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hazbaz |
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hazbaz Derestricted Danger
Joined: 25 Mar 2023 Karma :
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Posted: 20:17 - 25 Mar 2023 Post subject: Vespa ET4 - Starts at FULL throttle |
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Hello,
Vespa ET4 125 Pre-Leader/Mikuni BS Carb
Been chasing some issues with the scoot today.
Have done some work (see below), and now the bike starts at FULL throttle! Throttle cable isn’t sticking. Throttle is closed at carb. Have made sure that the throttle body is properly seated in intake, so pretty sure there’s no air leaks. Idle screw is an issue, as I don’t understand how it works (what it does on the carb), and I’m sure it’s set wrong, but changing it doesn’t seem to effect the throttle. Could something be stuck open in the carb? What is the most likely source of this? TIA.
Drained all the E10 out of it, replaced fuel tap, line and vacuum hose with new. Filled with E5 premium. Should make it happier.
Removed carb, dismantled, checked it all over. Very clean, looks like it was serviced not long before I bought it. Put it back together and then back on scoot. Did a compression test beforehand, 230 PSI. Nice healthy engine.
Changed out fuel contaminated oil for new. |
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Nobby the Bastard |
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Nobby the Bastard Harley Gaydar
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hazbaz |
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hazbaz Derestricted Danger
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Nobby the Bastard |
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Nobby the Bastard Harley Gaydar
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hazbaz |
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hazbaz Derestricted Danger
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to v or not to v |
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to v or not to v World Chat Champion
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WD Forte |
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WD Forte World Chat Champion
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that_impulse_guy |
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that_impulse_guy Nitrous Nuisance
Joined: 07 Mar 2023 Karma :
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Posted: 22:55 - 25 Mar 2023 Post subject: Re: Vespa ET4 - Starts at FULL throttle |
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hazbaz wrote: | Have made sure that the throttle body is properly seated in intake, |
I need this explained. .. are you saying the round bit of the carb in sitting nicely inside the rubber bit of the airbox/rubber bit of the engine intake?
in which case go check if you have the slide wrong way round.
The slide typically has a groove in it and a corresponding pin, so it can only fit in properly one way. If it is turned around the other way, then that would match your symptoms 100%
https://www.vintagebikebuilder.com/uploads/1/6/9/1/16913922/slide-2_orig.jpg
https://www.vintagebikebuilder.com/uploads/1/6/9/1/16913922/slide-align_orig.jpg ____________________ Gone: Yamaha DT50lc, Suzuki DR500, Suzuki A100, Kawasaki z250ltd, RD350YPVS, Suzuki DR Big, Kawasaki AR125, Kawasaki KMX200, Suzuki GS1000S, Katana 1100, GS550M, Suzuki RGV250
Now: Suzuki GSX400X, Suzuki RF900R, NS400R |
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that_impulse_guy |
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that_impulse_guy Nitrous Nuisance
Joined: 07 Mar 2023 Karma :
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Posted: 23:05 - 25 Mar 2023 Post subject: |
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in case its not clear, the "cutaway part", faces the airbox/air intake...the pictures above may not necessarily match your slide, but its a slide with the same grooves and stuff, so representative. ____________________ Gone: Yamaha DT50lc, Suzuki DR500, Suzuki A100, Kawasaki z250ltd, RD350YPVS, Suzuki DR Big, Kawasaki AR125, Kawasaki KMX200, Suzuki GS1000S, Katana 1100, GS550M, Suzuki RGV250
Now: Suzuki GSX400X, Suzuki RF900R, NS400R |
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hazbaz |
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hazbaz Derestricted Danger
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hazbaz |
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hazbaz Derestricted Danger
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Bhud World Chat Champion
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hazbaz |
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hazbaz Derestricted Danger
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Pete. |
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Pete. Super Spammer
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Posted: 06:28 - 26 Mar 2023 Post subject: Re: Vespa ET4 - Starts at FULL throttle |
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It's a CV carb, the throttle cable works a butterfly so it doesn't have a slide with an idle cutaway. ____________________ a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good |
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Easy-X Super Spammer
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Nobby the Bastard |
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Nobby the Bastard Harley Gaydar
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Nobby the Bastard |
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Nobby the Bastard Harley Gaydar
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Old Thread Alert!
The last post was made 1 year, 32 days ago. Instead of replying here, would creating a new thread be more useful? |
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