Piaggio Typhoon 4t 4v 80cc

[vermi]

Hi, i'm from Montreal, Quebec, Canada

Last year i buy (used) a Piaggio Typhhon 50 2013 4 stroke 4 valve, stock top speed was 42~45 mph.
In acceleration they are fast, fast like a 2 stroke motor, the Piaggio motor have 4 valves.
This model come with a 20mm carburetor, pilot jet #35 and main jet #72.

This spring in install a Malossi 80cc kit, with the CDI and gears ratio.
Rejet the main at #75 and everything was fine...
The acceleration it's very fast and strong and top speed on GPS 85KM\H (52Mph) no wind and flat road.

Last week i buy a new exhaust, the TECNIGAS GP4. The dealer said i just need to install and nothing else to do.
But the first ride, in deceleration it make some baskfire , PFFFT sound and popping... Popping is ok for me but backfire i don't want that!!!
I check the manifold, no leaking, i plays with the gas mixture on the cvk carburetor (2 turns open), nothing realy change.
I try pilot jet #38, no change but bad acceleration and weird idling... Reinstall # 35.

Yesterday i change the main jet for a #78, I see a good difference in acceleration, less backfire but when motor come hot after 20 minutes the backfire are loud sometime.!

I do not want hear backfire in deceleration next to a policeman on the street, why i try to found the problem....

do you have an idea

Thank's for help!

[tito]

I was watching a video today on carb tuning and he said you get backfires from the idle jet being too rich, also I could have sworn Ive read you have to change the idle jet as well when you install a big bore kit. Im sure an experienced builder will add more but that could be a start.

[vermi]

Problem solved!
I installed the original carburetor KEIHIN NCV 20, with brand new pilot jet #35 and main jet #78.
No more popping or back fire after a long ride of 1 hour on long road and stop and go!  On a long road  i hit Top speed 51 mph on my GPS.
I'm happy now!
Thank's your advice!

[branko]

Hello Vermi,

I have the same scooter as yours, Typhoon 50 4t 4v usa modell (I live in Europa) with less than 1000 km .

So, in stock max speed was ca 70 km/h (fast to 60...little slower to 65...and sloooower to 70) and because it was dangereus in traffic

...decision ...go make some stronger and faster.

I am not interesting for bigger 150,200cc, 50cc is ok and fun for me.

Installation ;Pollini kit 80cc 49mm, gear secundar Malossi HTQ 15/55,kevlar belt Malossi,variomat Pollini Hi speed, Malossi cdi, main jet 75...the rest stock.

The result...great !

Increasing of speed linearrrr....fast to 60,fast to 70,little slower to 80 and max after some period to 90.

We will see what would be in a future, but for now everything is more than ok.

Do you have any question, proposal ...your opinion...?

P.S. new fly 50 4t 4v was restricted to 45 km/h and only with malossi cdi 70 km/h (very similar as usa typhoon...obviously different in cdi).

[aeroxbud]

Oct 21, 2021 15:35:00 GMT -5 branko said:

Hello Vermi,

I have the same scooter as yours, Typhoon 50 4t 4v usa modell (I live in Europa) with less than 1000 km .

So, in stock max speed was ca 70 km/h (fast to 60...little slower to 65...and sloooower to 70) and because it was dangereus in traffic

...decision ...go make some stronger and faster.

I am not interesting for bigger 150,200cc, 50cc is ok and fun for me.

Installation ;Pollini kit 80cc 49mm, gear secundar Malossi HTQ 15/55,kevlar belt Malossi,variomat Pollini Hi speed, Malossi cdi, main jet 75...the rest stock.

The result...great !

Increasing of speed linearrrr....fast to 60,fast to 70,little slower to 80 and max after some period to 90.

We will see what would be in a future, but for now everything is more than ok.

Do you have any question, proposal ...your opinion...?

P.S. new fly 50 4t 4v was restricted to 45 km/h and only with malossi cdi 70 km/h (very similar as usa typhoon...obviously different in cdi).

Welcome to the forum.
I have a 2019 typhoon. They are a nice looking bike. But mine is a two stroke.

[scooter7878]

U would keep going up one main at a time. Whatever jet gives u the highest rpm and speed use that one or one Richer. U don't know those scooters directly but 78 sounds a bit small for a 80cc. But whatever motor whatever jet gives u the most rpm at wot in the same stretch of road is the proper jet that system works good Ive used it for years and it's always very close to spot on I've jetted that way than checked it with a air fuel ratio sensor and it was spot in in proper ratio.