Modern Vespa

I assumed that maybe these are nuts that do not need spring washers. Any VMC cylinder kits haven't washers and spring washers.
I don't know about piston manufacturer and there isn't any info on piston or the box.
In the past it seems that I read somewhere about it but can't remember now...maybe FMP have some info.

More parts is coming.

So nice marmitta Polini Original...


But not so nice as same exhaust for V-range. Left - V-range, right - PK. Seems like Polini Motori not like PK and its owners same as V-range. I mounted few Polini Bananas(classic and righthand) on PK and it always was terrible - need to bend, cut, reweld, cut chassis or even all together.


On the other side - nice exhaust with stiff machined joint.



Top - V-range, bottom - PK.


Fits like a glove(V-range pipe on V-range engine)

Again out...


...and on the table.

Engine almost stripped down.
Mounted cylinder to see what to do with ports. Not too much.



Also was surprised when saw gudgeon pin. It is original Malossi part which worked for near 4-5K km. Needle bearing have no any marks. Very strange.

Spent few hours in garage.

Need to cut this edge to fit the cylinder.





Here need to cut too.



Done.



Ports done.




Clean.

All bearings is in. Same as kickstart rubbers, kickstart o-ring and vent screw.

I've wanted to get a Primavera 125 for a small frame till I saw Snowball. I normally don't like blinkers but yours look great on there. Love the work you're doing. Blows me away when you post pics riding in the snow!😄 The pic of you with the scoot in the back of the car is priceless too.

I amimpressed by how you clean up your parts. I judt rebuilt a px engine which is not half as clean…

I always worry that some dirt will get inside and spoil something. I think it can be called a phobia Thanks Rob! First similar photo was taken with 50 Special i 2017. Then my few friends also did same.






And photo with previous owners.

Love that! Awesome!!

Things went good...


...until I moved to primary drive cog. It is SIP primary gear. When I tight the primary cog nut crankshaft is blocks.
It turns out that cog have incorrect teeth profile SIP cog also have a smaller protrusion on bearing-side compared to DRT cog. Well I got what I paid for. Thank you SIP.





I praised this SIP primary gear too early

Few hours ago I was in the garage.

Gasket from local shop. They can make any gasket personally. It is cheaper than SIP Premium blue gaskets and much quicker and in the same time better quality material. I pay only for biggest gasket and all other gaskets which can suited inside big one is free.
I used this gaskets few times and never with sealer only light layer grease(or even without). Never any fails.






For intake manifold I used this fancy SIP Performance gasket and will see if it really don't need any sealer as SIP says.

And now is question time.
I use SIP 152mm cylinder studs. And them can't be screwed full into cases.
Do I need to cut them(only 5mm is needed) or I can use as is?

you probably need the short studs (145mm or something like that if i remember right, for the 130cc kits)

I dont think cutting them would be a problem.

Excellent work! I am a clean freak too. It comes from working on automotive engines with sleeve type bearings. Really easy to have trash go through the bearing from ordinary dust and dirt. Vespas also don't have oil galleries that accumulate crud at the ends as well as metal shavings from factory machining. This stuff tends to let go when a freshly rebuilt engine is first started. Granted, it would have to be really filthy to wipe a bearing.

Vespa engines seem a lot more forgiving, but cleanliness becomes a habit and you can never go wrong by being too clean.

Studs was cut and I start to measure the squish. But I met a problem. OEM Mazzucchelli pin bearing turns too tight to SIP pin. I was bit confused but then remember that I have few bearings in the spare. And Piaggio FC2 bearing fit perfectly.


I was need to sand down cylinder head a bit to get the 1.4 mm squish. There is no any manual for SIP cylinder but as long as it very similar to VMC GS I went with VMC manual.

1.32 mm with 0.3 mm gasket. Then will be ok with next 0.35 mm gasket.


Done.


I tried to mount an exhaust and "wow it fits PK engine without any bending, cutting or welding!" Well need too look how it will fit into chassis.
There also lot of space around wheel and it seems that stated 3.50 tyre compatible is true. And I even can pop in rear hub cap! BTW on the photo rim is not seated fully on its place, so there should be even more space.

New day - new problem. Figured out that flywheel rests on cylinder fin and can't be mounted. Did some measures and it turns out that it need to cut 8.5 mm from flywheel edge, it is almost completely.



Also here a good news. Primary drive gear machined and it fits as it should.




And changed rear shock rubber mount.

I've cut numerous bottom fins off cylinders like that to fit them onto LML cases. If it makes a difference, I've never seen it.

Build is looking good and will be a fun ride

I ran 3.5x10's on my Smallie for a few weeks until I was able to get 3.0x10's, and had no clearance issues.

I really like the 3.0's on it, though. They feel super-planted and also really good at high speeds.

I would also cut the cylinder fin…

Great thread, great pics. Enjoying your build.

Thanks guys!
PK will stay with 3.0 for sure - I have 3 tires in new and almost new condition. It was easier for me to cut flywheel lip.
Already done.
Maybe bit too much but 3 mm of lip is still present. And photo is taken without flywheel nut so maybe it will sits deeper.

Now I want ask about ignition timing.
What value I need to set?

Static timing, right? 18 BTDC at 4,000 RPM's

Yes, original ignition. Thanks Chandlerman.

With all the cutting youve had to do, would you still recommend the SIP Travesi cylinder or go with a different brand? Polini racing?

Engine still on the table so I can't say anything about it performance.
I hope that this cylinder must be more powerful than Polini as it have modern ports layout(how advertising states). And obviously more leakproof head.

I'm tried on mate's PK Polini Mono with Mazzucchelli racing crank, SHB 19.19, Polini Banana, Vape Road and can't say that I was very impressed.

About cutting I can say it is my fail that I'm not checked cylinder to flywheel before assembling. It is absolutely not a problem to cut fin on the cylinder. And obviously not so much cutting as here.

The price was also important for me. I got this SIP cylinder for $131 while Polini Mono is $248.

I want to jump in on behalf of the Admin and Moderators to announce a well deserved forum award. This thread has so many wonderful and detailed pics, creative solutions, and quality information in the pics alone...(and it's a PK!) that the MV Documentarista award is hereby bestowed to Roland for his efforts.

Thank you for taking the time to document this build in such detail!
We all look forward to seeing how it all turns out!

/Round of applause

Wow! Thanks!

👍😄👍

Love it! Well-earned, Roland, in this and all your build threads.

Good documentation should always be recognized and awarded

I would be very happy if someday my documentation will help someone.
I remember when I got my 50 Special and know almost nothing about geared Vespas and there was days or even month of surfing thru internet in searching of information.
I found lot of very nice and helpful threads with photos on different forums(idk why but MV very quickly become my favourite) and videos on youtube.
Hours and hours of reading and studying.

I want to thank again all of you guys who helps me here with my often dumb questions.

Everything seemed to be going well but then I couldn't hold brake plate in my crooked hands and dropped it on the floor. Cracked.


Was upset but then remember that I have another one brake plate from original PK S engine. Only need to good clean it and put in new seal.
I noticed before that brake plates is makes different(similar story with clutch covers too).
991815 3C - it is from PK 50 HP, produced after 1990
991815 2B - original PK 50 S, 1981.




The main difference is that HP one have addition rib and another shape of cable adjuster mount. Also HP have noticeable worse finishing.




HP


50 S




One more difference is cable holder. PK 50 S one with two holes and can't be mount on PK XL crankcase.

So I successfully changed the brake plate and move to the clutch.
Today I finally received parts that were missing to install the clutch.
- bottom base plate
- DRT push rod
- SIP actuation lever


Fresh Newfren clutch plates kit


I also had new Polini Sport spring on the shelf.
And here the problem starts. When I took out spring from bag it immediately seemed too high and bit bended. I mounted same springs few times and never had any problems.
Left - used Polini spring, right - new one.


It was absolutely PITA to compress it to be able to assembly clutch with basket installed into primary.
But I did it.
And it turns out that clutch lever need absolutely brutal force to engage it but in the same time clutch stays almost locked.
Old Polini spring seems too soft so I take new one from Newfren clutch kit.
And assembled clutch without any problems.
Now clutch lever needs absolutely normal effort and clutch is clearly disengaged.

I have had problems with this clutch before and I suspect that it may be because it is assembled from completely different parts.

No pinion gear clutch plunger? You're going to wish you had that.

I'm clearly understand what you talking about. I tried XL2 clutch and even with uprated springs it is absolutely nice. Also my P with Cosa clutch even better. So soft and easy.
On the other side clutch on my Special with Polini Wave spring is absolutely nightmare but somehow I got used to it and even in city I have no any problem riding all day long. On PK there was clutch with 3 plates and Polini spring - much more comfy than Special. Now with 4 plates it must be a little hard. Still not a problem I'm sure.

Crimaz plunger require pressure plate with bearing then it maybe will need clutch cover spacer then two gaskets and longer bolts then brake plate spacer and maybe hub spacer and maybe some grinding etc...
With this PK(and with my other Vespas more or less) I try to follow the path "if it's simpler then it's more reliable". And easier serviceable.
Oh and cheaper for sure

But I'm seriously thinking about Egig One Finger or VMC Hard Work clutch for Special.

The egig one finger is nice, but can only handle 28 HP, which is why mine now lives in Canada with Jordanaitor.

I love the pinion gear plunger. I was deeply disappointed that it failed in my GL's motor. I think it needs tighter tolerances than my LML clutch cover could provide, though.

I don't think it needs so much, the spacers depend on what primary basket you use.

The DRT baskets definitely need the clutch cover spacer. Ask me how I know… lol

For the pinion gear clutch push rod, there's 2 sizes… (also ask me how I know…)

That push rods is for XL2 clutch cover. So also requires XL2 clutch, XL2 pressure plate, XL2 clutch lever.

My PK have V-range clutch type with single spring and same clutch cover and other bits.

Ah sorry, I thought you thinking of (or wanted to…) using the XL cover but didn't want to because you're not using a clutch with a bearing pressure plate.

I'm thinking of going budget like you Roland, for the 112cc build.

Initially I was thinking of investing for the future, fabbri, vmc blah blah blah…

But it's actually a lot of $$$. Especially when I could be upgrading the 170 engine

But with basic sub 15hp parts, I could rebuild for less than 300euros.

Need to buy, crank (was thinking of going Reed, but will stick with rotary), primary, clutch, exhaust…

It's tempting…