Lambretta 'breathing problem'

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Scootermonkey
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Any ideas on this one guys? Lambretta, 175 top end, 42mm clubman, 22mm carb. Starts first go from cold but quickly starts choking itself. Take the air hose off, runs sweet as a nut! Put the rubber back on and it dies. Clear airway through hose and air filter box/scoop. Even removed the filter element. Tried three Jetex carbs, one brand new and was running perfect on another scooter. Tried a brand new Scootopia carb, tried and tested on yet another scooter. Think I've tried every jet/slide combination, still no joy. Starting to annoy me now. Never had this problem before. Any help appreciated
How hard can it be!
Lambretta, the finest scooter............IN THE WORLD!
Knowledge
Dealer
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Joined: Sun Jan 11, 2009 12:49 am
Main scooter: GP
Location: Ipswich
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Is the restrict or still in the air scoop under the seat? If in doubt, remove the air scoop but keep the air box, just in case it is the air scoop (though this is usually an issue when running at mid to high revs)
Martin
Muppet
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Main scooter: SX 150 running in

try changing the air box for a GP one
C’est la vie
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Scootermonkey
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Changed the airbox and scoop for a S3 one, not even using a filter element. Airways completely clear
How hard can it be!
Lambretta, the finest scooter............IN THE WORLD!
Chris in Margate
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Main scooter: Lambretta 1964 225 Special
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Suddenly happened, slowly got worse, or always been like it ?
bristolmod
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Main scooter: Lambretta TV175 S3- what else!
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air hose weak and collapses under load? Try another air hose.

Chris
Scootering since 1968.
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EddieStone
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Main scooter: Lambretta Li 150
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Is the choke cable/mech working properly. I'm wondering if the choke is still open a little bit, if the cable is tight or something?
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Scootermonkey
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Engine just had a full rebuild. So first time running. Seems to want to cut out as soon as the rubber hose goes near the carb. But will start easy from cold. Runs 30 seconds and bogs down and wwants to die
How hard can it be!
Lambretta, the finest scooter............IN THE WORLD!
LeightonRB20
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As Bristolmod says; air hose collapsing. A problem with some Asian imported parts. Try another one that you know works.
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Scootermonkey
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The rubber is brand new, but I'll check it anyway. Cheers
How hard can it be!
Lambretta, the finest scooter............IN THE WORLD!
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