The SS Minnow - Vespa PX200E

[GT6MK3]

I almost feel guilty about utilising a work table to do this.  But the MD has completely farked the install of our new roof by using a useless mates company to do it.  A two week job took 8, and yesterday they finally reconnected the aircon to my office and the server room.

Today when I got in I heard the sound of an aircon water purge pump running, the worrying sound of water falling into standing water within the internal false roof, then had the sight and sound of water running out of the vent above me all over my desk and workstation.

Unpleased would be a polite way to describe me.

So I still couldn't use my desk this evening when it was time for this to happen...

 

[Nick Jones]

Taken from the security video camera?  (UK in-joke!)

I see no reason for guilt, more mess could easily have been made eating dinner and everything left sparkling.....

Full rotation now I trust?

[Hamish]

That’s a great video 

nicely done. 

[rogerguzzi]

Hello Craig

                   You made it look easy but how long will take you to wring its neck and brake it?

Still it will be fun while it lasts and I think to a greater or lesser degree we are all the same it just depends on the depth of your pockets!

Roger

ps it is easy to be steady and safe!

[GT6MK3]

There’s no doubt I’ll break it, the challenge is hitting the sweet spot in the speed vs reliability curve.  I like to think that the better I build it the further into the curve I can lean. 
 

Today’s efforts, lots of dry building to get measurements.

First getting port timing measurements with the crank, cylinder and base packer in

Then measuring and adjusting the squish to near as I can to 1.35 mm.

Started at 1.15mm. Adding a .4 gasket to the base packer then torquing it down got me to 1.365.  Close enough, up to 1.6 is acceptable. I’d prefer not to have a paper gasket in there, but in this case it will basically be a carrier medium for 2 thin layers of hondabond, so it’ll be ok.

Still need to gap the rings. They're currently at .18mm. I'm assuming .004" per inch bore. Bore is 72mm, so 2.83465".
2.83465" x 0.004 = 0.0113386".
0.0113386" = 0.28800044mm

So I'll be out with the file and aiming for over 0.275, and tight at 0.3mm.

[GT6MK3]

Playing with the base gaskets got me down to the ideal 1.35 squish.

Port timings are critical for performance with a 2 stroke, so I'm trying to be sure I've got these right.

2 methods, so I can compare the results.

Method one using manual measurements.  A vernier needed to be sacrificed to fit down the cylinder to get the port depths.  Introducing a vernier to a cutting disk seemed extreme, but necessary.

Having measured the exhaust at 36.6mm below the cylinder, and the and intake port at 49.5mm, I needed to figure out the rest of the dimensions of the various components.

This is a pretty bespoke build, with an overstandard stroke crank, a longer than standard conrod, packers top and bottom of the cylinder, and a head that protrudes into the bore, so the calculation is a bitch.  Lots of precice measurement needed, like getting the depth below the cylinder height of the piston at TDC without the packer or the head in place (0.3mm).

It's head spinning maths

At the TDC the piston is .3mm lower than the cylinder.  

There's a 2mm packer between the top of the cylinder and the head.

The squish band of the head protrudes into the packer 0.95mm, so there's 1.05mm between the top of the cylinder and the squish band.  That checks out because there's 1.35mm squish, as checked by measuring solder squashed in place.

That gives a calculated exhaust port depth of 37.65mm, intake at 50.55.  Assuming the bottom of the squish band is the top of the effective cylinder, and the piston at TDC is 1.35mm below that, Blowdown is 25.4 degrees, Exhaust Duration is 179.2 degrees, and Transfer Duration is 128.4 degrees.

There's some rubberyness to measuring these with a set of calipers, so I hooked up a digital degree wheel to do some checking.

That gave me pretty close results.

The Exhaust port opened at 90.6 degrees, the intake at 116.  So Exhaust duration of 178.8, (within 0.4) and Transfer of 128, (0.4 again), and blowdown still therefore at 25.4.

My head hurts.

[Nick Jones]

4 hours ago, GT6MK3 said:

My head hurts.

Not surprised…..

So you have some numbers, taken from the engine….. presumably you have some “should be” numbers to aim for, and hopefully have a match?

[JohnD]

Just thought, Craig, with a little alteration you might get some of the same sponsorship as F1 Ferrari!

[GT6MK3]

20 hours ago, Nick Jones said:

Not surprised…..

So you have some numbers, taken from the engine….. presumably you have some “should be” numbers to aim for, and hopefully have a match?

Yep.  There's some black magic to it all, but the numbers look good for an overpowered, slightly overgeared, fast tourer.

The low blowdown number means torque not revs, but since I've slightly overgeared it, that was the aim.  The 2 stroke guru's I trust (the Vespa world Nick's) all approve.

15 hours ago, JohnD said:

Just thought, Craig, with a little alteration you might get some of the same sponsorship as F1 Ferrari!

 

Suspect you're more likely to get sponsorship than me John.  It's going to be a beautiful engine on the inside, but it's going into a sleeper frame, and will soon look very unlike I hope it runs.

Back when I was a competitive skydiver, I was the team's sponsorship director.  My moto for getting sponsored equipmet for us to jump with was "It's better to write a thousand emails than one cheque."   I was pretty good at my role, ( I suspect mostly because my team mate was a damn good skysurfer who smonsors wanted to stick their labels on).

 

[Nick Jones]

1 hour ago, GT6MK3 said:

"It's better to write a thousand emails than one cheque."

 Absolutely!  *
 

 

*(Unless it’s a very small cheque - natural laziness kicking in - mine, not yours!)

[GT6MK3]

Shiny part # 24 for my clutch arrived today. Unfortunately, because a neighboring state's government couldn't organize a root in a brothel, we're back in a (hopefully) short statewide Covid lockdown. So as a designated authorised worker, I'm only allowed to be at work for actual work.

If, for example, I had a spare couple of hours while I waited for a backup to finish, I'm pretty sure I have to concentrate on work, and ignore all side projects.

So my clutch had to build itself.

 

[Nick Jones]

Oh yes!!

Those levitating tools, that’s bloody spooky….. witchcraft I tell ’ee 

[John I]

I need some of those levitating tools in my garage

[mpbarrett]

9 hours ago, John I said:

I need some of those levitating tools in my garage

do you think they could the missing spanners or the bolt you drop on the floor that immediately disappears...

[JohnD]

It's those garage gnomes!     I've tried a saucer of oil, but they keep hiding stuff.

[Hamish]

Great video Craig. 

[GT6MK3]

L.O.U.C. came out to play today.

I decided during lockdown to order an upgrade kit for the reed valve (more air and fuel in=more potential for mayhem), and all the bit had finally arrived.  Being 3 parts from 3 different manufactures, of course it meant changing out some bolts and making a from scratch gasket, but I was ready for install today.  I'd dry fitted the adapter and housing to the cases, and the reed and lid to the adapter and housing, so it was time to crack on.

Step one was to paint the lower gaskets with Threebond to give a good seal without gooping it everywhere, and start building up the adapter and housing combo.

My aim is to have the base and adapter semi-permanently sealed, and then have the reed and lid removable, so no threebond from there up.  Don't know if it will seal without it, but I'll give it a whirl that way.

Having juggled it all together and torqued it down to 12nm, it was time to fit the reed.

Dho.  That will need some adjustment.  After some very careful filing so as to hopefully have enough sealing area left on the base, it snugged down.

But the lid needed help too.

So out came the dremel and the sanding pads.  Not much had to come off.

Pretty.

It can dry tonight, and I'll see if/where it leaks tomorrow.

[Nick Jones]

That's a pretty big inlet pipe for a little engine........ showing some intent maybe.......  expected bhp?  Rpm?

Seems after-market parts are the same for all marques the world over.... fettling required.  Though as L.O.U.C goes…. It could have been worse 

[Hamish]

That’s going to be a screamer !!!

[GT6MK3]

Given the design and the number of manufactures' parts involved, this wasn't surprising.

Bubble

Bubble

 Toil and trouble

This I could deal with, but sadly there's also an Et Tu Brute issue at the top of the cylinder.

Delicate surgery on that one soon, and I've found an instructional video for the intake leaks

 

[Nick Jones]

How irritating…..

[PeteStupps]

Damn... how depressing. Hopefully easier to sort than it appears 

[socalspitfireguru]

On 7/9/2021 at 3:11 PM, JohnD said:

Just thought, Craig, with a little alteration you might get some of the same sponsorship as F1 Ferrari!

Looks like you have a name sake on the 58 near Tehachapi in California

[GT6MK3]

Oh good grief! I finally got John's joke.  Bahah ha ha ha!  Nicely  done John, and thanks socalspitfireguru.

I have no doubt I'll be stuck beside the road again one of these days, that's half the fun.

A new poster on one of the Vespa forums I hang out at, (who normally only rides modern bikes) asked what you can actually do with a classic 2 stroke Vespa.

My reply was:

"What can you do with a Classic 2T Vespa?

Wow. Lemme think.

I can only give you my experience.

Friends. You can make friends you never knew you didn't have. The kinda people who'll be carrying the thing you really need to get home one day, and really need the thing you're carrying to get home the next. Each will be given with a kinship few people know.

Skills. You can learn skills you never knew existed. The kinda skills that let you build, rebuild, refresh and renew a machine you never knew the working of.

Community. You can be part of a worldwide community of advice, kinship and knowledge that was previously a mystery. This site, and others like it are full of people that want to help, advise, assist and live your joys and disappointments vicariously.

Adrenaline. Till you've done it, no one knows the burning taste at the back of the throat that comes at WOT on a 40-50 year old vibrating, humming, buzzing, and ever so slightly wobbling Nona's shopping trolly that's being abused way beyond it's intended purpose.

Inventiveness. You're going to break down. Where you shouldn't. Where you can't possibly fix it. But you're going to have to, and you _will_ learn to, no matter what.

Engineering. It's Nona's 1960s-1970s shopping trolley. You're going to want to update it. Welcome to the world of re-engineering. Luckily, the MV NSM alumni as an incredibly giving bunch of humans, and they'll help you through.

Adventure. This is the best one. You'll take it places with your friends. Depending on your wants and needs, those places may be as close as the local coffee shop, or as far as the other side of the country. But they'll always be an adventure.

Depending on your attitude, all these things are possible. When I talk to them, riders of plastic, reliable bikes tell me they all have all the things I've listed above. I like to smile and agree with them.

Of all the thing above, when I look at my 2T Vespa adventures, it's the friends, both in person and online that I treasure and appreciate.

Buy a bit of gorgeous, curvy, stinky metal. You'll get so much more than you pay for."

I reckon almost all of that also applies to 1960' and 1970's Triumphs, no matter what we do to make them more reliable.  The Sideways' alumni are an equally giving bunch!
 

[GT6MK3]

Lockdowns pretty much suck, especially in winter.  The vagaries of IT lockdown days mean I sometimes spend days at a time working from home, then stretches of days at a time when I'm stuck in an office 14-16 hour at a stretch waiting for stuff to happen.

I had a long few days in the office the SS Minnow Boss Hog engine is located at this week.  For some reason I'm project managing the build of a new facility for the storage of physical deeds and records (IT = Interesting Tasks for money!), so I'm stuck onsite for ridiculous hours.  

Back to Boss Hog:

The most dangerous leak was the one at the top of the cylinder between the base spacer and the case.  To resolve it without a full cylinder re-install, I loosened the cylinder nuts, then eased the cylinder stack as a unit off the case with plastic spudgers.  With the 3bond broken and the cylinder stack down the studs far enough for access, but not so far as to leave the head unsupported, I re-employed the spudgers to crack the spacer off the cylinder.

To clean off the 3 bond I used Isopropyl Alcohol, carb cleaner,  paper wipes and the eraser on the end of a HB pencil.

Once it was clean on the 4 mating surfaces I took a paintbrush and generously applies threebond, especially in the leak area, then torqued it back down.  No photos, because time was of the essence.

For the intake, after looking at the leak photo's I initially decided to try deleting all the problem gaskets.  The only one that hadn't leaked was the base gasket, I I removed everything but the Malossi reed holder, and spent another hour cleaning sealant off till I was ready to go again.

Then, out with the paintbrush, and a generous layer on the base...

and on with the adapter.  No gasket needed.

Since the last try leaked here specifically (abeit slowly) through the gasket cardboard itself, I deleter it this time.

Having deleted one paper based gasket, I was emboldened to go wild and get rid of them all.

So I painted on the top of the adapter,

and the reed holder

Ditto the top of the reed holder, and the lid of the reed mount.

Then I bolted it all down, look smug, and got ready to leave it for a day.

And looked at the now hopefully redundant gaskets sitting on my desk, and hoped for the best.

 

If you're ever in this situation, with mostly liquid rubber based glue still wet and just starting to cook off, and the whole cylinder sealed off ready for testing, I highly recommend you don't get curious about whether the cylinder is at TDC or BDC and turn it over with the flywheel. If you do, expect to hear a pop and a hiss, and see a dribble of sealant running down the outside of the reed housing...  This will be followed by the sound of you cursing (ahem) yourself.

The only good news is that after you've disassembled and cleaned everything, you can rethink your decision to delete the supplied gaskets, and slather them in  good layer of threebond too.

When your finished, it will all look like this

24 hours in front of a heater to dry, and it proved to be a pretty good sealed vessel.

2 hours later it had lost 12 mmhg, 0.21 of a PSI.  

Time to crack on, as soon as lockdown allows.