QUATTRINI M1XL

Anything related to Vespas... ask tech questions, post helpful info, or just read and learn.
gadgetman
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The more power you make the more heat you produce so everything has to be optimum in the cooling dept unfortunately the inlet manifold acts as a restriction to the air coming from the fan slightly reducing the amount of air circulating around the barrel. On short runs its not enough to cause a problem but on long ones the heat build up gradually rises. I cured it by fabricating an air scoop to increse the flow.. you will need a fuel pump as well plus dont think your carb will clear the frame . An air folter is definitely required.
GLscoot
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Main scooter: Vespa GS150
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On the air issue, I was thinking of putting louvers on the side panel, but couldn't find any one to do the work. Or you could do what LML have done on there autos, just a thought. Or add the air scoop that has been suggested.
Image
Vespa GS GS150 Ulma Air Scoop by GLscoot, on Flickr

This is a half scoop, you can make a full scoop for the vents.
Gary
cartmel808
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Main scooter: 1975 Vespa Rally 200 Femsa
Location: Durham, England
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gadgetman wrote:The more power you make the more heat you produce so everything has to be optimum in the cooling dept unfortunately the inlet manifold acts as a restriction to the air coming from the fan slightly reducing the amount of air circulating around the barrel. On short runs its not enough to cause a problem but on long ones the heat build up gradually rises. I cured it by fabricating an air scoop to increse the flow.. you will need a fuel pump as well plus dont think your carb will clear the frame . An air folter is definitely required.
Cheers for the info.... Do you have any pictures of the air scoop you've fabricated?
Also - which air filer & fuel pump are you using on yours?
TBH - I thought I might have gotten away with just a fast flow tap, and didn't really want to complicate things by adding a pump.. :?
gadgetman
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The fuel pump ive got pumps fuel up onto a small header tank where it is gravity fed back down to the carb. Its quite a thirsty engine so just in the process of fitting an ss90 style reserve tank which will take the capacity up to about 16 litres. As regards the air scoop it fits directly to the flywheel housing and according to the cylinder head temp guage has made a big difference especially on the blasts down the motorway.
GLscoot
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Can you post a picture of the header tank and where did you get it from, how many banjos are there in the header tank, I've been told to have three, feed, out & feed back to tank. Im beginning to hope I don't need one. The last time I used the scooter it was fine on long journeys but short and up hills fcking hopeless coughing & spluttering all the way. Im hoping this set up will work.
Image
IMG_2539 by GLscoot, on Flickr
gadgetman
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Header tank from Chiselspeed yes it has an inlet from the diaphragm pump. An outlet which runs down to the carb. And another outlet which takes the surplus back to the tank. Similar to a modern fuel injected car in that fuel is constantly flowing from tank to engine and back again. As for a photo the header is fitted in the frame right under the front of the seat where the hinge is so not visible to take a picture. The system works perfectly with no need for flow restrictors in the fuel line that you need with the alternative direct fuel pump to carb system
GLscoot
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What would you say the volume of the header tank is, and does it need to be gravity fed from the header or can the feed from the header to the carb be below the carb. Where is your fuel pump sitting, on the engine similar to the one in the picture above.
Cheers Gary
gadgetman
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Vol of header tank only needs to be small about a quarter of a litre. Yes it needs to be above the carb to work as it is supposed to work otherwise you may as well have the carb directly fed from the pump. The beauty of this system is the carb float valve has a more accurate control of the petrol flow rather than it fluctuating due to fuel pressure . As for the position of the pump provided its spmewhere below the petrol tap ot doesn't matter .if I was any good at posting photos on here one picture would show how it works. If you get chance to come to Camping in Catcliffe in about 8 weeks time you can have a look at my scooter.
OzOAP
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Main scooter: Vespa PTS1E
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A reasonable size inline filter, between pump and carb, acts as a good 'swirl pot' and reduces pulsing to carb.
GLscoot
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Wheres Catcliff ?
I am hoping I don't need to fit the pump, but from the description from the posts I should be able to work it all out. My big problem is space, its going in the GS project on the forum. Im hoping it fill fit above the petrol tap door. Couple more things, the header tank where do you get them from, the ones I see are all weird and wonderful shapes and does the fuel pump need to sit horizontal or can it sit at an angle.

Oh & sorry for hijacking your thread cartmel808, I hope you have some benefit from my questions. Anyway how is the build coming along. Still love to see that exhaust on the scooter.

Cheers Gary
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