Modern Vespa

Squish is set and tope end sealed up. I used a 0.3mm base gasket + 1.5mm head gasket to get the squish right at 1.1mm. Light skim of Yamabond on the base, and a very light skim of Copper RTV on the head. I'll let it cure overnite then its Leakdown test time.

Well.... air leak down test failed. The clutch side crank seal leaks on the outer edge. Which means I get to break it all down again, and replace that. While I wait for a new seal to arrive, I'll keep busy with other things...

I'll admit that I believe this to be builder error. As we know, there are 2 types of clutch side seals for 2 different types of cases, rubber edge and metal edge. I'll admit that I have used these 2 different seals interchangeably in either type of case, without issue before. I know I know... it's sacrilege, but if it works it works. This time it obviously didn't work, so now I wait for the correct RUBBER edge seal. Lesson learned

The exact reason why I stock both types on my shelf at home

I started using locktite 603 after a new seal failed. Sometimes they just leak.

Great for metal seals. Much less good for all rubber!

I also used 603, but still leaked. A new proper rubber seal should do the trick.

Well…..since I live in Oregon, when it rains it rains and rains and hails and rains then dumps out like Hurricane Harbor. Or however that saying goes.

My new rubber seals arrived, along with a variety of cylinder gaskets. Thanks to Qascooter for the backup assist from his personal stash.

I got down to splitting the cases to fix my not-so-rookie mistake. I got all the gasket surfaces clean, and old seal removed ready for install. When I noticed something…not great… a tiny crack near the rear intake stud hole. Further inspection confirmed, there is a crack running vertically along the hole.
Even further inspection revealed paper thin aluminum, which opened up into a void. Nice.

This was already previously repaired with a helicoil, which has heldnup fine for a while, clearly no longer. That rear stud is 50% of the holding power, and if it wont hold a thread, it wont seal. and I think this thing is toast.

Damn dude - that sucks! Are you going to have it rewelded?

I'm not sure yet, still processing the new data. Re-welding also means re-machining, tapping the hole and decking the surface. Which also means much more time, as I'd have to send it out. Plus, I am less confident about longevity.

Although I hate walking away from something like this, I could go nuclear and swap the cases for another set from the stash. These also already have material added for a big reed. The pad wash thrashed, otherwise cases are untouched as far as porting.

Damn man, that stinks!

I'm leaning towards Camp Weld too. My biggest concern would be cleaning the heck out of it first to ensure minimal porosity/inclusions and best penetration.

Wow sucks about the cases but better to find it now than further down the line. And so great you have another in the stash! It has provided

Collecting (aka focused hoarding) does have its benefits. I was kinda saving these other cases for another project, but nothing specific; so I guess this is what they are for

MF! Definitely not enough meat to support a stud there. If it were mine I'd weld it up, leave it proud, tap and helicoil. Any welding will be softer than the original casting so extra metal will help and hopefully won't change performance enough to cry about. My 2c.

I agree. Although anytime I've had welding done in this area the gasket surface has warped. Hard to tell till its on the mill being cut

That's the bummer part, definitely going to be some warpage after welding. Nature of the game. These crazy scoots have us by the tonsils at times. And people say boats are money pits. At least my boat feeds me if I do my part.😁

So…. I did a thing

For the record, I'm not completely abandoning the old cases. They are simply moved to the Deal with Later pile.

Those look amazing! Congrats and good call

Wooohooo! Now this is getting really good!

I think you made a great choice. My decision to buy the same case was easier as I didn't have a case to start with. Even if I had an ok spare stock case, I still would have considered it worth it.

I think so too. I'm tired of messing with the cases which all have issues. I'll see about fixing those for some future use.

Good lord that's crazy town! Good on ya!

This is definitely in the "pay once, cry once" territory.

Which top end will you be fitting on this one? Keeping the Malossi Sport ?

100%! Keeping the Malossi Sport, 60mm bell crank, RD reed, 30phbh carb, efl gears, etc. Basically just moving all the internal components into these new cases.

This is pretty much the combo I'm finishing up. The idea was something that could operate in the upper limits of the stock engine for a prolonged period in a reliable way. None of the components really push the performance envelope, but are all proven and have been around for awhile. Lots of feedback around from folks who have successfully set up similar combos. Hard and soft replacement parts are easy to find.

Of course, I enjoy following along with the newest and fastest. But at this point along the Vespa learning curve I'm happy to leave that to the more experienced and adventurous builders among us.