Modern Vespa

I fitted a Malossi 210 yesterday and swapped my Sip2 road for a polini box. I can't believe what a difference it makes however I do have one issue.

It sounds like it is blowing a bit but maybe just the sound the polini box makes (normally used to the sound of the Sip2 road). I removed the head and no visable leak so used a bit of liquid gasket and torqued it up to be on the safe side.
There is a slight bit of oil on the top of the exhaust box and a little on the rear of the exhaust manifold. I torqued that up and used locktight on the Allen bolts supplied. I'll probably take it off and use some RTV around the manifold edge next weekend.

Anyone else had this issue with newer Malossi kits?

Hi,

I don't think it is the Malossi kit that is the issue, but the Polini pipe...

I'm running Polini box pipe on 3 of my scooters, and they all "leak" at the connection to the cylinder stub.

Apperantly the cut in the pipe (to be able to tightening it on the exhaust stub) is to deep/long, so the exhaust fumes escapes there.

And as it is two stroke, the oil in the fumes will show.

Ah ok thanks. Personally I don't like the clamp as it feels cheap (bolt dose not hold so you needs a spanner both sides), guess I'll look to see if there is a better clamp.

You should have an airtight seal from the cylinder to the exhaust. It's it's spooging out those slots (SIP Road's also do it), you can make shims for the slots from an old beer can. That plus sealing it with red or copper RTV with get it nice n' tight like it should be.

Shims, RTV, and definitely get some spring hooks welded on that Polini box. Why they don't come with them I don't know.

How's the timing, carb and jetting so far?

I added extra cut opposite the existing one and used jubilee super clamp. And copper silicone sealant ofc.

Timing seems fine on IT(18). I went one up on the standard pilot 55/160 and looks good. Mid range is responsive with a BE3 and one up on the main stack. Put the 130 main jet in but not tried WOT yet as still taking it a bit easy.

I have noticed a bit more vibration though when going over 50mph. That could be the forks need tightening, the fact the Polini touches the stand spring clip or the Maz crank is warped so need to work that one out.

Thanks for that, I think I'll give that a go and see if it helps. Failing that I'll accept a slight performance loss and put my Sip2 on.

The jetting you have now with the 130MJ is very common. It works but a bit rich low and a bit lean higher up.

So more like a 132-135 ?

Better to change the air corrector. AC140 might be rich enough.

Thanks for saving my piston 🙂 I had forgot about the AC and it's a 160 at the moment (so a 140 on its way).

You may find that that SIP Road 2 outperforms the Polini, but you'll need to be taking it up the rev range. I love the Polini on mine, but I'm generally in the 6500 - 6750 RPM range.

I was looking at https://scooterlab.uk/vespa-big-box-exhaust-shootout/ and it reckons the polini box is 1.8hp more than the Sip2 on the Malossi (hence me changing) …