Modern Vespa

the gasket could be a dual use gasket. 1st in the oem configuation where the holes stay in place, 2nd in the malossi config where you need to punch out the spots for holes.

Did someone say sue? I think I can be of assistance here. . .

The mention of gʻlt and the Advokat chimes in.

The cylinder kit has a 74mm bore, the stock is 72mm. IIRC the head gasket only comes with the malossi cylinder and I don't think the cylinder is intended for use with a stock head. If you are just using the Malossi head with the stock cylinder you use the stock gasket.

From this I'd say that the gasket was made for that combination, but then I remembered that the 210 kit for the GT is also 74mm bore and can be run with the stock head. No idea if it's the same gasket or not.

I'd assume this as well, though (IIRC) some of the gaskets that come with the Malossi cylinder are actually Piaggio products. Can't remember if the head gasket was or not.

Something else I noticed this evening: the lower right-hand stud is coked, while all the other studs are completely clean. Perhaps that's where the compression leak was happening?

Jess needs the truck.
Thanks for the write up

Now I don't feel bad that i haven't torn my CBR motor apart yet

Slacker!

looks pretty much like Jess' without the bloat...and this is a Ms. scooter...
not as obese as i thought...
gasket adhesive...anyone...bueller?

(re oriented gasket)

Progress has slowed of late, but I moved forward a bit today. I took a stock 250 cylinder to Gary (the piston was already machined, but that's a whole 'nother story) to deck the cylinder by 0.5mm, as per the Malossi instructions.

As usual, there are pitchers!

And because Patrick always wants data -- in this case, to calculate the final compression ratio -- I spent a bit of time CC'ing the piston with a graduated pipette and some cheap vodka.

The bowl in the piston is right about 12cc.

BTW, my machinist Gary is now set up to do the necessary machining on stock 250 and 300 top ends, specifically for the Malossi 4V head. He has built the fixtures to do it, has done four or five of them so far, and is very familiar with the process and the specific measurements. In other words, you do not need to explain what you want done. Gary knows. He's now as close to an expert as there is on this topic.

The price for machining the cylinder and piston (as a pair) is $150. Contact me via PM if you're interested and I'll connect you to Gary.

That's not too bad, all things considered!

Ye flippin' gods, if you are going to drink cheap vodka, at least get the real stuff: Monopolowa

Available from the same place as Paint Stripper of the Gods...

This thread is very very very very useful... just thought i would add that to the discussion!

For the cheap vodka recommendations?

Who said anything about drinking it?

Well, the bottle is half empty

See I would say half full.

For the record I advised him to use whisky for this measurement and to drink the experiment when done. Whisky would also have provided more contrast and therefore more accurate results.

And whiskey has a slightly lower evaporation rate than vodka contributing even more to accuracy.

I just made that up

depends on the aging.

I suppose I could have added food coloring.

Moving slowly along. The Malossi V4 head has built up quite a bit of cruft, so I'm going to tear down the head, scrape the buildup off the valves, and then re-lap the valves to get a nice clean seal.

Here are the valves coming out:

I've just spent the evening at Gary's house, walking through the process of cutting another 250 piston. We had originally intended to use a brand-new, untouched stock 250 piston, and he had cut it some time back for this purpose. Unfortunately, we discovered that the cylinder I was using (that he recently decked) was a type M cylinder, and the new piston was a type N. So we went back to the piston that came with the type M cylinder (also type M) and did the cutting process again on that one.

Here are the photos of the cutting in process. The cut piston is utterly beautiful, with each cut edge hand-beveled to eliminate any sharp spots.

Beautiful indeed.

I have to admit having a bit of a fetish for well machined metal.

My colleagues in our aerostructures department have caught me fondling machined aluminum and steel fittings and parts sitting on their desks awaiting inspection.

I just find them, well, beautiful.

And when I see nicely swirled finished on a machined part that feels smooth to the touch (see below)... well [~swoon~].

http://www.circuitousroot.com/artifice/machine-shop/surface-finishing/engine-turning-vs-spotting/index.html


feast for your your eyes, Trepp!

Um... I think I need a moment.

And do you know this one?

http://www.warthercutlery.com/

Strange to say, but the effect on cutlery doesn't do it for me. I do have a thing for fine cutlery, mind you. But I because there are so many more important considerations with knives than looks, I tend to be suspicious of knives whose selling point is primarily looks.

For my kitchen, I ended up going with a very nice set of high carbon knives from Sabatier. I like the balance and build of the French knives over the two or three excellent German knife sets I was considering. And the high carbon steel, takes an edge like crazy (but needs to be resharpened frequently). Also, even if you dry and oil it aft each use, the blade tends to get dark with age. But I like that look.

Well, with a little time, a cork, some machine oil, and some iron filings, you could have some machine turned Sabatiers ... the best of both worlds. You would also develop enormous forearms. Your throttle hand would never tire. (Scooter related)

http://www.kitchen-knife.jp/

Drool away!

I have had a set of his knives for about 8 years.

The secret is Camellia oil, food grade. Brightens the blade when you oil it. Keeps food from sticking to it as well.

Waterstones will also put a better edge on high carbon steel, better than oil stones by far. Synthetic ones are easy to get hold of, natural ones cost a fortune.

A Matagi-Shotou is the latest of his knives in my collection.
http://www.kitchen-knife.jp/special/echigo.htm

Not really a kitchen knife, but a hunting/fishing knife. Made from wrought iron from old anchors, the hammering effect is hard to describe. Being exposed to the salt water for decades creates some large iron crystals. That structure shows up in the naturally blackened portion of the blade. Mesmerizing, if not fascinating to look at in the sun.

That is beautiful enough to be art work. I admire people with this talent. John, Kruella_DV, made some spare conical nuts when I had lost one on my GIVI windscreen, it's the same thing, more than machined metal, work of art.

Terrific that you're showing us this. I'm commenting so that I can find this again easily; I thought I might've missed the completion of this project.

cheers

You can also mark it as a favorite with the "star" button up in the upper right corner of the topic.

At some point in the not too distant future I'm going to have to have, at very least, the rings and head gasket replaced. My scoot is burning oil more than it used to (although not at an alarming rate), and I have a little oil dribble on the outside of the casing that needs to be wiped off ever couple of weeks.

So I'm toying with the idea of ordering the Malossi 4V head... But need to know what I'm getting myself into.

Does the kit not come with an appropriately machined piston? Is there other work that has to be done to fit the new head to the existing engine?

Is there a potential downside to kitting the engine?

Is the Malossi 4V head something I could fit into a suitcase (shipping to Israel would probably double the price)?

Could be as simple as needing a new gasket (either the base or the head, I don't know -- where's the oil coming from?) If you buy the Malossi head and the cylinder kit, then you end up with all the parts you need, and a CC boost as well. This is the configuration I originally built on my CB bike, but am now in the process of going back to the stock cylinder / piston. I think the Malossi cylinder kit is what's losing oil, but I am honestly not 100% sure.

If you don't use the Malossi cylinder kit, then you have to machine the stock piston and you have to shave 0.5mm off the top of the stock cylinder. This is what Gary did for me in the posts above. Yes. Kitting the engine must always come with acceptance that it could all go pear shaped at any moment, and eat your entire engine in the process. It probably won't, but you should accept that it is a possibility from the outset and be at peace with that fact. Also, if you machine the stock piston and cylinder, you can't really go back unless you get a new stock piston and cylinder. The head itself is, in my opinion, very high quality. Yes. Definitely. Even with the cylinder kit along side it. Each box is maybe 4 x 6 x 8 inches.

Thanks Jess. From what I can see, it looks like the oil is seeping from somewhere on the head gasket. But it is the tiniest of dribbles. The real oil consumption is almost certainly just worn rings. After 100,000km that's bound to happen.

I'm not sure if I'll end up doing this. My wife and I are making our wish lists of stuff to buy while in the US this summer. If history is any indicator, we'll sit down with our respective lists a couple of weeks before the trip and try to prioritize (meaning she'll cross stuff off my list as impractical, too expensive or both).

Truth be told, I don't feel the absolute need for more power. It's more like a want. I've had a 750 MC in my youth and know that having reserve power is a terrible temptation. .

If I manage to slip this past my wife (and my own common sense) I'll almost certainly buy all the necessary parts. I don't want to start machining things over here.

Thanks again for the detailed response.

A bit more on the elephant in the middle of my shop CB bike. I spent some time this afternoon lapping the valves on the Malossi V4 head.

I'm starting to reassemble the head. So far, I've removed the old valve guide seals and installed new ones. Now it's on to the valves.

I'm spraying each part with an alcohol-based cleaner, washing each part, drying each part, and then installing it. Kinda slow going. I've got the exhaust valves in so far, will do the intake valves tomorrow.