Modern Vespa

The p125x feels very unstable at speed.

I have new zippy 1's and new tubes, pressures are approx 19 front
36 rear...

If you take your hands off the grips, it pulls hard to the left...


Speeds over 60 are twitchy and scary.

Did this start after you got the new tires installed? Perhaps they're not balanced.

My friend has been riding his PX for 10 years plus. Recently whils following him on a ride I noticed his rear wheel looked wrong. When we fulled over it turned out he had put the wheel on backwards! It would be nice and easy if that was your problem.
Are Zippys directional? Worth a look I guess.

Yes,
They are directional... The tire goes one way for the rear, and the other way for the front...

I have them on my sprint, and it doesn't feel like this.

I wish I could explain it better...
It feels really squirrelly.

Make sure that your steerer and handlebars are lined up perfectly. There is a hole below the headset that you can loosen and make them straight. Make sure you tighten the bolt enough when you are done or the from wheel will maneuver left or right free of the handlebars.

What I want to know is how your getting up to 60 ?

I have a p125x and it barely goes over 45 with a tailwind.

That squirrelly handling can also be from steering that is too tight or bearings that need lubrication. I recently dealt with this on an Li125.

Option A: "60 Indicated"
Option B: "60 KmPH"
Option C: Off a cliff

Polini 177 matched ports, and sip road...

62mph on gps

I think I need a new top end.

This is with the stock crank, and the 20/20 carb.

Hey Chris, the squirelliness could be a bent or incorrectly mounted wheel or hub. Get the wheels off the ground, spin them, and look for wobble or run out. Also check the tightness of the steering bearings. Pulling to the left sounds like a bad rear shock. Also, 36psi is way too much air.

62 mph.. woohoo. Polini delivers!

I was pretty pleased...

I'm sure it has more to offer, but I was still in the break in period, and it got sketchy with the questionable handling, so I backed off on the throttle.

The handling got scary, which to me isn't right. I would expect better handling characteristics from a p series over my sprint...

check for properly installed tires etc.
Are your motor mounts original and in good condition? badly worn mounts can cause it to pull

This was a barn find scooter with 630 miles on it...

Can the shock and or motor mounts go bad just from sitting?

Rubber degrades and hardens over time. We wouldn't ride on 35 year old tires. We wouldn't trust 35 year old tubes, so we should question all rubber parts on that scoot, including motor mounts, and shock mounts. Not to mention shocks front and back.

as already mentioned, your steering bearings are notched.

of course. As mentioned rubber dries out. Stock shocks suck even new !

I'd agree that 36psi is way too high of pressure for the tire. Try lowering it first and go from there. I ride about 25psi in mine.

The factory tire pressure is 17 front and 35 rear. It's on the sticker on the leg shield, and that's what I run.

35 rear when you have a passenger. Solo - 18 front, 26 rear.