Modern Vespa

So are Stella cowls different than PX? I have tried fitting the "bumper" (what is the name for this?). The body isn't in the best shape but it does go on well. The Stella cowl misses the indent significantly. The px cowl I have is much closer but still hitting at the bottom of the indent even without a rubber on. What gives? It looks like the bottom corner of the cowl might need "adjusting" by bending it up?

That is some "crack". Reminds me of the Black Knight from Monty Python - "it's only a flesh wound!"

I kind've feel like you've answered your own question here

Well is it better to try to adjust them or to use an alternate "bumper" solution?

I don't have a good answer to your question. The bumper on my Stella self-alternated a few years ago when I put a jack stand under it one time too many.

How goes the air leak battle? Is that finally all good?

I took the engine apart but had no time to work on it yesterday. The cowls - I think I need to dry fit it all before deciding which ones to paint. If the corners need tweaking better to do it before paint.

We are trying aviation form a gasket on the case gasket along with very careful placement of the gasket….

Still loses about 1 psi per minute, better but not good enough.

Time to order more case gaskets…

so next up is either full case gasket with motoseal or again with aviation form a gasket + RTV at the top. Every RTV I saw in the auto parts store said not for use with gasoline though. I'm thinking I'm gonna have to break some rules here, that joint literally sucks. I'm leaning towards the RTV - I want something with body that can take up any gap and harden.

Per someone (ginch? Craig?), When they say RTV is not for contact with gasoline, they mean for things like sealing a fuel tank.

I've been using it in these situations for years without issues.

ok so rtv definitely for the t-joint, what do you like on the rest of the gasket. I know it's opinion here, I'm usually for hylomar or aviation form a gasket.

I use heavy grease for the rest of the gasket. Maybe I should up my sealant game, but it works for me.

grease is usually ok, I used it on the first gasket here . If you have any questionable surfaces, the hylomar or aviation form a gasket will perform better. I just put 2 more stella gasket kits in the order bin and hit send to scooterwest. I'm too lazy to go pick up so I paid shipping. It's crazy that no one sells the case gaskets for Stella alone, you have to buy the whole kit.

Catching up a bit here....

Cowls: perhaps the stella cowls need adjusting to fit with the rear bumper. They look to be sittiing too low. The rear locating pin gets bent, and may just need some tweaking. I've never noticed a difference between the PX/stella cowl pressings.

** I have an extra set of Stella cowls if you need them.

Gasket sealers: the endless debate, just like oil, tires, etc. Everyone has there 2cents, so here is my 1.5 cents worth. Use the RTV to seal that surface and build up material. It will hold up fine. Hylomar works well too, but doesnt build up thick like you want. I use the Hylo on intakes, sometimes on cyl bases and it does the job. Permatex makes a motoseal gasket maker that is fuel resistant: # 29132. I've used most all types of gasket sealers, from grease to whatever else.... they all work in one way or another. I believe that cleanliness and careful application are the key factors in a successful seal. Clean the surface with acetone really well. then clean it again.

10 psi goes to 9.5 after 5 minutes, not able to get any bubble action at the sealing joints. I think we made it. Probably some leakage by the rings, new rings and new honed cylinder but it's used stuff.

I feel so dirty using RTV, but you gotta do what you gotta do .

Actually I just figured out it was regulated at 9 psi, good to go!

W00t! Glad to hear the leak gremlins are banished!

If it feels dirty but it works, it's not dirty.

I didn't remove the "cross bar" from the gasket. Do I need to worry it will tear and cause some problem? Id hate to take that reed valve off now…

No need to worry. It'll probably stay put, and if it doesn't, Aluminum and Steel beat paper (but not rocks, circlips, or washers).

Ok good, I worked out my tdc and timing marks tonight. Found I'm missing the lock washers for the stator but did get 3 new screws for it, will hopefully find some at work tomorrow. Upward and onward.

I have only undrilled air filters, should I open the heart for this stock-ish setup? Is a stock Stella filter drilled or not?

Was ready to install my engine today but looked at the metal under there and figured I need to rust treat. I have the Eastwood fast etch but ordered some owatrol oil. While waiting, I figured I'd have a go at this cowl. First try with the hammer and dolly, it's coming along. A bit more work with the coarse grit before filler.

Cowl is looking good!

Hit it with the 320 grit and lay down some primer.

I need the weld sorted and definitely will need skim coat after the etch primer. Still some minor rust, probably throw down some Eastwood fast etch to sort that. The back side needs attention too, but I care far less about perfection there.

Back at the cowl again. Front is cleaned up as it will get, but I need to see if I can get someone at work to weld that tear next. On the back, I got all the loose stuff and I'm planning Eastwood fast etch for the surface rust.

Once the weld has happened and the fast etch, on to primer after some 150 and 320 grit prep. Maybe that prep belongs before the fast etch??

Cleaned off more so that the whole area getting filler is to bare metal. I'm using shade tree cheap Bondo, it's instructions are for filler to go to bare metal. A bit of Googling shows this is a hotly contested area. Some are passionate that filler must go on bare metal, others just as passionate that it must never do so. I'm just gonna follow the directions.

I didn't go to bare metal when I filled my GL. Even the bits I did when I went to bare metal I did over the Direct-to-metal (DTM) epoxy primer. It all seems to be holding up this far.

My research mostly indicated that if you can, either do a full strip down to bare metal or minimize the amount of bare metal because you're probably not going to do a better job than the factory did.

This is primer-filler time, not Bondo.

Well one thing is certain, I will not do a better job than the factory!

It's hard for me to judge, the surface still had lots of hills and valleys but my hammer and dolly skills are such that this is probably as good as it gets. Are they deep enough to warrant bondo? Not sure. It will probably be mostly sanded off but fill the craters. Is that a bad approach? It's deeper than filler primer alone, I think, but could be that glazing putty is the right tool over filler primer.

Primer is a glue.
Bondo is not a glue. It will crack or flake on thin bare metal over time.

So the bondo is ok but you like it on top of the primer? I am ok with a good think on this, no hurries and I need that weld done before I commit to anything.

By all means, use filler and glazing.
But as needed, once you've primed and sanded.
Looking forward to seeing the next stage!

The right cowl will be a cake walk, it's got no tear, the inside has solid paint and a piece of insulation (!) and the dents are minimal. That one will get no attention at all on the back side and just a sand, prime, fill, prime, and paint. For that side I'm using the Stella cowl as it's the only PX style one I have, the rest are tabbed and without the block where the hook attaches.

All better now…

Body filler is essential.

So my plan, taking into account the feedback:

-sand inside and out with 150 then 320
-on the rear, apply eastwood fast etch to convert surface rust
-etch primer on bare metal areas (front)
-filler primer, multiple coats, followed by a guide coat
-sand filler primer with 320 to find areas requiring body filler
-bondo
-sand
-more filler primer with guide coat
-sand with 400
-paint & clear

I think that will work. There may be more iterations of sand / bondo in there, I'm a novice after all. More iterations are worth doing to get it right.

Can anyone explain what part of the latching block for PX/Stella style cowls creates the ground? I'm assuming I need to block off a bit to allow a ground to occur. I know the pin at the bottom carries the positive side.

I think just where the hook is touching should do, eh?

I'd guess that the original ground contact for the cowl was the latch spring, because the holding pin had a rubber buffer on it. Either way, so long as you've got continuity back to the frame, you should be good.

Maybe add 600 grit and green Scotch Brite pads to your list. The latter is very contour friendly.