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Vespa gt 125 main jet prediction....
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@pecker avatar
pecker
UTC
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GT 125 (03), PX 166 (99) S3 (66) Imola 186
Joined: UTC
Posts: 45
Location: Nr Exeter Devon UK
 
pecker
Member
@pecker avatar
GT 125 (03), PX 166 (99) S3 (66) Imola 186
Joined: UTC
Posts: 45
Location: Nr Exeter Devon UK
UTC quote
Hello everyone,....
Could I please have your predictions regarding main jet when using a malossi double red sponge filter in partnership with doing the air box mods please...

Sip recommends upping 5-10 sizes for the filter (in there catalogue,.. but only mentions upjetting the regular filter on line) a little confusing ???

Would anyone like to predict allowances for air box mod ???

Are starting point is 98 MJ.....
All the best
Pek,...
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Motovista
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Veni, Vidi, Posti
GT 200
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Posts: 9465
Location: Main Street, Watts
 
Motovista
Veni, Vidi, Posti
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GT 200
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Posts: 9465
Location: Main Street, Watts
UTC quote
No change
OP
@pecker avatar
pecker
UTC
Member
GT 125 (03), PX 166 (99) S3 (66) Imola 186
Joined: UTC
Posts: 45
Location: Nr Exeter Devon UK
 
pecker
Member
@pecker avatar
GT 125 (03), PX 166 (99) S3 (66) Imola 186
Joined: UTC
Posts: 45
Location: Nr Exeter Devon UK
UTC quote
Runs terribly, only allowing to rev to just below half throttle around 40 mph, so have had to cover air box up so engine revs out somewhere correctly ???
Any other ideas...
Pek
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bluecloud
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Ossessionato
2018 GTS Super
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Location: Googleville
 
bluecloud
Ossessionato
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2018 GTS Super
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Posts: 2564
Location: Googleville
UTC quote
pecker wrote:
Any other ideas...
Yeah, put the airbox back to stock, Malossi sponge is fine, but any other mods won't work with factory CV carb.
OP
@pecker avatar
pecker
UTC
Member
GT 125 (03), PX 166 (99) S3 (66) Imola 186
Joined: UTC
Posts: 45
Location: Nr Exeter Devon UK
 
pecker
Member
@pecker avatar
GT 125 (03), PX 166 (99) S3 (66) Imola 186
Joined: UTC
Posts: 45
Location: Nr Exeter Devon UK
UTC quote
Thankyou,.. for the responses,
Yes covering it up / going back to normal has cured it,

I did read somewhere on the air box mod thread that someone said it should/may be possible to use air box mod in a carbed GT ..??? by upping the main jet,
think he had some success with a GT 200,...
I've tried a 108 mj so as said using mod may be out of question ....

All the best
pek
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