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Post by smallframenyc on Sept 23, 2019 19:36:41 GMT
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Post by jbcollier on Sept 24, 2019 0:46:07 GMT
Nothing wrong with the 3 spd gear box. Why not fit the cylinder and see from there. You can swap in a four speed box later, no problem. The Polini 130 kit is nice and torquey and will work just fine with the 3 spd.
When I build 130 Polini engines for people, I keep the V90 primary gears. It makes for a scoot that goes like a rocket, easily out accellerating P200s. With the Polini banana pipe and 19/19 carb it will easily pull 55 mph/90 kph and, even better, hold it up hills.
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Post by smallframenyc on Sept 24, 2019 14:08:53 GMT
Nothing wrong with the 3 spd gear box. Why not fit the cylinder and see from there. You can swap in a four speed box later, no problem. The Polini 130 kit is nice and torquey and will work just fine with the 3 spd. When I build 130 Polini engines for people, I keep the V90 primary gears. It makes for a scoot that goes like a rocket, easily out accellerating P200s. With the Polini banana pipe and 19/19 carb it will easily pull 55 mph/90 kph and, even better, hold it up hills. Thanks jbcollier, That is good to know. I was considering this sip performance kit: www.sip-scootershop.com/en/products/tuning+kit+polini+road+130+cc+_10401000It has a primary gear ratio 2.56 (have no idea what that means) Didn't really want the faco pipe that comes in this kit thou.. So I can keep all the gearing, I'm thinking, polini crank, bearings, seals, reinforced clutch plates/springs, polini 130 kit, polini snail (or sip road), 19/19 carb
the crank: www.scooter-center.com/en/crankshaft-polini-rotary-valve-51mm-stroke-97mm-con-rod-vespa-pv125-et3-125-pk80-s-pk125-s-oe-19mm-cone-p2100056Do you think this setup will suffice? Cheers |
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Post by snails on Sept 25, 2019 11:20:14 GMT
As jbcollier says there is nothing wrong with having just 3 gears. I have a 3 geared 125cc lambretta and its fine - since the gearing is designed for the power produced by the engine. The time you need to look at your gearing is if you increase the power output significantly higher than the original engine designs power, because you engine will be screaming its tits off at full throttle and you wont be getting the speed increase your increased power deserves. Even then you dont necessarily need to change the number of gears, just the gearing ratio. Your engine now has more power so it can pull taller gearing have a look at this site (it was originally developed for lambretta engines but I think there is a vespa version too now, I cant check as the site is blocked on my word pc) It demonstrates the effects of changing gearing ratios on your engines top speed in each gear and you can play around with different gear box options. avantone.wordpress.com/2012/06/11/gearboxvisualiser/Hopefully someone can explain better about gear ratios for you. I understand them when I read up on it but cant explain off the top of my head |
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Post by jbcollier on Sept 25, 2019 13:48:54 GMT
Nice crank! Reasonable price and way better quality than the usual Mazzucchelli fare.
"So I can keep all the gearing, I'm thinking, polini crank, bearings, seals, reinforced clutch plates/springs, polini 130 kit, polini snail (or sip road), 19/19 carb"
This will make for an excellent round town scoot.
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Post by smallframenyc on Sept 26, 2019 11:54:50 GMT
As jbcollier says there is nothing wrong with having just 3 gears. I have a 3 geared 125cc lambretta and its fine - since the gearing is designed for the power produced by the engine. The time you need to look at your gearing is if you increase the power output significantly higher than the original engine designs power, because you engine will be screaming its tits off at full throttle and you wont be getting the speed increase your increased power deserves. Even then you dont necessarily need to change the number of gears, just the gearing ratio. Your engine now has more power so it can pull taller gearing have a look at this site (it was originally developed for lambretta engines but I think there is a vespa version too now, I cant check as the site is blocked on my word pc) It demonstrates the effects of changing gearing ratios on your engines top speed in each gear and you can play around with different gear box options. avantone.wordpress.com/2012/06/11/gearboxvisualiser/Hopefully someone can explain better about gear ratios for you. I understand them when I read up on it but cant explain off the top of my head Thanks Snails, I downloaded the gearbox visualizer, that is a great tool! Thanks for passing that along. I will do my research |
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Post by smallframenyc on Sept 26, 2019 12:14:15 GMT
Nice crank! Reasonable price and way better quality than the usual Mazzucchelli fare. "So I can keep all the gearing, I'm thinking, polini crank, bearings, seals, reinforced clutch plates/springs, polini 130 kit, polini snail (or sip road), 19/19 carb" This will make for an excellent round town scoot. Thanks jbcollier, Thought that crank looked good. Need to count my gear cogs and see what I have, but from what you've siad I think i will go stock gear box, and see how she goes. Cheers |
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Post by dazzz on Sept 26, 2019 16:27:52 GMT
If it was me I’d swap the primary gears to 27/69 and use the 4 speed gearbox out of the 50 engine , you would have to split the engine again to change the primary’s and gearbox if it don’t meet what you are looking to achieve, unless you want a red light bandit.
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Post by tzsteve on Oct 3, 2019 15:10:16 GMT
I have a reasonably quick 125 ( quatrinni ) my gearing is a 4 speed box with primaries mid way between vespa 90 and 125
going a little lower than the standard 125 set makes for a good setup round the city but the standard 125 type will be fine
it just means you wont be able to use 4th while going up a long / steep hill
hoe heavy you are also makes a difference
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