Modern Vespa

Ahhhh! Ok. Thanks!!
I managed to make it work without.
Will use next time.

What had me confused - no other parts fit in E - until I took Dremel and sand paper to it…

Thanks Saf.
Appreciate it.

Little help?

Are use the MMW master cylinder on my scooter.

A little bit of research appears to show that the piston, and the accompanying rubber seals, or right out of the Piagio.

I think so anyway.
Historically, Scooter center has told me they don't carry the seals for rebuild. I now see that they have a rebuild kit that includes the piston, for about $70… Seems unreasonable for a piece of rubber.

I'm wondering if this cup shaped seal, is findable, on the inter-webs. Does anybody know what this type of seal is referred to? I welcome any search tags if you have ideas. Thanks.

-CM

Here you, complete rebuild kit…

https://www.sip-scootershop.com/en/product/gasket-set-grimeca-brake-master-cylinder-grimeca-sip_49474800

is that an 11mm?

Thanks guys.

Safis - I missed that when I searched. Helpful.


OCT - Piston is 12MM. Would love to find the cup in the US...

Piaggio also sells it as an OEM part. Maybe you can get it in the US…

OEM code is: 494748

Here you go…
https://www.scootermercato.com/Scooter-Parts/Disc-Brake-Parts/49474800_2

Jesus Safis.

Hahaha.

Awesome!!

Can you help me find the keys to my tool shed? They've been missing for about three years.

How did your seal get damaged?

Good question.
Just basic use.
Second one - kit came with two - swapped first after a year.
Looks like the brake fluid is attacking it?

I have the most unpleasant challenge of bleeding the brakes tomorrow.
Done a full flush.
For the sake of RnD, bought a new caliper off aliexpress.
Tore it down into halves - and shot some pics.
Will post when complete.


More on the "double bleeder" set up when I have it all working/back together.

that piston looks wore the F out. I didn't think it was that old?

I'd check the bore to make sure you're not doing it all over again in short order.

I have a master cylinder repair kit on my shelf. Been there for many years. Never had cause to use it.

Nice orange caliper…

The back shaped to clear the hub?

I think I bought that kit to repair the MC on my Stella. I tore the seal being too gorilla handed with it and just replaced the whole thing. $80 and done.

This is a bit unnerving for me since i bought the same MMW brake master cylinder for my rusty VB1 project. There's a guy who is located in Greece that resleeves KTM hydro clutch master cylinders (Brembo and Magura) with a 10.5mm stainless steel sleeve. It ain't cheap at around 160 euros, but at least once rebuilt you would know it would last forever (just like the stock Grimeca MC). I wonder if he could sleeve other brands of MC's? Maybe option 1 would be to hard anodize the MMW MC while it's still brand new?

Interesting.
Perhaps there is some kind of burr from one of the two holes machined from the reservoir.
I'll have a look see today.
Thanks!

Question - what does one home a brake master with? Or does one not hone?

Usually hone with a small drill bit with 400-1500 grit strips taped and rolled around.

Spin the roll inside and let the flapping action do it's work.

Usually go in 200 grit steps in fineness.

Aiming for shiny/mirror finish.

Hit it with some emory paper wrapped around a socket

Thanks gents.

One follow up.
I would have thought that a cross hatch pattern was desirable - rather than shiny smooth?

a ball hone will take care of any sharp edges if the bore is smooth. most the MMW parts look to be made with a CNC Chisel on the outside, but I'd hope that the bore is reasonably good.

^^^

what mr. Owens said-- hit it with a ball hone. you can pick one up off flea bay for about $10

I have an ooollllddddd snap on three stone brake cylinder hone but the smallest it goes is about 1/2"

Patric/Greasy - saw these.
Just tied up with other shop stuff - so didn't get a chance to work on scoot yet.

I'm going to order a repair kit from Mercato if they have 'em - and grab a small hone - cause I'll have the time and its only about $15.

Thanks for the other comments as well - I thought it was normal that these things got stiff and nasty after 6 months...
Who knew.

Want to get this back to super smooth.
Might play with a handle design that is progressive as well - where it pushes on the piston - we'll see...

End of the weekend.
Scrolling through YouTube - as one does.
Line of "shorts" shows up - and I'm like: wait. thats me!

https://youtube.com/shorts/zTfHcCmRRZ0?feature=share

¯\_(ツ)_/¯

hahaha.
Hope y'all all have a good week.
Good motivation to get back at the scoot and get rolling again.

What can you say? Folks dig The Unicorn.

Mini Vespa celeb…

rock star

It's better (like everything else) when it's not displayed as a "short."

That is one cool ride.

Thanks!!

It's hard to say if I like tuning/restoring [sic] more.

After some great input from the crowd, I:
- realized my swing arm was worn
- realized my master cylinder had a burr
- realized I needed to get my scoot back on the road!!

Bought a master cylinder off Aliexpress for $25 or something. Maybe $14. IDR.
For those that don't know - the German companies are basically buying the same and rebranding.

Was curious.
Turns out - The quality is superb.

My chewed up master cylinder seals are still sealing.
Will replace with new and hone in future.
Temporarily hit with light sand paper and existing piston seals.
Smooth - for time being.
Thanks for heads up on Abby Normal west.

Got out and rode today.
72 and sunny.
Cali may be whack- as the kids say - but t shirt and jeans felt pretty damn good tday.

Appreciate all the help.
Few pics below documenting the situation.
- CM


Bit of modification required.

Seriously - the machining is excellent, and there was zero swarf. Why shouldn't I like RPM more then BGM at .15 the price?

Installed extra bleeder screw at low point and hung the caliper to fill (with syringe).

All assembled with new caliper in… orange. ¯\_(ツ)_/¯

Good for the sole

72 and sunny.
No crullers, but plenty of coffee and sun.

Oh man, the Orange Unicorn is badass, and clean! Very nice!

Man that thing is a statement.

Love it.

Cool machine and love the wood side stand.

You can do that sort of thing when you have a sidecar to store the block in.

He's showing off his wood.

If you had an 8" 4x4, you'd show it off, too.

Hahaha.

That block has been with me since I prototyped the leaning mechanism.
(I actually HAVE a side stand - but it just never ends up at the top of the project list).

It's versitile!
I can lean it in or out.
Turn it on its side or stand it tall - to change the angle.
You gotta see the beauty of it in action to fully appreciate.

Maybe I will whip up a fold down stand this year.
Tho it might be that block on a hinge.
🙂

Woof!

I came across this and I thought of you. I still have this fantasy about making a precise cut on a rotary pad using common tools. I also have a set of old T4 VW heads that the local machinist said he could not flycut. This looks promising, though slow. There are lots of fools on YouTube putting fly cutters on Harbor Freight drill presses. Looks like a great way to ruin your part and take out an eye.

So how are you liking the LED that you have installed?

Been working on converting my mill over to CNC.
I wasn't really sure why - until I cut my first part.
More on that soon, over on my shop thread.

I'm well outside LA now - much more rugged California coast and less gridded valley with stop lights.
The run to my shop on the scoot is a killer stress test for the motor, with the penultimate portion being a 65MPH, WOT, up hill run, for 4.3 miles, no letting off.

The motor now has about 4K miles (best guess) - and its running great.
The hill is such a stressor, I've used it to experiment a bit with the Smart Carb's rods (jetting).
But in my never ending commitment to providing entertainment - thought I would test something near and dear to my heart: temperature senders.

Now, I know what you're thinking - and it's true - you will never get these few minutes of your life back - but stick with me here for a sec - 'cause I have something you might find interesting.

First - some background:
The BGM was the first head I used that had a place to screw in a temp sensor.
When I ran it originally - I kept my under plug unit - 'cause that's what I had.
But at some point - feelin' fancy - I plonked down $20 of my hard earned money and installed the in-head version.
I was kinda shocked.
Damn thing started "over-heating" right away.
I knew I should have just left well enough alone!

But then it dawned on me - that perhaps reading in head was different.
So I did some quick testing - where I would have both an under plug and in head sender on the scoot - and would unplug one and plug in the other on the run.
This was no easy feat - as those plugs are designed to confound humans.
My results as best I could tell showed about a 50 degree difference.
Regular readers of this thread may recall - I postulated that the difference would grow as the temp went up.

Which brings us to today, the 4.3mile uphill run, and the purpose of this post.
For fun (ik, ik), I put the old under plug sensor in today, and did runs up the 4.3 miles first using the in-head feed, then swapping to the under plug feed.

Settings:
65MPH.
4th gear.
3/4-7/8 throttle.
Tool bag and 1 gallon of extra petrol in the sidecar for weight.
Sitting up straight (no tuck)
Leather coat
Air in the tires (though I have no idea how much).

Using the in head sender - temps climbed to a "whopping" 393° by the top of the hill.
When I reached the top, I unplugged the in-head and swapped to the under-plug - ran down the hill - U turned - and did it again.

This time - I noticed the temps were kinda slow to register.
But sure enough - they started to climb.
When I reached the top after ~4 minutes of just sitting on the throttle under load - temps hit... wait for it... 283°.
Not a typo.

Now some of you may be spitting and cussing at this point - and postulating all kinds of uncharitable thoughts about my honesty - but those are the numbers.
>100° difference.

Prologue:
There may be more to the story.
I made this run with the scooter's side cover (cowl) off the scoot.
And I suspect that the under plug is far more affected by external conditions than in head.
- does it touch a fin?
- is it in the path of the fan blown air?
- Etc.

Tomorrow - I'll make the exact same run again - with the cowl on the scoot.
Let's see if its a little warmer.
In the mean time - consider what a difference the readings for VMC/BMG/MMW heads that utilize screw in type senders vs under plug.

For me, it was more than 100°


The run. 4+ minutes at near WOT under load

The scoot - exposed to outside for both runs

The set up: both senders in place. Just plug/unplug between runs.

I only saw this after the event - about a month ago. No seize - no unhappiness.
Suspect I was just ranking on the throttle into the wind. (note: 433°...)
I need a Seventies with Sidecar sticker.