Modern Vespa

Finally, started working on my new engine build. I bought (dirt cheap) a set of cases a few months back, with a damaged rotary (someone decided to dremel the sealing surface). I have already gathered the needed parts and "beefed up" all the necessary surfaces. I've also made a reinforcement plate for inside the gearbox (seen it from a British bloke) which is going to be welded after I finish porting, in case I need some more touch ups. Tomorrow, I'll probably take out the cylinder from my current engine and start matching the ports. This time, the cylinder will be slightly raised, so as to change my port timings...

More updates to come...

I'm definitely interested in hearing more about that reinforcement plate! Do you know what series aluminum alloy it is? What filler rod are you planning to use to weld it with? How thick is the plate? Are you going to be giving away any templates of it next Christmas as "stocking stuffers"? Is there still room to easily fit the rear inner axle seal (for the PX EFL cases)?

I always love reading about your projects! Thanks for sharing.

I saw the plate on a 40HP build. The guy that built it, said he's done a lot of them and none of them ever cracked on the primary's axle seating. Plate is 5mm thick. Grade 6061-T6. For a filler rod, I think my welder uses 4043 which is of course suitable. I'll do a template scan of the plate and upload it here. My cases are EFL but with the outside seal. If you widen the axle hole, it'll probably allow the seal tool to pass through...

There were two EFL axles, at least in the Greek market. 1st generation still had the seal outside (after the bearing), like the old P gearbox and 2nd generation had the seal inside, before the bearing. It was common on the PX200E Arcobaleno, with E-Start, non auto lube. These are the cases I have...

That, my friend, is news to me. I'd always assumed all post-1984 bikes had come with the upgrade. How long did the first gen arcobaleno series last? Is it not just a matter of the few first engines being passed over from the mk1 series?

On the reinforced gearbox front, a few guys have been developing these plates in France as well:

I believe Piaggio had a lot of left over cases, so they mixed and matched. My EFL gearbox I currently have on my old P cases, was taken from an Arcobaleno engine, with E-Start and non auto lube. The only difference is at the axle, which isn't machined for the inside seal. I'll post some photos when I'll split the old engine...

Pictures are courtesy from Scootering magazine from back in January 2012...

And a closer up pic of the two different EFL shafts.

You always do some exciting stuff Safis! Really like the stiffener plate! Is it a place that fails often? Or is this only to beef up the primary area next to the clutch opening?

A friend of mine who built up a case for a KDX200 cylinder and did plenty of bracing used a similar sytem to stiffen the clutch side.

On powerful engines, or when the gearbox explodes

Mike, as Frank N. Stein already showed in the photos, the most sensitive section is the primary's axle seating. If they crack there, then it spirals down pretty quick, to full failure. The British bloke that posted the photo with the plate, said he's built like 10 engines ranging from 30 to 40 HP and never had one fail (he has a shop). As he explained it, when the engine is putting down too much power, the gears tend to push back each other, resulting on too much stress on the cases. With the plate welded in place, they don't flex that much. Better safe than sorry, I always say. I really liked your friend's build and I'll see if I can have the top of the axle seating welded like he did (I hope it clears the BGM clutch). I've started working on the porting / filing down, so I'll keep the thread updated...

And here's the link to the plate's template. It's an A4 scan so it should be scaled to 1:1...

https://www.dropbox.com/s/dbeu67pwkksh9xo/Gearbox%20Plate.pdf?dl=0

Cheers for that... looks nasty!

I see what you mean now and how it helps.
What's the diameter of the hole in the middle? Wouldn't mind double-checking the scale.

Following this with interest The welded plate is the business. Makes the casing almost wheelie proof.

Looking forward to see what 40bhp porting pulls a 24 tooth

Mike, I used a 40mm hole saw and after cleaning with the air grinder, it came close to 41mm. Jack, I am not aiming that high. Anything close to 30 will be fine. The 24 will be mostly used on long trips. I'm already running the T5 4th...

The T5 cog is a 2% reduction and the 24 tooth is a 4% increase.

When embarking on a porting project it is a good idea to have a plan for the max power rpm and where the torque should be.

As stock gearing is already too high, it will take a touring type tune to pull this gearing. A touring type tune might get you 25bhp at best. 40bhp is not so hard to find but due to the fact that it is 40bhp, the torque will start too late to pull that gearing. Just saying.

If you have a 22 or 23 tooth handy they could easily be be selected later, if you do end up with too much power

Last edited by Jack221 on Fri Feb 23, 2018 7:37 am; edited 1 time in total

Thanks for the info Jack. I am now running the Malossi Sport (2016) which I'll raise 1mm and use a 0,5mm at the head and a PWK 30 with the MRP Reed. I hope the carb will be enough to feed the engine. Will also use a Mikuni pump along with a long range tank (GSF) I'm going to build...

Will keep you guys updated...

I just swapped in a 24T clutch in my PX215 (it already had a T5 4th). I haven't had a chance to ride it yet. I''ll be interested to see how well it pulls in headwinds and up the hills. If it doesn't work out...then back to the 23T!

What primary are you guys using?

Safis I am running almost the same, except for the 0.25 base gasket and the rest at the head. Did have a 30mm OKO and swapped for a Keihin PE (round slide) 28 with MMW1 (less direct) reed block that Vader gave me. What pipe are you going to use on that?

Last edited by Ginch on Thu Feb 22, 2018 8:00 pm; edited 1 time in total

Primary is the standard 23/65. So far I was running an MMW longstroke head. I bought the SIP head to replace the MMW and raising the cylinder will give me a better exhaust duration. If I could find 0.75mm packers, I would have split the "distance". Pipe wise, Cobra 220. Maybe later, I'll go again for a Box type, again from Marco. The SIP XL I had, had it's diaphragm fall apart and I managed to get a refund from SIP (only 2k Kms on it)...

So, basic porting is done. Ports need polishing. Next is the intake. MRP's stencil is in place. I tried to split the old engine, but the f@cking flywheel, won't budge. Have left it tensioned for the night. I hope it pops by morning. If not, I'll apply some heat. Thankfully I have a second COSA II flywheel. In case I'll need that, I'll have to lighten it first...

Few photos...





























Updates to come...

Love those ports, nice work.

Looking really great. What crank is going in?

The Pinasco flowed, I already have. Pinasco's C.S. has confirmed it's compatibility with a reed setup. They use the same cranks on their slave cases...

I've been running flowed cranks with my reed setup's ever since Rob Hodge pointed me toward one for my first souped up LML rebuild and have been pleased with the results every time.

You have a link to it, so I can see exactly?

This is the one I have...

https://sip-scootershop.com/en/products/long+stroke+crankshaft+pinasco+_45028000

I thought it was going to be a rotary crank. Really nice crank but not ideal for this set up.

This is the kind of thing it should have.
https://www.sip-scootershop.com/en/products/bellshaped+crankshaft+mazzu_45041000

When changing to reed a bell crank will give the best results even for just a tourer.

I am very sure the Pinasco could be more use in something else.

Will see about the Pinasco. To tell you the truth, I've done a lot of research and I got even more confused. Lots of people say a full circle is the number one option, others the bell shaped ones. From what I understand, both types have a different effect in the pressure that builds up in the cases and the flow of the charge. If I could find a lip-type longstroke, which combines best of both, I would go for one (they are out of stock for months). Maybe later...

All depends what is being built. There is way more to this but to try to simplify it for a reed engine, full circle works well for smaller cc when tuned for high rpm (like 10,000 plus). Bell works well for bigger cc and lower rpm power.

Like you say is all about flow and pressure but as yours will be a 221 with a small crankcase and higher gearing (even 22/65 is high), then a bell crank is what I think would go the best.

I'm afraid I'll be going for a new crank. The flywheel still won't budge. We cut the rivets and now I am left with a stuck center and a new developed problem. When turning the crank, it tightens on one specific point. I'm afraid it maybe got warped. So, bell or lip type?? I am already way over budget, so if I can dodge the bullet for now and the Pinasco comes out unharmed I'll stay for now with it...

Jack, is this the same as in the link you posted??

http://www.scooter-center.com/en/product/7673690/

Yes it's the same one... it's what I'm running in mine and I'm very happy with it. Apparently it's made from the same steel as their full circle cranks which is a stronger grade. Excellent value I think when you compare it to say, the S&S bell crank.

There's a ton of stuff you can read about low crankcase pressure vs high crankcase pressure, but the fact is if you use a full circle crank on a Vespa with the normal position intake, then the crank is going to be in the way. Even just adding the reed block increases crancase volume significantly. There's other options though... this is impressive and would be even less in the way than the bell. I'm sure you've seen this Jack - https://www.scooterotica.org/forum/viewtopic.php?f=53&t=33118

Gave in and ordered the crank along with some bits and pieces from SC. I have the tools to align and weigh the Pinasco, but I somehow lost trust in it. But it will be of use, on the next engine build I am planning, for a project I have in mind...

This crank is most suited to what you are building. For the clearance from the reed block and the increased crankcase volume. Not too light a flywheel though, something like 1.8kg.

Still not got that flywheel off the Pinasco crank? Tried heating it with a hot air gun?

Center still stuck. Rest of flywheel is out, after cuttings and drilling the rivets. Basically is totaled. We even used a torch but it didn't budge. I have a spare one but I'll have to lighten it and have it balanced again. The one I had was 1850 g.

That sucks. Any idea how that happens? I've seen it before on this forum but wondered what happened.

John, I really don't know why it got stuck like that. Last time I had it out, I lapped it on the crank, because I could take it out without using a puller. Maybe I overdid it, I really don't know. Anyways, I came home from work and my father had already taken out the center, by cutting and grinding it. I split the cases and started cleaning up the parts that are going in the new build. BGM's cruciform is crappy. Only 2k Kms on it and I really don't like how it looks. Ordered an original one. I also opened up and polished the side windows on the piston. The Pinasco crank, got measured and it turns out "true". The problem, was due to the tension created by the puller, when I was trying to get the flywheel out. Anyways, it will go on the next project. Waiting for the bell crank and few bits and pieces from Scooter Center. I'll have them in a week. In the weekend, I'll drop the engine and make some more preparations...

Few photos...





















@Frank N. Stein: My EFL MKI axle...

Well i appreciate the picture of the wear pattern on the cruciform. How many miles are on it (or better yet, how many hard miles are on it)? I'm guessing that the DRT, Crimaz, BGM,ect shift crosses are made of the same material?

The cruciform had about 2k Kms on it. I'd say, mixed use. It's supposed to be better than the original. BGM says it's made from high quality 15CrMo5 (SCM415) chrome molybdenum steel. Crimaz says cruciforms are produced using a special steel alloy (16NCD12), vacuum formed and tempered. The surface has a certified hardness of HRC 58-60. Serie Pro ones say they are made by MJ9+. I really don't know if they justify their money...

I'm using a cruciform given to me by a mate... his mate had been mucking around with cryogenically treating metal so he asked him to do a few cruciforms as an experiment. It's been in a while now and seems fine but won't really know until I pull it out... hope that's along time off.

Glad the crank came out unscathed! Still looks shiny.