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@baba12 avatar
UTC

Molto Verboso
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
 
Molto Verboso
@baba12 avatar
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
UTC quote
So all was fine till earlier this afternoon.
When I was returning home, the engine starts fine, but doesn't want to go past 10mph. Rode across the Manhattan bridge at a mighty fast speed of 7-12mph.
When I got home and put it on the center stand, it starts fine but when I try to open the throttle up it just starts to choke.
I wonder if it is the air filter that is clogged or is it a bad fuel filter or is it a injector that has broken.
I filled up gas yesterday, so I thought it could be fuel venting issue and opened the gas cap and released any pressure if there was any and it still did not resolve the issue.
The Vespa has only 2700 miles on it. I was planning to change the engine oil this weekend, and while I am at it I will clean the air filter.
If the engine was cutting out or not idling it could be a fuel issue, and it isnt stalling. Just not wanting to throttle beyond 10-12mph at FWOT.
So I ask the wise guru's what should be the process to follow and resolve the issue(s).
@fledermaus avatar
UTC

Veni, Vidi, Posti
2007 LX150 2015 GTS (on the bench) 2017 BV 350
Joined: UTC
Posts: 11963
Location: Fond du Lac, Wisconsin
 
Veni, Vidi, Posti
@fledermaus avatar
2007 LX150 2015 GTS (on the bench) 2017 BV 350
Joined: UTC
Posts: 11963
Location: Fond du Lac, Wisconsin
UTC quote
baba12 wrote:
So all was fine till earlier this afternoon.
When I was returning home, the engine starts fine, but doesn't want to go past 10mph. Rode across the Manhattan bridge at a mighty fast speed of 7-12mph.
When I got home and put it on the center stand, it starts fine but when I try to open the throttle up it just starts to choke.
I wonder if it is the air filter that is clogged or is it a bad fuel filter or is it a injector that has broken.
I filled up gas yesterday, so I thought it could be fuel venting issue and opened the gas cap and released any pressure if there was any and it still did not resolve the issue.
The Vespa has only 2700 miles on it. I was planning to change the engine oil this weekend, and while I am at it I will clean the air filter.
If the engine was cutting out or not idling it could be a fuel issue, and it isnt stalling. Just not wanting to throttle beyond 10-12mph at FWOT.
So I ask the wise guru's what should be the process to follow and resolve the issue(s).
Can't imagine air filter problems with so few miles.

No expert on injectors, but when mine broke it was like hitting the kill switch.

Fuel may be suspect with z recent fill...
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@baba12 avatar
UTC

Molto Verboso
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
 
Molto Verboso
@baba12 avatar
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
UTC quote
Since the fillup yesterday I have put 23 miles and this issue started after mile 16/17.
I will open up the air filter and check the evap system as well. But it is weird, trying to go past 10mph made it slow down and I had to go down to like 5mph and then slowly raise the throttle and it was fine at 10mph. Luckily the traffic was horrible so I took my time getting home and did not get cursed.
@jess avatar
UTC

Petty Tyrant
0:7 And counting
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Location: Bay Area, California
 
Petty Tyrant
@jess avatar
0:7 And counting
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Location: Bay Area, California
UTC quote
It's almost never the air filter.
UTC

Hooked
2013 BV350, 2014 GTS , 2016 GTS, 2013 Downtown 300i, 2018 Like 150i
Joined: UTC
Posts: 402
Location: Dahlonega, GA
 
Hooked
2013 BV350, 2014 GTS , 2016 GTS, 2013 Downtown 300i, 2018 Like 150i
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Posts: 402
Location: Dahlonega, GA
UTC quote
jess wrote:
It's almost never the air filter.
Truth
@burt37 avatar
UTC

Addicted
GTS 300 SS BB
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Location: QLD AUS
 
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UTC quote
Pure guess...

Either the front or the rear pickup sensor for the ABS/traction control is either dirty with metal particle or broken...
@attila avatar
UTC

Veni, Vidi, Posti
In garage: Yamaha Tricity 155 Urban 2019 - MV Agusta 125 RS 1956
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Location: Latina (Italy)
 
Veni, Vidi, Posti
@attila avatar
In garage: Yamaha Tricity 155 Urban 2019 - MV Agusta 125 RS 1956
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UTC quote
...blame the gasoline ...
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@baba12 avatar
UTC

Molto Verboso
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
 
Molto Verboso
@baba12 avatar
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
UTC quote
Burt37 wrote:
Pure guess...

Either the front or the rear pickup sensor for the ABS/traction control is either dirty with metal particle or broken...
Will investigate that. There was a "click, click" sound one could hear from the front wheel that was loud when it got to 10-12mph but would fade away once it was below 7mph or so. It sounded like something was stuck to the tire and everytime it came around was hitting a fixed point and causing that sound. I thought it was a piece of plastic that may have got stuck to the wheel.
Will report back later today.
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@baba12 avatar
UTC

Molto Verboso
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
 
Molto Verboso
@baba12 avatar
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UTC quote
Update on this issue.
Checked the Vespa rear tire this morning and find there is a nice screw in the tire & the tire is now flat.
I am guessing this maybe the cause for the throttle not revving cuz the ABS speed sensor is messed up as suggested by Burt37.
Now question is do i remove the rear wheel and get a new tire put or do I fix the flat with a rope puncture kit in situ and then see the throttle rev issue is resolved or not.
Is a flat tire repair kit just a temporary solution, or does one leave it in there till it is time to replace the tire?
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@berto avatar
UTC

Molto Verboso
2006 LX150 (carbed) | 2007 GT200
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Location: Toronto
 
Molto Verboso
@berto avatar
2006 LX150 (carbed) | 2007 GT200
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Location: Toronto
UTC quote
baba12 wrote:
Update on this issue.
Checked the Vespa rear tire this morning and find there is a nice screw in the tire & the tire is now flat.
I am guessing this maybe the cause for the throttle not revving cuz the ABS speed sensor is messed up as suggested by Burt37.
Now question is do i remove the rear wheel and get a new tire put or do I fix the flat with a rope puncture kit in situ and then see the throttle rev issue is resolved or not.
Is a flat tire repair kit just a temporary solution, or does one leave it in there till it is time to replace the tire?
Good find!

I think fixing with a rope plug makes a lot of sense to make sure the problem is solved.

Whether that rope plug is a permanent fix depends on your risk tolerance. You will get lots of opinions.

If that were my tire, I'd remove it and mushroom plug from the inside.

But I know many people would just replace it (shops here won't plug or patch a motorcycle tire, for example). Still others would roll on the rope plug until the tire was worn.
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GTS 300 SS BB
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UTC quote
baba12 wrote:
Update on this issue.
Checked the Vespa rear tire this morning and find there is a nice screw in the tire & the tire is now flat.
I am guessing this maybe the cause for the throttle not revving cuz the ABS speed sensor is messed up as suggested by Burt37.
Now question is do i remove the rear wheel and get a new tire put or do I fix the flat with a rope puncture kit in situ and then see the throttle rev issue is resolved or not.
Is a flat tire repair kit just a temporary solution, or does one leave it in there till it is time to replace the tire?
Being in the rear, I would try first to remove the screw and use one of those tyre repair kit. See if it holds the pressure, so not to trigger the traction control issue again and then replace the tyre later on when required..
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@baba12 avatar
UTC

Molto Verboso
2018 Vespa 300 GTS Touring
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Posts: 1349
Location: NYC
 
Molto Verboso
@baba12 avatar
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
UTC quote
The hope is that the tire puncture is the issue and the throttle will rev up again, and nothing else. If it is resolved then the goal is to get the plug to work temporarily till I source a new tire and replace it.
I am guessing that once the flat is fixed temporarily I will have to recalibrate the ABS/ASR system even though I am not removing the wheel off.
I will find out from a couple of places here (not the Vespa dealership) but others like Scooter Bottega what the charges would be to mount a new tire if I brought it to them versus buying a tire and getting mounted by them.
Will post an update later tomorrow.
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GTS 300 SS BB
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UTC quote
baba12 wrote:
The hope is that the tire puncture is the issue and the throttle will rev up again, and nothing else. If it is resolved then the goal is to get the plug to work temporarily till I source a new tire and replace it.
I am guessing that once the flat is fixed temporarily I will have to recalibrate the ABS/ASR system even though I am not removing the wheel off.
I will find out from a couple of places here (not the Vespa dealership) but others like Scooter Bottega what the charges would be to mount a new tire if I brought it to them versus buying a tire and getting mounted by them.
Will post an update later tomorrow.
Do you remember seeing the red light in the dashboard when the engine was not revving?
I don't believe you will have to recalibrate the ASR as long both wheels are of similar circumference..

You can do a test to see if the light and the ASR is working correctly..

Put the bike on the centre stand start the engine, let it warm up for few seconds then accelerate. You should see the red light and unable to accelerate...
Try then to turn the ASR off and see if you can accelerate...
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@baba12 avatar
UTC

Molto Verboso
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
 
Molto Verboso
@baba12 avatar
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
UTC quote
I dont remember seeing the red light, but Ill test this suggestion and report back. I hope to work on the Vespa tomorrow early in the day and shall have some answers thereafter. Thank you.
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Banned
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Location: Canton, MI
 
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UTC quote
Te exact same thing happened to me a few weeks back. At 40mph, the rear end of bike wobbled and I immediately lost acceleration. The ASR light came on and I had just enough power to pull off into a parking lot. My rear tire was completely flat. Thankfully an automotive repair shop was very close by and I was able to walk it over and the owner let me store the bike in his garage overnight. I went back the next morning and plugged the tire and was able to get it home. Now, my scoot has two new Michelin City Crip 2's.
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@baba12 avatar
UTC

Molto Verboso
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
 
Molto Verboso
@baba12 avatar
2018 Vespa 300 GTS Touring
Joined: UTC
Posts: 1349
Location: NYC
UTC quote
Rare that I get to complete the task that I say I am going to do. I plugged the puncture, it was a screw that was about an inch and a quarter. Filled up air to 37psi, sprayed some dishwashing liquid(that I dilute and keep in a spray bottle to wash my dishes with), no bubbles were noticed.
Turned the engine on, it revs fine but I am not sure if ABS needs recalibration as I turned it off to see how it worked. Going to take it for a short spin and see if it behaves ok if not Ill recalibrate and see.
For sure I would not have concluded that this issue was a function of a flat tire. If not for the valuable knowledge shared by the members of this forum I'd have been going down the wrong street. Thank you and will report back after the short quick spin how it went.
If it is all good then the goal will be to get a new set of tires, will have to check with the shops if they would mount the wheels if the tires aren't bought from them, if not find out what it will cost to get the tire replaced.
Update:- Took it for a test ride and it worked smooth as before. Will take it for a longer ride later and see how it works. Have to do fluid changes and clean the air filter, has to be done during the week.
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