Vespa Grande upgrading

Ok, I've got my first moped - a 1978 Vespa Grande Deluxe. It goes about 25-27 with the stock 12.12 carb, air filter, and pipe (it looks like there's actually a dented hole in the exhaust in addition to the normal opening). I'd like it to be just a tad faster in traffic. Can I simply swap in a 13.13 carb (upjetting of course, probably gonna try something in the 60s), a high flow filter, and a performance pipe? Or do I have to do something to the engine? I know people up the cc's with kits, but being totally new to the craft, I'm not sure if I need to do anything to the engine (e.g. bore out the intake to 13mm, etc.). I'm just looking for a little speed improvement. Essentially, if I run a few upgraded performance parts at 50cc, will they even do anything? I know there are other threads about this, but if someone is willing to give something of a beginner's breakdown, I'd be most appreciative.

Thanks!

Re: Vespa Grande upgrading

Bill - Congrats. Grandes are nice bikes, and it's great that it is running out of the box. There is a lot of info on here about upgrading Vespas from stock. The long and short of it is that Vespas are restricted out of the box with a small carb and its pipe and the stock variator (which are all actually pretty quiet and decent and reliable for a stock set up). The first thing would be to get a better exhaust. Circuit pipes are a good place to start. From there, I would upgrade the variator, then a cylinder kit, then the intake & carb. Getting a new carb without doing a bunch of other stuff won't do much. Search around though. (edited)

Re: Vespa Grande upgrading

Yeah, unless you feel like doing engine case/crank modifications, you're never going to get the most out of that carburetor setup. Definite first upgrades would be pipe and variator, which would give you a lot of all around tuning and performance. The stock variators can be notched so that you get full close on the front pulley cheeks, so that's a free 5 mph assuming you're handy with a dremel.

Re: Vespa Grande upgrading

Alright, I'll start with a pipe and hi-flow filter (probably need to upjet a little bit, maybe in the low to mid 50s? Stock is 49). Will a specific pipe work better than others for increased speed if I'm not yet modifying anything else? I've got the stock-like Tecno pipe in my basket at Treats right now (https://www.treatland.tv/vespa-tecno-stock-pipe-p/vespa-stock-pipe-ve20002.htm).

Is that a good starting point or would a more expensive performance pipe give me an extra boost the stock-like one wouldn't?

Thanks for the help!

Re: Vespa Grande upgrading

bill,

ive said many times before and will again ....mod your stock variator for instant $0 budget performance gains.... (a few us up posted stock vario mod pictures in those threads also) shave the brass spacer out from between the variator faces for better lowend and better top speed, its a no-fuss no-stress no-brainer mod and worth the effort.... notching the cup walls is a little bit more complex but worth a few extra mph also if you feel good about a steady hand

plenty of folks have posted on sha jetting for vespa if your search all and check the spreadsheet, but there are a couple recent threads that might be helpful also... my stock cylinder and circuit pipe on a 12.12 carb is usually a 58 jet maybe 60-62 depending on test runs and esp if you go hiflow filter...

Re: Vespa Grande upgrading

pipe will have the greatest effect. unless you reeealy want to keep the stock look, you want an expansion chamber exhaust, it acts like a turbo on a two stroke motor.

Re: Vespa Grande upgrading

Jonathan Ackerman /

Hey man,

It's your neighbor Jonathan. I just got done notching some hobbit variators so I would be down to help with doing the grande one. Also I'm super interested in seeing how that thing works!

Re: Vespa Grande upgrading

Jonathan Ackerman /

plus I have a million dellorto jets and a 16.16 sitting around that if we find all the pieces for we could slap on and see what it does

Re: Vespa Grande upgrading

Monti S knows what he's talking about when it comes to Vespas. Search his posts.

Also check the tuning spreadsheet. FWIW I got 5mph on the top end plus better low end with the tecno "speedy stock" pipe and 13.13 SHA with malossi red filter. Which bumps my Bravo up to a whopping 31mph... Variator mods to come. Currently running a 57 jet at 800 ft and can run WOT all day.

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