Modern Vespa

I can't seem to find any info on this kit at all, I need some information such as what torque spec for the 8 nuts, do piston rings need a specific presentation? (Trapezoidal?)

Are the ring gaps already correct? If not what should I be looking for

As with all kits, one should check the ring gsp is correct for the postpn being used. There is a formula for working it out. I'll have a look for it and post it here.

Torque spec on the bolts. Use the appropriate spec for the size of thread. The vespa manual has it listed for M8 and M7 cylinder... 200cc and 125cc respectively

Thank you I'll have a look, I didn't know where to start

TORQUE SETTINGS TABLE
https://www.engineersedge.com/torque_table_sae.htm

RING GAP CALCULATION
https://wossnerpistons.com/pages/ring-end-gap-calculator

I hope this helps

Please post as a project fitting and setting up the kit and any performance mods you make as well... also how it behaves in the real world would be a bonus to read also

I'm considering one of those kits and would appreciate knowing all the above before I dive in 😀

The 4 hex bolts are M6 and the standard 4 nuts are m7

Do it to the spec of the M6 so you don't strip them with the M7 torque.

Here it is.

Your a lifesaver, thanks mate.

Couple questions, Do you run the 3% fuel mixture when running in or all the time, or simply the usual 2%. Also I assume as it doesn't mention anything about setting ring gaps it is all to spec already? When you test the squish, do you torque everything down to spec? Sip states the recommended ignition timing is 18 BTDC unlike the 16 in the manual

3% for the running in. Then 2%.

From 0.2 mm to 0.3 mm is ok for ring gap. It is worth to check. On my VMC GS 125cc kit wrong rings(from 135cc) was in the box and I need to file them to fit Yes. I have 18° with my SIP kit.

Awesome, really looking forward to running, I ended up with choosing the Leo Vince (same as polini but I think it looks sleeker as there is no logo) which is not the best exhaust but is solid, and standard 18.18D (will upgrade along with manifold in future, currently upjetted to 45 idle and 92 main which I'll work down), the cases will remain unported. I am not looking for huge performance as I'm in a city and barely going over 40 but gives me options to upgrade in the future

I think you will like your build anyway. It is really good cylinder.

IMHO it is fun to try all with small steps and not get all in one.
I had done this way on my Special:
75cc > 19.19 > 102cc DR(unported) and Polini Banana > Ported > VAPE Road ignition > 102cc Polini > 125cc VMC and PHBH 28 > PHBL 24 > EGIG 170.

Can the rings be installed in any orientation or are they trapezoidal?

IIRC rings marked with "R". And must be installed marked side upward.

I assumed so

The rings are perfect spec 0.2mm out the packet squared up at the top of cylinder, this is the lower limit of the tolerance so proper wearing in is essential with really carefully riding. The ports definitely needs smoothing and casting a bit rough , lots of sand also inside the piston, any tips to clean it out? I don't have air compressor and I also feel like the factory oil will make the flakes stick anyway

What I do is the following,
Wash it first in a de greasing bath,then flush oit with good old water from a hosepipe. Then I get the heat resistant paint (matt) meant for wood burning stoves and spray the outside of the barrel.

Then assemble

Hope this helps you

After smoothing out ports, I'm gonna use some pipe cleaners (plastic) , cloth and acetone , then hose with dish soap while agetating the surfaces for loose debris, dry very well with heat gun especially the threads then should be good, will do same for piston / head as it also has sand everywhere for the coating

Roland can I confirm the squish is 1.2mm from the edge of the piston and head? Also do you need any locking washers for the head fastening, none are provided. Is silicone needed for head gasket?

Thinking hylomar blue would be sufficient for the head

I use washers and spring washers. Copper silicone is what I use.

Not wishing to hijack this thread, bit can you expand on why copper silicone is better for head sealing over other methods. I'm eager to understand and adapt my engine builds if it's a better product.

Typically I lap the joints with a fine compound. or wet.and dry paper first if it's particularly bad. Then use hylomar.

Eager minds want to learn a better way to do things

I just got permatex copper ultra silicone so should be good for both head and exhaust ghaskets, the. I always use hylomar blue for base ghasket/ intake

When I started to learn about "how to" this Vespa engines I just read somewhere about copper silicone for head and exhaust gasket.
I tried it and it works perfect so I always use it.

Do you use the copper silicone sparingly? Just enough to cover the aluminium ridging on the head?

I use this stuff and it's tacky, seems like it has a silicone base. Spray is convenient and it's easy to mask off places you don't want it to go.

yes just a little smear

I have just noticed the cylinder included does have some imperfections on the inside of the sleeve, it does not show up on the outside but doesn't look nice , did your come looking like this?

Looks to me like there was either some grit or similar in the mould or it was a trapped air bubble when cooling down.

I don't see it being much of an issue either way.

If it really grates on you and you are not happy to run it, get in touch with whoever sold it to you and ask them to send a replacement - checked before despatch

It does look like manufacturing damage and goes quite deep considering thickness of skirt

Send it back if its deep... surface isn't really a problem

To be honest, I don't remember what my piston looked like, but it seemed fine. I wish I would have noticed something unusual.

I only have these photos, and looking through the intake port, everything looks fine.

And I already done on it 3000+ km without any problems.

They are definitely casting imperfections, thus shouldn't get worse from heat and pressure but I'll see if I can get replacement anyway, I'm in no rush as I'm getting my frame reinforced