Modern Vespa

What numbers are 0.5mm base and the rest on the head to give 1.2mm squish?

I think this will be the best touring set up. And by this I mean able to roll on from 1500rpm in 4th, while having a degree of economy but still able to get to a reasonable top speed if needed.

I find it interesting that Malossi say the Sport is not suited for a 60mm crank. Or at least they say that the MHR comes in 57 and 60 versions.
I ran a Sport with 60 crank for a couple of years.

And I have one with 62mm Uncle Tom

Raising the barrel .5mm gives me:

T=179.1
E=123.1
BD=28

So timings raised a bit.

This leaves the piston 1 mm above the deck with a squish of .1mm, so a combo of spacers under the the head to add another 1.1mm.

Looks close to my numbers for my VMC 187. I have been happy with how it performs on the road. Plenty of low end grunt and I haven't revved it far enough out in 4th to have it fall off with the kind of riding I do.

I don't know why the Malossi Sport is only listed for a 57mm crank. I asked earlier in this thread and it seems to be inaccurate. Timings seem to be reasonably easy to set with spacers and shims.

I think the issue with 60mm stroke and the Malossi kits is the o-ring head design. If you put all the extra stroke under the cylinder, it will be too peaky. If you put some of the extra stroke under the head, you compromise the o-ring design. Maybe someone makes a head spacer that also uses an o-ring.

Assuming you meant That's a little low on timings. 124-125 TD is probably about right for an aggressive touring build with a box, just let the exhaust duration land where it will.

That should give you a little over 8,000 RPM's with a decent box exhaust before you get into serious overrun, but still come into the power down low.

Like it. Good for touring, not so good for racing. With a good set up it will still be plenty.

Im interested in how this works out for you. I still have time before my P project is done and looking forward to hearing your results.

Sounds just fine. I'm definitely not racing. I can bump up the cylinder a tad to hit 125 on the transfers.

Thanks!

Down is better than up. Try to keep the head gasket as a single. Squish is still ok at 1.5mm if that helps.

That's gonna be tricky. Does anybody make a 2mm head spacer?

Edit: Actually, more like 1.5mm. Scooter Mercato has it.

Yes, 2mm from SIP.

Could I use a steel shim? Will be a bit tedious to make, but I can do it.

I just ordered 3 different size ones from SIP. Cost $10 each and to be honest will probably function better than anything I could make in my garage. Mercato will also order anything you want from SIP and include it in their next order. Saves you the $30~ shipping fee from Germany.

Yeah…Patience. Won't be the last parts order for this engine.

I ordered a bunch before starting the build. Just not the thicker ones.

I suppose you could but I would rather have an aluminum spacer to match your aluminum head and cylinder. The steel wouldn't expand or contract the same. Might lead to a leak down the road? I don't have that experience to give you.

Statins apparently reduce the chance of a heart attack by about 30-35%.
But it turns out that's in relative terms.
In absolute terms, its more like about 1.3%
Meaning it drops your chances from like 3% to 2%

In plane English, that means that for every 77 people who take them, instead of about 26 people avoiding a hear event, instead about 1 person would.
Ouch.

Editors note: if you are taking your medical advice from this thread, you are likely already dead.

So why you ask am I mentioning that?
Well, somewhere around page 72 of my extravaganza, I mused about the issue of how to measure port timing, and how different the results could be due to measuring methods. (Vintage vespa with sidecar (**Now In Technicolor ! **) (Page 72) )

Reader's Digest:
- Depending on the method - you will get differing results.
- The difference is highly significant (like 5-10+ points of timing).
- The best thing to do is to settle on a method you can repeatedly get the same number from each time you perform it
- Consider your number "relative", meaning, if you don't like the way it rides, take it up or down and use the same method of measure to achieve your adjusted target.

See what I did there?

Anyhoo - the unsaid part is, it turns out that just being able to measure and get the same damn number is it's own challenge.
And
One mans 180 is another man's 187 (on the same cylinder).

In the end, I felt the calipers were the best for me. I began using my little electronic microscope because I realized that what alters the measurement I was getting from one effort to the next, was how deeply the tip of the caliper poked into the transfer or exhaust port.
Once I had a consistent method, I stuck with it and decided if I liked it when I rode.

Below are a few images from that post.
This was the difference from about 5 + degrees of timing if I recall.

In hindsight - If I had been on my game - I would have machined down a spacer block to fit the throat of the calipers so that they sat both parallel to the cylinder wall, and at a depth that would repeat.

Hope its at least a little helpful.
Cary on.
-CM

Preach it, brother. Isn't that the truth? It's all relative. Proof is in the pudding when you actually start test driving. These engines are way more complicated than the engines I work on for a living. Just installed one that cost $109,000. I get nervous working on these 2T engines sometimes.

Yes, definitely helpful and pretty
much the method I use. I shine a flashlight in there so I can see the tip of the caliper. Measuring a port map definitely gives lower numbers. I tried it because it seemed less fiddly.

When I lowered the timings on my 187 to deal with a heat issue, I didn't notice any difference in how it went down the road. I don't have enough experience to notice subtle differences in performance. The heat issue was most likely the leaking clutch side seal. Maybe lowering the timings and opening up the reed helped…

The reason I don't open up, match or otherwise massage ports is because I am unlikely to notice the difference and might end up doing more harm than good at this point. So I'm happy to pick the low hanging fruit.

I'm still too much of a chicken shit to push even my stock 200 to its limits. I still get that jump scare feeling when I come up too fast on a turn. Way better than when I started though. Speeds that were once terrifying are now relaxed. I think my engine building skills are improving too.

Makes sense.
On my current build, whose description I think it would be fair to say was "experimental", I actually left the cylinder completely untouched.

My focus was on durability, and even though it looked like a blind man with a sanding wheel had put the chamfers on at the factory, I didn't want to risk creating areas for chipping

I've got to be four or 5000 miles in on that motor, and nary a scratch on the cylinder wall. So my thinking is not so different.

I was impressed with the ruggedness of the stock 200. Piston and cylinder look very unrefined. Reassembled the oil pump wrong and ran some miles with NO oil. Rings looked a little chewed, scoring on the cylinder walls, but ran fine when I got the oil pump working again.

The stock P200 motor is the AK-47 of internal combustion engines.

Sloppy tolerances and extremely conservative capability, but pretty much unkillable as a result.

I'd say that's accurate, and true of most stock Vespa engines. As tempting as it is to tune it, gotta have one to ride when the tuned engine is driving you crazy and you're on your 16th page of jetting.

Can't agree more. Before I had to rebuild my 'stock from factory' p200, it kept soft seizing and I couldn't understand why. Took me a few days of riding it like that to even realize that's what exactly was happening. Turns out i rode it for like 3 full days with no oil getting to the carb and it rode honestly pretty fine for the most part. I made it home every single day anyway.

Got my 1.5 mm head gasket from Mercato. Squish was a little in the big side at 1.75mm, which is fine as I have .5mm of shims under the barrel to play with. A .2mm under the barrel would give me a squish of 1.45mm, which seems ok for a touring engine.

Gonna measure my transfers again, run the numbers, check with degree wheel and recheck squish when it's back together and torqued. Oh, and mark TDC and timings on the super cool case with degree marks already cast into it.

Next step will be a pressure test.

I'm considering replacing the flywheel for no special reason other than that the LML one I have is old. Maybe I will wait to see if/when I upgrade to a Vape ignition.

Measured the transfers again and this is what I got with a .2 mm spacer under the barrel, 1.5 mm under the head:

PBT=-1.3mm
T=124.1
E=179.5
BD=27.7
Squish~1.45mm

Those numbers look rock solid for a touring build with a sport box (Polini/SR3/BBT/etc)

FMP has been posting a lot on facebook arguing/demonstrating that most of us actually have port timings set too high for modern kits, with the VMC244 as his specific example.

Unless the goal is to get peak HP sacrificing rideability, I tend to agree with him. Watch the RPM's where you spend most of your time and it's not 9K+ (at least not on largeframes)

https://www.facebook.com/share/p/18oMYgFUbV/
https://www.facebook.com/share/p/188oCpz6t7/

I've been following his videos and agree. High timings aren't much fun if you are not spending time enjoying those high rpm's. If you are a connoisseur of riding at 8k+…by all means go for it.

I don't think I've seen much past 7k in 4th on my Stella. The fun for me in the back road touring rides I do is having lots of torque.

There is a scooter club in Vermont that does some ambitious rides on some of the busier state highways (not interstate). A lot of them ride modern Vespas. I would like to keep up.

Yeah, something I learned with the Smallstate is that when it's up in that peak power band, the throttle is so twitchy that it's exhausting to ride after a while. Great for racing, but not so much for touring.

All of my other bikes (Sprint, GL, even the VBB on 8"s) are set up (or on the way to getting set up...GL, I'm lookin' at you...) to be able to cruise at 65-70 MPH without me needing to watch the CHT and/or EGT like a hawk.

Getting those sorts of sustained speeds is easily do-able motor-wise with your current build. Just confirm that the RPM's for 70 MPH (or whatever speed(s) you expect to cruise at), seem reasonable for the rev range and expected power output.

The seat, suspension, wheels, tire balance, etc., combined with practice riding at speed are going to be the real determinant of whether or not you're comfortable on the highway, though.

Riding the Stella fast was night and day after changing shocks and bushings. Should be as stable and planted as the 200 once I put the new tires on. 200 has all of the above and 60 feels the same as 50.

Nothing exciting going on other than squish coming out around 1.4-ish mm as expected, which always feels like a small victory when the actual thing agrees with what's on paper.

Fought with the piston rings a little as I put one upside down even though I "knew" how they go. Really obvious when they're wrong. It's sorted now.

What exhaust are you going to run? I can't recall and am too lazy to go look.

SIP Road 3.1 Dellorto PHBH 30, VMC clutch and short 4th.

The 3.1 has a bung for an O2 sensor, so I may borrow my AFR gauge from the bus for jetting…though I'm not sure how much it will help. Getting bus plugs out to read them is a bitch out on the road.

😊

Those timings are probably too high for that box.

Don't worry about the exhaust, but get the transfers down to 124 or so. You're just not revving that high.

(and if you're on board with FMP's latest thinking, even 124 might be too high, at least for the latest round of kits, e.g. the VMC 213 &244)

This is where I am now:

I like those a lot more

Interesting...

I did my Q252 straight out of the box with timings not so different - 176-126. Then I had my little timing accident and ended up having to remove a lot of material. Ended up at 188-126. Still Polini box and everything pretty much the same. Now I have noticeably more power right through the rev range.

FMP has plenty of insight and experience but not always correct I think. I haven't seen the videos on FB because he unfriended me for saying he didn't like Pinasco.

There is always more than one way to do things, especially with tuning…for any kind of engine. Many different expectations and measures of what makes a successful tuned build. I'm glad I started with getting a stock engine build sorted out. I think you need to experience success with the factory item as a point of reference. After that, tuning should be within the limits of your skill set and understanding of the changes you are making.

A bit sad to be dropping the VMC 187 engine and poaching parts from it for the Malossi build.

Noticed the damaged rim for the first time. Pretty sure it happened when I hit a culvert repair that I didn't see coming this past summer.

Glad you caught that rim damage now!