also not bad idea.

External inline image provided by member with no explanatory text
External inline image provided by member with no explanatory text
External inline image provided by member with no explanatory text
External inline image provided by member with no explanatory text
@kourabies avatar
UTC

Hooked
125 TS VNL3
Joined: UTC
Posts: 144
Location: Greece
 
Hooked
@kourabies avatar
125 TS VNL3
Joined: UTC
Posts: 144
Location: Greece
UTC quote
roland87 wrote:
For fitting any VMC kit you need to cut flywheel dust cover and deck the casings. Weld a bit on left side ports also not bad idea.

External inline image provided by member with no explanatory text
External inline image provided by member with no explanatory text
External inline image provided by member with no explanatory text
External inline image provided by member with no explanatory text
nice work there
@mr_fix_it avatar
UTC

Member
2021 GTS 300 Super, 1980 Vespa 100 Sport, 2009 Stella 2T
Joined: UTC
Posts: 29
Location: York, Pennsylvania
 
Member
@mr_fix_it avatar
2021 GTS 300 Super, 1980 Vespa 100 Sport, 2009 Stella 2T
Joined: UTC
Posts: 29
Location: York, Pennsylvania
UTC quote
There's helpful 100 Sport specific stuff on https://www.facebook.com/groups/174141603421991

I am really pleased with my DR130 kit, and Leo Vince exhaust. Eliminating the battery and going Alternating Current was also an excellent choice.

I kept the original 3 speed. It climbs any hill, and I'm not too worried about being fast.

https://impbarn.blogspot.com/p/vespa-100-sport-v9b1t.html

Keep us in the loop on what progress you make with your project scooter.
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