Modern Vespa

Making power in 1st and second gear, but loosing torque in 3rd and 4th. [pinasco 177, 20/17 dellorto, stock exhaust]

you've got the pieces (177) but you've got it corked up coming and going.

up that 20/17 to a 20/20 and if you can a better exhaust.

what's the gearing? if it's excessively short, with that combo you're out of breath and can't pull the longer 3rd and 4th

Can it be out of breath in 3rd and 4th and not 1 & 2?

Way to check gearing without taking the motor apart?

Yes, especially if it's a 10" motor in an 8" bike

Original sprint motor on sprint body running 10" wheels

Good, that's helpful. Do you know the history on the engine? Did it ever run well with the new parts.

No history on engine but I know the stamp on it is VLB and it is a VLB frame. She has always ran good it's just I don't feel the power in 3rd and 4th

So am I correct that if I add a bigger carb, and better flowing exhaust I would feel more power in 3rd and 4th but in doing so 1st and 2nd will be more power too?

...More power is more power?

I'm really looking at keeping my carb and exhaust so that means the gearing could improve the torque?

yes, greasy already gave you the low down- you can do them independently if you want to try just the carb first. you will need to jet appropriately, the jetting will be different on the 20.20

If youre buying a 20.20 carb, personally, id get a 24mm SI. However, if youve got a 20.20 to hand, then use that. Then if you want to max out that bolt on kit for speed without porting etc, a road 2.0 exhaust, or if you want torque, want to drive 2 up and lose about 5-6mph on top end, a polini box. You will be good for 60mph all day long, maxing out about 64 unless you change gearing and modifying the ports. Just my pennies worth, plenty of other options of course and the suggestions will flow in, but for cheapness/reliability if that fell on my lap thats what id do, but i am on a budget these days as my daughters are too expensive.

https://www.sip-scootershop.com/en/product/racing-exhaust-pinasco-touring-classic-251cc-260cc_78249100?q=Exhaust

Is this better than a sito or 2.0? In terms of low end mid and high end torque/speed? And I want to go with si 26 or 28 or even 30. With right jetting will it work on Pinasco 177? What are the performance increases between these carbs?

No, that's not the exhaust you want. It's for a P200, plus it's a bad choice, period.

Get a Polini box and be done.

Polini compared to the SIP road XL, 3.0 and 2.0? And Pinasco 177 plug and play exhaust manifold flange compatibility? Should I go 24e or 26e?

The Pinasco 177 is compatible with the Polini box. It's the best (pretty much only) game in town for two-port motors other than converting to three ports.

We've beaten the box exhaust topic to death on here more than once, and the current winner for pretty much all non-exotic use cases is the Polini box.

Ok thanks for the info. I'll purchase soon but now with this setup 24 or 26 carb. SI 26 is cheaper, why? Looking at SIP for carbs for my setup.

With the two-port, you're going to be best off with a 20/20 rather than a 24 or 26.

Think of the motor as a pump. It doesn't move enough air for the venturi effect to work adequately at low-to-mid throttle ranges with the 24/24, so you'll always struggle to get it dialed in well in that range--which is where you spend most of your time riding, so it matters.

You would need to do a LOT of dremel work on the cases, both porting the transfers as well as widening and increasing intake timing, plus go to a 60mm crank and raise/square the exhaust port to even begin to need a 24/24 with the two port Pinasco.

With all that in mind I feel like not tuning my current setup and shoot longer to start a Malossi VR-One build. If I was to build a VR-One engine with the Malossi 210cc cylinder kit, will I get good lows, mids, and highs? What does that engine perform like?

You're moving into an entirely separate conversation now, going from a small block (125/150cc) 2-port to a large block (200cc) performance case build.

You can get loads of power off a well-built small block motor. I have a small block motor in my GL that does almost 80 MPH if I want to, and could do more with longer gearing, but...why?

Tell us some more about what you're hoping to achieve and your riding style and we can give you better advice. Also, realize that you're at the beginning of a long, expensive, and learning-intensive road if you decide to go the serious tuning route.

I could go with one of these. These are 3 port? Back to that Malossi VR-One, I don't want crazy power as it will just get too much. I've seen people ride Honda CR250's and it just wheelied in 1st. Without spending to much just a bit more power would be good as it puts me with a small project and making my bike a little more fun To keep a smallblock what cylinder would be an upgrade to my pinasco 177? If that case is a 3 port, I will already make some gains.

You should be able to get all the power you need out of your existing motor, you just need to set it up correctly, i.e. with the 20/20 carb and a modern box exhaust.

Someone on here can hook you up with a 20/20, I expect. Heck, I have a few of them I could send it your way. Grab a Polini box or SR3. The Polini will give more grunt. The SR3 more top end RPM's, so wider power band, but won't come on to it as quickly. The Polini is probably a better match with your port timings, though. Those two items will set you back $300-400 US with shipping.

Dialed in, it'll hit close to sixty, assuming you're not a giant viking-sized rider.

Those GL cases are also 2-port, so they wouldn't get you anything over what you have now.

You need to consider that you're going to want to upgrade ALL your suspension (shocks, engine and mounting buffers), plus potentially go tubeless tires if you're going to be doing much high-speed riding, though. That's a few hundred bucks right there.

appreciate the info. Now when I bought my Sprint it came with the original carb which is 20/17 and a SPACO. I'm running the original Dellorto, the SPACO may be 20/20. I'll check my parts bin tonight.

stop trying to spend dumb money and go VR1 or get another motor. what you've got will work.

put a 20/20 on it and see how it goes. then put a stock P pipe or polini box on and see how that does. get your jetting and timing dialed in. from there, maybe you swap out a clutch gear to get more ideal gearing for your riding style.

2K+ on a whizz bang motor isn't the answer to every problem.

You shut your filthy mouth!!!

you're over here cutting into my business model! how else am I supposed to sell all this used small block stuff and my other p2 junk?!!

all kidding aside, my reaction is a hold over from my car/hot rod stuff. everybody is all: I need a bigger carb or bigger cam!! when in reality it's just a totally mismatched set up or it just needs dialed in.

.


Cannot agree more. Add 20.20 carb and box exhaust. Then you might just want to increase primary to a 65.

There's my carb. So SI20, I guess that's 20/20?

20/17. Float is chinese and i wonder if the rest is a chinese copy.

Ok now I know. I am close to ordering this then, https://www.sip-scootershop.com/en/product/carburettor-dell-orto-si-2020d-without-oil-pump_23917700?q=Carburettor%2C%20Manifold but anyone think it's better to buy a used one for maybe $75 and someone could throw in some spare jets in increments?

question: is this bike of SEA origin? I'm not trying to make a dig at you or anything, just trying to get an all over idea of what you're working with?

I see a janky carb and that leads me to believe that other parts might be suspect. which that can be a problem when you're trying to build or tune something.

you can have all the good bits and bobs but if the foundation is junk then you're never going to get there.

anyway, I'm fairly certain that I have a 20/20 kicking around somewhere. I can check inventory and see what all I've got if you're interested.

Yes I am interested. I've been riding hard all summer so I have some confidence in my engine already, I'm not dismissing what you are saying either though.

When I pulled my speedometer out weeks ago there was Asian writing on the underside of it. My paint feels too shiny for the ugly worked metal underneath. I don't doubt it's SEA origin.

Do you have a new gasket to go with it? And anyway if this motor breaks I can fix it. It's all a learning process

Sounds like it's about time for some PHOTOS.

Photos of my engine? Or just in general anything?

tasteful nudes preferred.

Of me lol! anyway did you find a 20/20 in your parts bin?

Hoa https://en.wikipedia.org/wiki/Hoa_people

Some asian word on speedo

Paint chipped on front mudguard showing ugly metal.

Original Dell'Orto that came in a bag with the purchase. Another 20/17D.

If I recall from his other posts with the Pinasco kit he put on, yes it is. It even has the yellow booties…

Judging by the crap carb, engine needs an overhaul for sure to see what's going on inside…