Modern Vespa

Hello hello!

I've been riding my DR 177-equipped P80X all over Solano County this past couple of years. It's been freaking fantastic! However, I ride in a land packed with people driving too fast and impatiently on country roads. It happily cruises around 45, but I feel I need more speed if I am to escape this highway-locked little hamlet alive.

Here's the deal: I've got a set of P200 engine cases, with a stock crank, gears, and cylinder. The clutch is toast, and the cylinder head has had half its fins broken off. Bearings are roached. All those bits are just sitting there, wishing they were an engine.

If you had ~$800 to burn on this, what would you put in?

PS---While I can hit ~60mph with the DR kit, that's on a flat grade with the wind at my back and the engine just screaming. I just want to be able to hop on and off state highways where traffic is moving around 55-60 mph without pegging the engine.

Been there done that a few times (literally), not only on the fast traffic but also I have done a P200 engine into a Sprint Veloce and to the PX150. There are some good and some bad and here is why. The good of the P200E engine with its tall gearing is obviously the relaxed RPMs but a 150cc kitted with a Malossi would smoke the stock P200E engine any day.
You can try to do a Clutch cog on your current set-up, try a 22 teeth and you should be able to cruise at 60 mph and higher without any issues. The indirect problem of putting the P200E engine with its tall gear is the 4th. The rpm drop between third and 4th is abismal. It feels good on the first 3 gears until you shift to 4th and you fall under the power band at certain speeds/rpms and it just doesn't have the power nor the torque keep pushing it.

You have to really think about the type of riding that you will be doing. How often do you go out there on fast traffic and how fast you go and how fast you want to be. My own P200E with the Malossi 210 or the spare P200E also with the malossi 210 and P200E gearing on the PX150 and the sprint Veloce acted the same way, both would fall flat on their faces in 4th gear and the solution would be going above 65 mph(closer to 70MPH GPS) to start feeling the power again. So many people on this forum that don't even have a GPS that you can not take their word for it because the speedometer of the Vespas are so far off and that 10-11 mph margin of speed error means a world of difference.

In summary. I can go from 0 to top speed on my kitted 150cc scooters(Sprint Veloce of PX150) before you click your eyes but I absolutely ca not say the same thing on my P200E with the Malossi, that 4th gear kills it!!! while the 150 kitted will hit red line fast on all gears. My vote goes for a 22 teeth clutch cog for now, it will cost you like $85 , you change it in 1 hour and go and see if you like it.

Just spend the money on the 80 engine. New cylinder, crank and exhaust and it will be quicker than any 200.

I like what I'm hearing, fellas.

I have already put some money into the P80X engine, on account of it being essentially hobbled from the factory. When I was a lost and wayward soul in the darkness of 2022, I set about hammering back those deficits WITH MONEY. Apart from the DR177 kit, it's got a Mazzucchelli crank to increase stroke from factory 48mm to 57mm, and because they have a bonkers gearing ratio from the factory, a 23/64 primary gear Malossi kit. Carb is also swapped to a 24.24E and it's rocking a SIP exhaust (replacing the cracked/coked OG unit). It's like a fever took me in those days.

It still sort of pulls like a tractor in first and second gear — it's…unique. I wish you guys could feel how it is to ride. Typing this all out though…it's my gearbox holding me back, isn't it?

No. Your gearing now is almost the same an EFL PX150. If you had a kit that would do 8000rpm it would be plenty fast enough.

What does a kit capable of 8000 rpm look like?

I'm getting a little over 90 psi after a dozen kicks with a compression tester. Seems low, yeah? I had a hard seize a couple of years ago and only did a bit of cleaning up of the cylinder after addressing the underlying cause. Might want to take a look there before I do anything.

perform a "wet test" and see if your compression bumps back up. If so, then you might need a hone and new rings or even possibly a rebore along with a new piston. And if you need to bore and get a new piston on a DR kit, then you might as well buy a new kit from a different manufacture.

Would expect 9000 from this kit!
https://www.sip-scootershop.com/en/product/racing-cylinder-malossi-mhr-177-cc-3118102_31181020
There are so many 177 kits now but this one is the fastest bolt on.

For a "daily rider" build I would personally stick with twin ring pistons. Twin ring kits last longer and are overall better for street riding. Longer ring life, added piston stability, and lower chances of melting the piston to the cyl if you mess up on jetting. More rings = more piston cooling as theres more contact points to the cyl for heat transfer.


I have a VMC Super G 177cc kit and it is one of the better and more modern entry tier kits. The DR177 has very lazy porting VS almost all of the other 177 kits on the market. Check out the VMC Stelvio as well!

You might want to try a T5 4th gear as well. It is 1 tooth shorter and puts the powerband in a better spot especially with a higher revving kit+pipe and a tall primary reduction like the 23/64 we both have.

Oh wow these are all great looking! I'll need to find a set of 125 engined cases though to use them. The P80X engine cases have a narrower opening to accept a cylinder. I had to choose between what SIP had on offer: the DR kit, a Polini jug https://www.sip-scootershop.com/en/product/racing-cylinder-polini-177-cc-by-sip_10060000?usrc=cylinder, or this pricey Quattrini kit https://www.sip-scootershop.com/en/product/racing-cylinder-quattrini-m1x-millemiglia-11-172-cc-by-sip_10080000?usrc=cylinder

125 engine cases, or pay to have something turned to fit in P80X cases.

I often hear this about single ring pistons. And you're mostly correct for the wrong reasons. Twin rings work better at lower revs, single better at higher. At higher rpms the crown is mostly cooled directly to the head.
Single ring can often last longer than twin, as the single ring has oil on both sides of it, whereas twin only have oil on one side, with the space between only having a tiny amount of oil that has leaked past the top ring.

Difficult with the px80 cases. Could slightly tune the DR kit and fit a GS piston. That works. Would get you up to 7000 rpm for sure.

i've machined Rally180 cases to fit any large block cylinder, so these P80x cases should be no problem to machine to fit any small block cylinder. two other options are to find a set of p125 cases or spend the money on a set of Malossi PX150 cases.

Or I have these perfectly good P200X cases here.

P200e or PX200 ? either way, those would work.

P200e, yah, thanks.

I have almost a whole P125X go fast engine, sans cases and a new cylinder. The world is not raining used engine cases, though?

I could build this P200e engine and continue to ride the P80X in the meantime. What does a slightly goosed P200e engine look like? I know need a muffler and the usual bearings/seals/clutch at the very least.

Or I just keep going with the P80X kit 'til it really gives up the ghost. I yearn to escape this suburban bubble, though.

I'm not familiar with the PX80, but if it can be reworked to use one of the fast small block kits available, you could certainly make it fast enough for 2 lane state highways. It would likely have quicker acceleration than a bone stock 200. Since you already have some experience with tuning, working with what you have could be a good option. Because I haven't been very successful in building a tuned small block, a stock with a little more 200 would tend to get my vote.

I like the 200 engine a lot for the kind of 2 lane state highway riding you are describing. Even bone stock, it will easily handle it without a fuss. The gap between 3rd and 4th is absolutely a thing. The stock 4th kind of feels like an overdrive gear. You really have to wind out 3rd to keep the party going in 4th. There is always the option of a short 4th, which apparently helps a lot and is something I may end up trying. The zippy fun quickness of the 177/187 is something I miss with the 200. If the 187 I am working on ends up working out, my opinion might change.

A wet test just now on the DR cylinder boosted compression up to 115 psi, which is not a shock. Time to ponder.

I quite like how this setup performs. It's just that final top end speed that's not ideal for the environment I ride in.

Y'all I went for it: found a set of P125X cases, nabbed a VMC Stelvio kit and did the requisite prep work. It's a real Frankenstein situation in my garage (P80X+P125X=P205X!!!). I was just about to close up the engine, but I've hit another hurdle and could use wise words.

The cush drive spindle from the P80X has a 13mm small end (like a PX150E, I think?) that straight-up won't fit into the VNX case. However, the spindle from an early model P200E I have on hand fits nicely. Before I disassemble the cush drive and create a new unholy fusion, do you know of any mechanical reasons that it won't work?

Also, side note: I have a new original-style clutch basket. Do I need to/Should I get one of those reinforced baskets to keep this higher-revving engine from flinging the clutch apart?

Well, it turns out that the P200E spindle is around 14.7mm where it slides into the cushion drive assembly. Too big for my stuff, even though the small end fits nicely into the cases.

Does anyone know which spindles measure around 12.7mm in the shaft, but with an 11.5mm small end where it slides into the case?

So it turns out that the P80X gearbox is such a weird little creature that this whole case swap project may double in cost, unless I can figure something out.

I can't use the original P80 cush drive spindle/input shaft in this P125X case because the small end is 13mm like a PX (case accepts 11.5mm).

A P200X spindle is both too large to fit the case on the wheel side and too thick to fit in the P80 Christmas tree.

A just-purchased P125X spindle fits the cases nicely, naturally, but at 14.7mm where the shaft fits into the gear tree is too large to fit.

I see my options as:
1) Forever sulk miserably and never ride this scooter again in this life or the next. (Zero Dollars)
2) Cram P200E gears into P125X case with Super 150 spindle/input shaft -- but how would this perform with Stelvio 177 kit? Maybe do the T5 4th gear? (Several dollars)
3) Source entire P125X gearbox and pair with existing 23/64 Malossi primary gear kit (All the dollars)
4) Find someone who can mill P80X spindle small end down from 13mm to 11.5mm (Literally no idea on cost/quality/outcome of this)
5) Custom CNC a spindle/input shaft from scratch (Chunk of change)

Any other ideas?

Option 5 it is. Turns out that one-off CNC milling services are pretty cheap now.

After taking many measurements and an hour of CAD, I have a design for a cush drive spindle that marries the P80X cush drive christmas tree to the P125X case. Turnaround time, including shipping, should be around two weeks. Fingers crossed!

Great solution! I really need to learn CAD. Very impressed.

how do you spec the material and hardness so it doesn't explode?

Send me your spindle and I'll turn it down in the lathe.

LEGEND!!

Total guesswork, given it's not a shaft that rotates. It'll get milled out of AISI 4140 alloy steel. I'm not an engineer: just a schmuck with a free Fusion 360 license.

That being said... What! Brother, I would like to take you up on this offer. Thank you! I'll DM you.

It's just the small end so no biggie. Flat rate box from the post office is cheap enough to make worthwhile. Then you can put it in and see if it works without spending a bunch of money.😉

Here you go.

Aww yeah you're the best! 10/10 guy!

don't lose the kick start gear, as it took me almost a year to find one for my p80 motor, as it is another item that is unique to the motor.

Yep! Mine's got a couple of teeth with wear and I am pondering whether to replace or not. They're hard to find!

for us in the usa yes, as only drt remade them years ago. i had to have a guy in Germany send me one, as it is a odd size,

Okey doke. Thanks to the amazing BajaRob, we are back together.



With the engine closed up, reinstalled and timing set, it started on the second kick. Also now I what actual compression feels like!

Here's what I've got cooking:
-VMC Stelvio + case ported
-Mazzuchelli sport crank
-SI 24/24 + drilled
-Fast flow tap
-Undrilled air filter (I had lean condition issues with a drilled filter on the old setup)
-SIP Road 3

Initial carb stack:
140/BE3/128
55/160



Now it feels like I just need to do the whole jetting rigamarole whilst running in the new cylinder kit. It seemed pretty boggy throughout the throttle band, but this is the fun part. Wondering if I'm stifling myself with an undrilled air filter.

Thanks for all your tips and guidance!

Not that you should necessarily follow my lead, but with my much more mild Super G setup (in my post signature), I could not get it to run well at all with any carb mounted air filter, drilled or not and deblued or not. I eventually tried no filter and it immediately sprang to life and ran excellently. I ended up putting a UNI foam pod filter on the end of the airbox in place of the bellows, but later I put the bellows back and just put some filter foam on the intake under the seat.

Maybe I'll go down that road as a last resort. For now, I'll run through the usual process. I'll reconfigure to a 120/BE3/135 + 55/160 with a drilled filter and run through main jets until it's happy at WOT. It's a little tricky because per manufacturer I should keep revs below 5K for a while to run in the cylinder.

What are normal temps for an aluminum kit? I tried to keep it under 300F with that cast iron DR.

Update: Got to 120/BE3/125 + 55/160 and it seems pretty happy for the time being (not ripping past 5K RPM). Might go richer on that idle jet to like a 50/120 and see how she goes. Just need to ease the new cylinder in before I go crazy, yeah?

160/BE3/125-130 down from 130 with an un-drilled (stock P200... could never get the blue one to work over time) filter worked on the three 177's here. Any more than that I'd suspect something else is up, mostly an air leak but it could be a few other things.
I've tried EVERYTHING.

Keep in mind that an un-drilled filter is also an air corrector/flow stabilizer. It will be difficult to jet an un-drilled filter with a smaller ac, assuming your jets are actually what their stamped #'s are (which is another story).
Good luck!

Just FYI.
On my VMC Super G with Polini exhaust, 24/24, drilled filter, Mazz crank I have 120/BE3/125, IJ 55/100.
For cold weather I use 128 MJ and for long highway rides I use AC 110.

So far, all good in the neighborhood with the engine. Still bedding in the rings, which is excruciating because I want to go fast! Question though: it's got a two-year-old stock clutch basket. Is this thing going to just straight-up open like a flower and frag the engine once I'm allowed to crank it to higher RPMs? Is that a thing that truly happens? Are those stock baskets with the band welded around them the best insurance policy?

More for posterity than anything (it won't be going into the engine), check out the spindle I got back from the folks at PCBWay. They nailed my CAD file almost perfectly. If I could have had the alloy hardened, it would be perfect.