OP
UTC

Lurker
Vespa Primavera 50 4t 4v
Joined: UTC
Posts: 1
Location: Montreal
 
Lurker
Vespa Primavera 50 4t 4v
Joined: UTC
Posts: 1
Location: Montreal
UTC quote
It only has 2000km on the odometre. Here's the issue :
It would start fine
It idles ok
Then I can drive it for a while, but every time I release the gas, when I throttle it back, it responds late.
Eventually, after driving for a while, when I release the throttle, the gas doesn't quit respond, and it eventually stalls.
Then it takes a few kick to start it again. I think I found that opening the gas cap and putting it back on helps it start again. Then it goes fine
Also,at the first start, If I give gas, it will idle at a lower speed after each throttle, until a good push of gas makes it stall wen released.
Any idea what the problem could be ?
@jimc avatar
UTC

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43890
Location: Pleasant Hill, CA
 
Moderaptor
@jimc avatar
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43890
Location: Pleasant Hill, CA
UTC quote
If opening the gas cap helps, then almost certainly the problem is a clogged evap charcoal canister. This can easily happen if you have, even just once, over-filled the tank.

The symptoms should disappear in time as the liquid gradually evaporates, but if it were my bike I'd remove the Evap Crap immediately.
@kaukari avatar
UTC

Hooked
GTS 300 ABS, 2018
Joined: UTC
Posts: 176
Location: Finland
 
Hooked
@kaukari avatar
GTS 300 ABS, 2018
Joined: UTC
Posts: 176
Location: Finland
UTC quote
Too much fuel too little air...?
First. If it is a new fuel injected model you should not give it any gas when started. It will wet the sparkplug and bike will not run well.

If it is a carburator model, you may run with too rich mixture. Your air filter may be clogged or your automatic choke is not working and stays on all the time.

Look at your sparkplug. If it is black and wet after ride, we are on to something. Also checking and cleaning the air filter is never wrong.
@jimc avatar
UTC

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43890
Location: Pleasant Hill, CA
 
Moderaptor
@jimc avatar
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43890
Location: Pleasant Hill, CA
UTC quote
Re: Too much fuel too little air...?
kaukari wrote:
First. If it is a new fuel injected model you should not give it any gas when started. It will wet the sparkplug and bike will not run well.

If it is a carburator model, you may run with too rich mixture. Your air filter may be clogged or your automatic choke is not working and stays on all the time.

Look at your sparkplug. If it is black and wet after ride, we are on to something. Also checking and cleaning the air filter is never wrong.
The symptoms are of fuel starvation, not the opposite. All down to the tank vent that's via a roll-over valve and a charcoal canister being clogged. You may not be familiar with the Evap Crap in Finland.
@kaukari avatar
UTC

Hooked
GTS 300 ABS, 2018
Joined: UTC
Posts: 176
Location: Finland
 
Hooked
@kaukari avatar
GTS 300 ABS, 2018
Joined: UTC
Posts: 176
Location: Finland
UTC quote
True
The Evap is a mystery to me. Would be the first item to delete at least from my Vespa.
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