IMG_3976 by [url=https://flic.kr/p/qjrPxo]IMG_3975 [/url]IMG_3977 [/url]IMG_3988 by [url=https://flic.kr/p/qvq5r1]IMG_3987 [/url]IMG_3982
I have just bought a after market cylinder barrel for the GS150, I knew it would not be great and my suspicions were proven correct. But I wasn't buying it for a restoration, my plans were to use the barrel and get the scooter engineers to do there magic and fit a modern manifold and carburettor straight on to the barrel, like the original GS150. I won't be going any bigger than a 24mm dellorto or similar on the carb, the piston bore is 58.7mm. I wasn't going to change anything else as its not that easy, if pushed I could install a better exhaust. Your thoughts.
Clutch 22/26 teeth
Primary Drive/Xmas Tree 12/16/20/24/67 teeth
Gear Cogs
1. 58th 11mmX118mm (approx measuremeant)
2. 54th 9mmX111mm
3. 50th 9mmX102mm
4. 46th 9mmX94mm
If I went down the Quattrini road, would that be to powerful for the rest of the engine and does anyone have a Quattrini base gasket so I can see how much would need to be removed from the original GS casings. I know it has been done before, in Italy but there is no information other than a 40second video on Youtube and the engine is on a stand.
cheers Gary
Can This Be Done to a GS150 or fit Quattrini
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It is an option, but I feel the original carburettor will not be up to it due to its age and the wear & tare of the parts. I know you can get most parts for the carburettor including slide, jets & float chamber. I also know you can get the carb body honed to take a larger slide again another option. I would just like to know if there are other options out there where I can keep the engine as original as possible and only use remade parts.fastfrog wrote:Why don't you just tune the original barrel. Lots of HP are hidden in this nice 2 port/piston ported cylinder.
Engine Casings are more available than original barrels and carburettors.
No experience in this tune: But looking at the evidence I would follow Fasfrog's approach with an altered inlet manifold with appropriate rubber and carb of your choice (PHBL?): Reasoning = the Clutch capacity and lack of ready exhaust options.
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That was my plans for the remade barrel, open that up and fit a reed valve, just not sure how much work can be done on the barrel. As for the exhaust, there is an American company who make a performance exhaust with all the correct attachments. I was also thinking that I could change the threaded section on the barrel by getting it turned to accept a standard Vespa exhaust or add the large nut to a standard exhaust and keep the threaded attachment on the barrel.Yanker wrote:No experience in this tune: But looking at the evidence I would follow Fasfrog's approach with an altered inlet manifold with appropriate rubber and carb of your choice (PHBL?): Reasoning = the Clutch capacity and lack of ready exhaust options.
The GS clutch has a strengthened band welded to the basket, so I think that might be ok. I was more worried about the actual gear change as the selector is not the strongest part.
I am hoping the tuning shops would have a look to see what can be done to the barrel and how easy it would be to change it to a reed valve set up, similar to the Quattrini.
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Be worth speaking Sean Bradey @ Scooterotica Gary... he built my quattrini motor (amongst others) and is a vespa tuning guru & an all round top bloke... and SIP sell gasket sets for the Quattrini m1xl http://www.sip-scootershop.com/en/produ ... +_15045400
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Right this could be very interesting to see if a Quattrini reed block (or any other one) could fit with a small amount of work on this barrel. best way to get a 2 main/2 boost port system. A rocket thereafter.....GLscoot wrote:That was my plans for the remade barrel, open that up and fit a reed valve, just not sure how much work can be done on the barrel. As for the exhaust, there is an American company who make a performance exhaust with all the correct attachments. I was also thinking that I could change the threaded section on the barrel by getting it turned to accept a standard Vespa exhaust or add the large nut to a standard exhaust and keep the threaded attachment on the barrel.Yanker wrote:No experience in this tune: But looking at the evidence I would follow Fasfrog's approach with an altered inlet manifold with appropriate rubber and carb of your choice (PHBL?): Reasoning = the Clutch capacity and lack of ready exhaust options.
The GS clutch has a strengthened band welded to the basket, so I think that might be ok. I was more worried about the actual gear change as the selector is not the strongest part.
I am hoping the tuning shops would have a look to see what can be done to the barrel and how easy it would be to change it to a reed valve set up, similar to the Quattrini.
If you need help to upgrade the barrel dont hesitate to PM me....
Size matters!