Modern Vespa

I had some scoring on the P200 piston. from what I read I should jump up to the 1st oversize and have the cylinder rebored. But, in pricing it all out, it's almost the same price just purchase an entire new cylinder assembly kit.

Here's what I mean;

1st oversize = 100.00
machine shop rebore, etc = 90.00 (I've been quoted everything from $75.00 to $125.00)

Full Replacement = 250.00 (This is order it, receive it, install it, as opposed to the above which is a 30 mile round trip with an estimated 7 to 10 days for the work to be done.)

Whatcha say?

yeah, this is true. I mean, for my SS180 i bored out and went oversized. Cost me about $150 total... ( 75 for the bore, 75 for the oversized piston and rings)

But i didn't have any other option.


Your biggest choice is whether to keep the stock top end, or put that money towards something with a bit more balls to it like a Malossi 210 or Polini, etc. I owned a Malossi 210 and it was the shit. Yes, you can just slap on a malossi and upjet, but really ...to unlock all the power you should dremel out the ports on your cases to open them up so that they match the ones on the malossi kit.

So, it begins to get a little more complicated if you go that route.

If you're asking new P200 top end versus 1st overed... i'd probably go first oversize only because it's an original, good quailty jug ... and you're not taking up space in the land fill, throwing away a perfectly usable cylinder. But, either choice is acceptable, i guess.

All things considered, I'd be inclined to buy the new one, if it is of good quality. and keep the old parts, in case you need them later.

What are 2 30 mile round trips worth to you?

Unfortunately, in this day, it is often cheaper to buy something new than it is to fix something old.

- Eric

A couple comments... I've never seen a stock P200 piston without some scoring, so I wouldn't necessarily replace it based on a visual inspection unless it's really severe. Compression test, ring end gap, or take it to someone with a micrometer to measure it out are better ways to tell if you really need a new top end.

Unless you just want a new one on there to know where you stand, which is perfectly understandable.

One more thing, on the replacement option, is your pricing based on replacing it with a new Piaggio top end, or an aftermarket/pattern top end? In my experience, the pattern stock kits are lower quality than the originals. It may not make much difference in how it runs, but it's worth thinking about if you're that kind of person.

So if I were going to stay stock and needed an oversize I'd have it bored out to the next size by a reputable machinist familiar with 2-stroke engines.

But frankly every time I've been in this situation I've just put a Pinasco kit on.

Agree... agree with that too... and could easily be talked into that... 8)

Hmmmm.

Would this require any jetting adjustments, etc? Says it increases from 10ps to 12ps?

http://www.sip-scootershop.com/EN/Products/41470800/Cylinder+kit+PIAGGIO+PX200.aspx

Figure the quality is square deal, and the price is even better than the other aftermarkets I have seen.

I dunno. It's still a cast iron jug.

If i'm spending that kind of cheese i'd rather buy one that's an aluminum cylinder with a nicasil sleeve. Lets you run higher compression and get more power out of it, better cooling, lower friction / resistance, harder to score or seize, etc.

You might not want to spend more than $200 beans, though.

True that. Shit... I didn't think about that. Thanks.

I appreciate the continued patience as I stumble through this...

I'll shut up. This sounds like a nice alternative, Birdsnest. Sounds like a cheap boost to power.

There's pros and cons to aluminum cylinders, and the same with cast iron.

I'm curious how Greasy will weigh in on your situation.

You can get a P200 cylinder kit for less than 250. ScootersO has one they are very pleased with for 180. Stock Piaggio is more expensive, yes, but Gene stands by the aftermarket. And he had every reason to pitch me the more expensive Piaggio kit, after all, so his recommendation of the aftermarket had weight. I WOULD be careful from where you source an aftermarket kit, as who knows how aftermarket quality varies... so I'm gonna support ScootersO on this and get one I know has a good rep.

The rebore and oversize is more scary to me, really, given that the results are up to the able hands of the machinist, and it costs the same.

+1

I would get that kit from SIP and be done with it. If your P is all stock and you want to retain reliability and squeeze a little performance out of it then that's the kit for you. Now if you were to build a street racer and have a back up scoot to ride just in case you blow it the fuck up...then go crazy with the motor.

I guess this debate underscores one of the nice things about P-series engines.

You have no shortage of choices when it comes to what you want to do with your engine.


My GS / SS? not so much. Overbore is really the only option. Still, my engine r00lz j00, fux0rz!

The price is right.
http://www.scootermercato.com/Scooter-Parts/Cylinder-Assembly/191989

Have you used this top end Matt?

Yeah for 20 bucks more you can get one you know is good from ScootersO

I've used 4 of them and they work great.

Well there you go!
We have a new winner

classic. lol

you must not have seen the shipping cost yet.

Yeah SIP is not a cheap source for the US because of shipping. Good parts though, so I have heard

Good to know! I'm picking one up in a couple of weeks.

1)Your piston can be scored pretty bad and cleaned up and run with no issues as long the ring grooves/rings are good and the barrel is not damaged (aluminum smeared on it is no big deal, just gouges into the barrel it's self). Wet sand any highspots, especially below the rings above any scuffs, that's where the smeared aluminum tends to collect.

2)If the piston is totally shot, you can probably still get away with some combination of new piston/re-ring/hone depending on the condition of everything.

3)Chances are it will run fine even if there are a few gouges in the barrel and you just stuck old worn rings in there anyways.

It's amazing what a simple non-performance oriented 2-stroke with 2 big fat rings can take and still run fine. I've cleaned up seized P200 topends over and over again and they would still pull hard and do 65+. Fixed a holed piston with an almost quarter sized hole up with a ground down bolt and washer once, rode around SF for a couple days freaking it would come undone at 7k rpm's and completely trash my crank and cases.

Thanks e. I think I'm gonna go that route. Rings look good.

If it turns out that I get some soft sieze at high RPM, then I'll replace the top end.

Appreciate everyone's 2 cents on the issue at hand.

Grazie,

Jeff

You can always contact Max at Motorsport...they order stuff from SIP all the time and they can place your order with other stuff they are ordering so you won't get hit with the shipping cost. Just an idea.