Modern Vespa

I am new to this forum, and new to scootering. I have recently purchased a '62 VNB. I am having the time of my life on this thing!

I read on another forum someone talking about how 3 speed, older 2-stroke Vespas should be shifted differently from what I am used to - and specifically, different than newer 4-stroke trans.

I have been using my ears to hear when it makes sense to shift, but this post mentioned that it is better to "wind out" each gear before shifting.

Can someone clarify this for me? It seems counter-intuitive.

Thanks in advance.

yea these vespas need a good throttle to get the gearing right so as not to wear the engine too much. max possible before explosion is what...9k rpm? so i usally try for about 7k rpm. and yea i just use my ear to guess...

Sorry, I guess I needed a little more explanation than how-to. Although i appreciate that too.

I am wondering why this engine would be that way??? It seems so natural to shift as you get toward the top of the RPM range, instead of pushing it up past what feels comfortable.

Can anyone tell me why it would be this way?

Also, without a tach I need to get used to hearing it "wrong" (higher than other bikes ive ridden) before shifting? Am I getting this right?

2-stroke engines don't have valves like 4-stroke motors do, so in theory they don't have a "red-line" in the same way as 4 -stroke motors. The limiting factor with your engine as to how high it will rev is how much power it puts out. Most stock vespas top out at around 6000rpm. Only motors tuned with "sport" components can rev to 9-10,000rpm

Nortstudio, google some dyno graphs and look at the power curves - as rpm rises so does power, upto a certain point, then power drops off.

What you are aiming for is to shift when you are at the highest point in the power curve, so that when you are in the next gear, the revs haven't dropped off too much and you are high enough up the power curve to carry on accelerating.

On 3 speed motors the gearing is wider apart than it is on a 4 speed, so the further down the power curve you will be on each gear change.

If I was only 3 beers into tonight this would make more sense.

Thanks so much. That's exactly what I was looking for. In theory, I completely understood the technical aspects of the RPM/power, but needed a little backup for operating a bike in a way that sounds somewhat "wrong" to me in it's whining at the top of the RPM before shift.

But I guess I was feeling it right - and I have been shifting along the guidelines of power, so I should be ok.

Hope the night ends (safely) with a few more beers

Well put Steelcap. I must have forgotten the part about tuned engines. Thanks. I learn alot here.

I thank both of you for the help.

Here is everything you need to know:
The Gentle Art of Shifting

Thanks for the link. Very informative, but this I have down already. I am really more concerned with (and less so since the help here) about the idea of needing to bring the RPMs to a level higher than what sounds 'normal' to me.

I guess my post should have been more about RPM and gear ratios. The idea of winding the engine way up before shifting is foreign to me.

I am going to be more conscious of the peak of power, and the following leveling or dropping, and how that sounds. After the resonses here, I feel as if I have been instinctually shifting at the correct time - but the post on another forum sorta threw me for a loop.

Thanks everyone!

I can't say that I pay that much attention to how the bike sounds....more of how it feels, like everyone said above, when the power slightly drops slightly I shift.

How about a picture of your 62?

Here is a photo...[/img]

Correct:

bwahhhhhhaaaaaaaaaaaaaaaaaaaaaaaaaaaa: shift bwaaaaaaaaaaaaaaaaaaaaaaa: shift bwaaaaaaaaaaaaaa etc

Incorrect:

Bwahhhhhaa shift: bwwwwwahhhhhhhhh shift: etc

That just about clears it up! Printed "sounds" are worth a thousand words...

Thanks.

You'll be able to tell. If you shift too early you get the bogging (bwwahhhhhh) sound.

That is fine for scooting around the city by yourself and not trying to go fast or speed but just riding around comfortably.

If you're trying to keep the speed up and running with someone on the back that bogging from shifting too early will be felt. Find the comfort level from when you rev out in one gear and then when you hit the next gear the bogging is eliminated...going from bwaaaaaaaa to bwaaaaaaa without the bwhhhhhhhaaaaahhhh.

I started a blog (like everyone else!) about my experiences getting a first scooter and getting into the scooter scene. Thought that some on this site might enjoy.

http://newtoscooters.wordpress.com/

Good looking VNB. Bought the exact same machine (1962) in 1964 and loved the hell out of her. Served me well for 41 years. Hope you get similar service! None of the various Vespas nor either Lambretta I owned during that time was as near and dear. Even though they all served me well.

Al

Ah, memory lane. That looks like my first Vespa from '64 as well. Same color except my seats were black vs. brown, and I didn't have the rear rack. Not the fastest 125cc machine at 6000' plus altitude, but certainly fun. Good tips on revving high enough prior to shifting so the next higher gear will have the engine in the power band when done.

Thats a post of mine from another forum from 2 1/2 years ago that he's talking about. I just checked my PMs there and saw a message from the OP here.

I didn't really talk about shifting specifically on a 3 speed, just about shifting on a Vespa generally and needing a 4 speed VNB version to cope with a VBB top end put on it. Here's the post: http://nyscooterclub.com/forum/viewtopic.php?f=1&t=7990

What about breaking in a motor? You shouldn't really rev it out, or should you?

Depends on who you talk to - some people do the slow and easy for a few hundred miles route, and some people go balls out and others advocate doing the heat cycle method

Thanks andrea, I knew the post was old, so I figured maybe you were off that site, and the PM would have floated into the ether.

It turns out I have been shifting correctly all along, but wanted to confirm that I wasn't screwing up by not letting it wind up enough in each gear first.

If there are any other suggestions you would make, about the scooters performance, or my own, for my VNB (3 speed) with the upgrade to 150cc, they would be much appreciated.