Modern Vespa

Uh.
What's this?

oh gawd. please tell me it's some schmutz and not a crack...

Keen eye.

Mostly just oil crud though…

Cleaned up with a wipe of a towel.

Listened again to your squeak.
So strange.
Certainly sounds like rubber rubbing.
Have a theory of everything (TOE):

Considerations:
- Crank appears to have scraped in the rotational direction.
- But also there are signs it scraped as it was pulled in - see perpendicular striations
- Mystery swarf inside of motor doesn't seem normal
- Motor sounds like it swallowed your dogs squeaky toy

My hypotenuse:
- Main bearing is or was not square when installed
- One of your main seals was dragging - swarf may be related and comes form seal's metal if it has any

Treatment:
Maybe replace main and seals just in case.
Definitely pressure test.
Check inlet pad for scratches and skim coat as needed.
Get second opinion - they would never have hired me at sloan kettering.


Some gouges occurred perhaps when it was assembled

Thanks everyone... it takes a village... especially when you're the idiot. (I'm pointing at myself there.)

I didn't have trouble closing the cases, which I would have expected if the bearing wasn't seated squarely? It also opened up easily enough and the crank came out w/o any issue? I really am puzzled here.

Someone asked about the crank condition... it's clean and nothing that looks amiss. It does have staining on one edge that probably was facing the carb opening for many years. But nothing that scares me. Will try and post some pics later and get ya'lls thoughts.

Ned , as far as the pad goes. It's clean. Maybe a tiny area of a mark but nothing that you could catch a nail on even.

Plan of attack: I'll pull the seals and investigate the bearings and races.

More soon.

A "Most Vintage Vespa Statement Ever" nominee right there.

those "gouges" look like they predate the cleanup machining done after casting.

*snickers* If the squeeky case fits... Thank you for that. Made me go back and look for pics when I spilt the case originally. I think you are right!

You can just make them out...


Makes me feel a little better.

Well... the drip, drip, drip, of the repair treadmill continues. Hmm maybe that drip, drip, drip is the sound of my tears falling as the saga drags on...

I tore down the engine again, replaced all the seals, (None of which looked abnormal.) put it all back together and, still not holding pressure.

The search continues....

I'm tellin' ya...smoke test...it'll find the leak every time.

Yeah, probably a good call ese.

Hmmm... I've been lurking, waiting for the other shoe to drop with you finding the source, it all makes sense and all is right in the world.

You say it's still not holding pressure - slow leak, medium or pretty fast? I second Chandler's suggestion, it sure made solving my smallie leak and checking afterwards easy! Fortunately leak was at the manifold but not obvious, so it was a simple fix once located.


I cheated and didn't have to make one, I borrowed a pro smoke machine from my pro motorcycle friend.

Easy hookup on a smallie, just this and plug the exhaust header with a wet rag

Some mysteries got Agatha Christied today.

Mark asked me if I smoked?

"Why I do smoke on occasion Mark. Why do you ask?"

"Well," he replied, "there's your smoke machine."

So off to the bodega we went. Then I shotgunned the cigar (pic below) through the innertube into the exhaust stub.

And well… we found the squeak so to speak. It turns out …due to the case cut of a rally 180 that fiber glass spacer is critical.

Now we are off to see if I have one of those damn spacers somewhere.


https://youtube.com/shorts/0TuVwLUugU4?feature=share


89 cent smoke machine

Interference with airbox sans spacer.


Last edited by Birdsnest on Wed, 24 May 2023 01:48:30 +0000; edited 1 time

I am shocked… SHOCKED… how well it ran without the spacer.

Hilarious and now I must confess that I found my leak the same way, but used the machine later to test and verify that all was well after I was only pretty sure I'd fixed it. But I can confirm that your way works just fine.

So…. Leak is way better but not solved. It loses pressure over a few minutes.

I used a real deal smoke tester (not my cigar shenanigans) and just don't see any smoke leaking from anywhere?

Recap -
1. Rebuilt and ran well but couldn't get that nice low tick-over

2. Developed a weird squeek when kicked over

3. Lots of diagnostics with the engine insito before pulling.

4. Split cases again and all looked good.

5. Replaced seals anyway

6. Cromag style smoke test revealed the bake light spacer is 100% needed on 180 cases and probably the cause of the main leak and previously mentioned squeek.

7. Holding much better pressure but still looses air over 5 to 10 minutes.

8. Got the SWEET MJ Rally blank (Thanks Malcom!!!) … and then ran a real smoke test with a real smoke tester and do not SEE any leaks, but still looses pressure over a few minutes.

9. Anybody with ideas?

10. Scooters are stupid. (Still love them.)

Assume you are on the bench - no a stand.

Leak is limited.
Don't want to tear apart (again).
My suspicions/approach would be:
1. leak between cases at the thin area around the crank. Test - pressurize then rotate motor upside down - spray soapy water so it fills the oil breather cap. Spray soapy water at base of clutch arm where it enters cover. If your leak is either clutch seal or case mating internally - it will show up here.
2. Do same with soapy water at Malcom's sealing plate - not that Malcom's sealing plate isn't awesome! but because there could be some warpage or something occurring there - so check it out.
3. Other usual suspects - cylinder to case, head to cylinder, cylinder studs at head nut, exhaust. With each of these - orient the motor so the soapy water wants to kinda sit up on the surface - then rotate and try again. Use air to dry the crap out of it after if you have an iron cylinder. Then spray it with WD40 - or just do that prophylacticly - to avoid flash rust.

Odds:
Case mating internal at clutch - 3:1
At or around blanking plate - 5:1
Cylinder base 10:1
Testing system itself - 1:1

🙂

Good luck!
Let us know!

Put me down for $10 worth of no longer usable Dave & Busters tokens on it being the case halves.

Welp…

I made incremental improvement. I think at this point some of the air leak is the pressure test equipment and then a microscopic bleed somewhere on the engine. It holds between 100 and 120mm hg for 7 to 8 minutes on the engine. I can maybe double that on the pressure tester closed on itself.

At this point I am gonna send it.

Hat tip to Ned and Mark and everyone for help.

Mark asked if I remembered to cut the "nibs" off the gasket. (The little flaps by the cylinder.)
Ahem. I never have! Lolz. 🫢 So, off came the cylinder and I excised the mashed nibs with a razor blade.

I think it made a difference. Thanks all for all the help.
Onwards.


Got Nibs? Just say no.

Send it!
Launch it!!!

ship it!

it's a short week and all, but I expect you to be riding this around for donuts on national donut day!

(it's Friday)

Squeekless in Seattle H-town!

What a week!
Blindly purchased the wrong speedo for a fraction of the thousands of dollars set for your minimum…,
And now this!
Awesome.

Imma go buy some scratchers when my paycheck clears!!!!

Silence of The Spanish...

Muy Bien!

Quick bit on jetting for myself or anyone searching stock or stockish rally 180 jetting

20/20 carb
SiP rally 180 can
Was running 160/be3/108


Was losing power and flat at points of the main jet when WOT.

Moved up to 110 felt good (110 bc was handy, also book says BE2, but I can't find one in my parts pile).

Plan to drop in a 118 and work down.