Power loss at full throttle
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Member
Lx 50 2T 2012
Joined: 06 Oct 2020
Posts: 7
Location: Cyprus
Tue Oct 06, 2020 6:32 am quote
When I open the throttle at the last 1/6 of it it just stops pulling and power cuts off, if I let the throttle a bit less the power comes back. So I cant hit the full power which is bummer when riding a 50. Is this a problem with the main jet? Thanks!
(Vespa lx 50 2T 2012)
Addicted
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 526
Location: Deepinnaharta, Texas
Tue Oct 06, 2020 6:38 am quote
Greetings:

Yes furl need at wide-open throttle is managed by the main jet, and needle retracted from it. The question is WHY? Did this symptom just appear recently? I could also imagine a worn belt allowing the engine to over-rev and this would invoke the electronics to prevent engine damage. A cheap tach would answer the question.
Member
Lx 50 2T 2012
Joined: 06 Oct 2020
Posts: 7
Location: Cyprus
Tue Oct 06, 2020 7:14 am quote
Wheelman-111 wrote:
Greetings:

Yes furl need at wide-open throttle is managed by the main jet, and needle retracted from it. The question is WHY? Did this symptom just appear recently? I could also imagine a worn belt allowing the engine to over-rev and this would invoke the electronics to prevent engine damage. A cheap tach would answer the question.
Its like that since the day I bought it, just got a tiny bit worse. Just to give you an idea when give it full throttle it sounds like there are tiny metal balls in my engine and its revving pretty high. Thats my best way of describing it. So what do you suggest?
Member
Lx 50 2T 2012
Joined: 06 Oct 2020
Posts: 7
Location: Cyprus
Tue Oct 06, 2020 7:15 am quote
Wheelman-111 wrote:
Greetings:

Yes furl need at wide-open throttle is managed by the main jet, and needle retracted from it. The question is WHY? Did this symptom just appear recently? I could also imagine a worn belt allowing the engine to over-rev and this would invoke the electronics to prevent engine damage. A cheap tach would answer the question.
Also top speed was 4-5 kmh more two months ago, now im struggling to hit 70
Addicted
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 526
Location: Deepinnaharta, Texas
Tue Oct 06, 2020 7:25 am quote
Greetings:

Start with a look at the spark plug? Perform a compression test while the hole is open.
Member
Lx 50 2T 2012
Joined: 06 Oct 2020
Posts: 7
Location: Cyprus
Tue Oct 06, 2020 11:22 am quote
Wheelman-111 wrote:
Greetings:

Start with a look at the spark plug? Perform a compression test while the hole is open.
Ok ill check it out, I see you windsurf and Im a windsurfer myself. Where do you sail?
Ossessionato
2016 Vespa GTS300ie abs/asr/ess Settantesimo '70'
Joined: 11 Jun 2011
Posts: 3033
Location: East Anglia, a dryer region of the UK than Israel
Tue Oct 06, 2020 11:51 am quote
Have you got a rev limiter on that thing? It does sound as if you are over revving it. Two strokes tend to destroy themselves very nicely if over revved on a regular basis. So to stop that, many cdi units will retard the ignition and then drop the spark momentarily. Just thinking that may be happening. A motor can achieve full power without the throttle being fully open at the grip.
Member
Lx 50 2T 2012
Joined: 06 Oct 2020
Posts: 7
Location: Cyprus
Wed Oct 14, 2020 11:37 am quote
Stromrider wrote:
Have you got a rev limiter on that thing? It does sound as if you are over revving it. Two strokes tend to destroy themselves very nicely if over revved on a regular basis. So to stop that, many cdi units will retard the ignition and then drop the spark momentarily. Just thinking that may be happening. A motor can achieve full power without the throttle being fully open at the grip.
You must be right about over revving, it does sound like that. So, giving less throttle to just hit powerband and keep it rolling like that is the answer?
Addicted
2010 S50 Modified "Punkin"; 2003 ET4 150 "ISO"
Joined: 18 Feb 2017
Posts: 526
Location: Deepinnaharta, Texas
Wed Oct 14, 2020 2:53 pm quote
Greetings:

Unable to use full throttle?! HERESY, I tell you. I for one would not stand for it!
A better answer is to find out WHY your engine exceeds maximum RPM before it reaches top speed. Worn belt is Suspect #1. If you have modified the powerplant in any way, it may be necessary to change the final drive gearing for "Taller" or numerically Lower cogs.
Member
Lx 50 2T 2012
Joined: 06 Oct 2020
Posts: 7
Location: Cyprus
Wed Oct 14, 2020 3:41 pm quote
Wheelman-111 wrote:
Greetings:

Unable to use full throttle?! HERESY, I tell you. I for one would not stand for it!
A better answer is to find out WHY your engine exceeds maximum RPM before it reaches top speed. Worn belt is Suspect #1. If you have modified the powerplant in any way, it may be necessary to change the final drive gearing for "Taller" or numerically Lower cogs.
Ill go have checked out by my mechanic, Im thinking about installing a multivar malossi
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