Modern Vespa

First off, it will stay 8 inch. No bolt in tens or Px conversions...8 inch

If you were commissioned to build the fastest 8 inch scoot what would you do?

Currently

VBC cases with third port cut
Pinasco 177 unmolestered
Dellorto 24/24
sip road pipe
22 tooth clutch banded
worb 5 crank with standard flywheel
Points

whats next in the need for speed.......aiming for solid 100km/hr

I have read "ode to speedy" ..Jennings..etc etc

Looking for info on port timings....crank mods..piston mods....gearing options...xmas tree swaps...packer plates


If you were commissioned to build the fastest 8 inch vespa what would you do?

meh. been there, done that, got 8" wheels banned from the old scooter racing league in the midwest in the process. what was it, like 17 years ago?

If i had to do it nowadays, and someone wanted to commission me to do it, the first question would be budget. because when people say they want the 'fastest', they usually do not have the pocketbook to match.

100 km/h isn't 'fastest'... that's not much more than well set up stock.

Are we talking pure speed? Fastest over a twisty course uphill or a salt lake? Is this a dream scooter where money's no object or are you looking for sensible suggestions?

I'd probably go for the Quattrini M1XL 172.

Yeah man, I'm in on this one.

You should already be close to 100km/hr with what you have. Where are you topping out now?

If you're already making enough power, DRT makes a 23T clutch cog that will bolt right on your Soop and give you a couple extra km/hr in 4th.

A Quatrinni would be nice, but if you don't want to drop a bunch of dough on a new top end, it may be possible to massage your Pinasco a bit and add a expansion pipe for some extra hp.

It would help to know your budget.

Cheers for reading.

Ohh, I also am looking forward to the results.. I think Speedy is a good benchmark, & if you get more speed, I'll just have to try faster, or ride better!
How bout a lap around Coromandel some day?

If I ever get my shit together, I'll be building my VBC motor, with ~20hp in mind. This target is based on SCK's claims that the BGM 177 delivers 15hp pretty much out of the box. Coupled with some fairly mainstream tuning and components, I think 20hp can be achieved quite easily. This won't produce the fastest 150 Super by a long shot, but it should comfortably manage > 100km/h over long distances.

A similarly spec'd PX150 motor is currently in my 150 Super, and it is wild, running with a jacked up cylinder (~1.3mm), 28mm PHBH, Scorpion pipe, Worb5 crank, and a SIP Sport Cosa clutch (21T). The gearbox is stock (PX200 gearing with 68T primary). Despite it being a great motor, I want the factory original VBC1T engine back in the scoot, but with similar power.

Do you have the later VBC motor with PX style crankshaft? If not, your narrow taper crank could be the weak point when going for power.

[Edit] Oops, VBC1M for the motor.

Is it time for a tuning sticky at the top of the forum? I seems like the tuning conversation always starts with the poster a bit in the dark. Seems like budget would be an absolute necessity to begin a conversation.

Bluecati...
If it was me (doing it all over again) I would concentrate on GEARING... I LOVE my setup, just about perfect, however I would (possibly) consider a longer primary.
As you have read, it took a LONG TIME to work out the current gearing
It did take a LONG TIME to "change" my riding/gearchange "style" to suit the box, but now I can extract the best out of what I have made... HILLS & TWISTIES are simply a dream... As soon as there is some form of REV-DROP, I simply change gears... It's always on the pipe, so in the powerband all the time!
Having said that, it's pretty crap around the city or "lights-to-lights", as needs time to get up to speed... But onc there... OHH WOW IT GOES.
I keep missing coming to visit you while I'm "home", this time it was only Coromandel & Bay of Islands... I can't remember where you are, but kinda remember it's at the south end of Bay of Plenty (my mum lives at The Mount, & besties have holiday places in Waihi Beach & Opito Bay.
swa45...
I defo will be impressed if you can extract any where 20hp from a small taper VBC motor... Can't wait.
It took a LOT of mods & many years of continual failures to extract 14.?hp from Speedy.

PureDrivenSnow...
A Sticky sounds great... May I request that if it happens can we PLEASE HAVE 2 of them... 150 & 200 motors separately, as they ar completely different beasts, & I get frustrated searching for mods, only to find is for a 200 motor.

NOTE: if anyone comes to Melbourne, I'm happy for you to "ride it like its stolen" up in the hills & should be able to get Ginchi to come along (& hopefully others) for a fun day (or a few hours) out... Just remember, Speed is a nasty piece of work to ride, & "aggressively" is the BEST WAY to make it easier, eg throttle stays ON, so yo have to twist it to turn it off... Simply letting go does nothing. I'm pretty sure even Ginchi is not a fan of riding it, actually, not many are!

PDS, I agree in principle, although the number of possible combinations is mind boggling. I also know from experience that budget goes out of the window eventually, or at least the initial budget constraints become blurred over time, as additional funds become available, and the desire to do a bit more becomes unbearable.

Is Vespa tuning an art or a science?

SEB, I take your point about the older 150 motors. To refine my statement, I might add that getting 20hp should be easy with kits, bits and Dremels, but maintaining reliability is another matter. A PX crank would be a good start, if anyone knows of a sensible way to do the conversion.

black magic.

SEB, Speedy sounds like a riot. If I'm ever that way, I'd love to have a go.

SWA, I think porting can look beautiful, so could be art but without the science it wouldn't look so hot.

One thing I always believe I like to highlight, is that the amount you spend doesn't necessarily make a fast scooter. How it's set up makes a fast scooter.

This one has been available for some time now.
https://www.sip-scootershop.com/en/products/racing+crankshaft+mazzucchelli+_45135100 It has the large taper and the correct setup on the clutch side, easy!
If I was going all out, I'd add a 110mm rod (and conversion bearing) to that.

The older cases - as long as it's a 3 pin rear brake setup - can be fine. With the right combination of bits you can fit an EFL box in there, SEB did it. I'm always gratified that SEB is a convert to the close-ratio gearbox. For a long time we tried to steer him in that direction. He only ever used to get into 4th when he was on holiday!

The other thing - if I was going all out for speed - is to fit a 200 bell crank and machine the case to take the reversed clutch seal/circlip. That would allow you to open up the inlet to the max.... with some welding to the outside of the transfers you could really open up that BGM. Or fit the Quattrini.

Thanks Ginchi, yes I bought one of those cranks, a used PX ignition and a complete (used) EFL gearbox last year, but it's all on the shelf. Note my earlier post and reference to "if I ever get my shit together"

I've seen some negative comments about these conversion cranks, but I don't think anyone can substantiate. I've also read about people manhandling an actual PX crank and the PX bearings and seals into an oldie case, but that's a bridge too far for me. Maybe those new DRT seal adapters and the conversion crank will be a good combo.

Sounds to me like Bluecati mostly wants to modify what he has, not necessarily buy a lot of new parts. That right Blue?

A mate has been using one a minimum of two years now and says it's been good. And he certainly doesn't baby his scooters. That might be right, going off his previous threads. But his question was on building the fastest, and the entry-level Pinasco 177 is simply not going to get him there.

The Pianasco 177 is a very good blank for Dremel training and the piston will handle a decent touring tune

Prepared to spend another 2k Nz on it. Im after an all round tourer..that must have solid 100km/hr to keep up on the motorway (free way)....and not drop back to 60km/hr on every hill. I have heaps of old PX engine parts and even more Super/small frame stuff.

so need advice on fettling the pinny 177 top end
will go for DRT 23 tooth..and possibly another xmas tree??

..and a better pipe

What are the port timings on your Pinasco Bluecati?

You have a Dremel and not afraid to use it?

If your engine is in good condition otherwise, you probably don't need to buy anything. Gearing is high enough already (22/67 VBC box 8 in wheel) from memory its near the same overall ratio as a PX125. Add a few more rpm to the cylinder and it should make 110 easy.

If you have to spend something then variable ignition will make a big difference.

I have one year to build a weapon for the NZ 1000 mile challenge 2019

It must be 8 inch(as point of difference among 70 scoots)

this thread is connected to other similar topic

Instead of using the 3port VBC...I also have a LML 150 in the shed with no top end which may be a better starting point for the 8 inch tune......gives me "lecky nish" and bigger fly taper right away.

Does anyone know if Super brakes /backing plate/hubs etc are compatible or if in deed it is possible at all to drop a ten inch LML 150 to 8 inch

Thinking of a BGM 177.top end.......but how do I drop all those revs and still have a useable 8 inch screamer/tractor?

..and which pipe given I am trying to drop revs but still get torque

ie How do I stop the scoot "running out of legs"

8 is the new ten

First of all if the LML case will upset your year of manufacture for the TT (it does in our Mille), you can fit a late gearbox in your VBC case. The difference is the shaft & bearings that carry the christmas tree, and that is solved fairly easily.
If you really want to thrash it then having that thick taper crank is going to give you an extra margin of safety... once again you can use the Mazzuchelli conversion crank if you need to stay with the early case and fit any one of the variable or stock ignition systems designed for the P series.

I'm 95% sure that the layout of the pins for the brake backplate etc is the same between early and late.

At the moment I can't find the exact number of teeth on the stock gears of the VBC so can't work out the overall ratio. But when you know them it's a simple matter to use this calculator http://gearingcalc.free.fr/ and feed in the numbers including the wheel size. The cheapest setup is probably what's in the LML at the moment, that is possibly (depending on year) a stock P200 set. Fit a T5 (or DRT) 4th gear to bring the gap between 3 & 4 closer, then choose a primary drive that puts your max torque at the bottom of your expected cruising revs.

The BGM is a good kit!

There will be plenty of options but I checked and on your 22/67 8 inch set up, you only need 7500 rpm for 115 km/h so not exactly high revving.

Easily possible. I would just port the Pinasco to give way more power. Same Worb 57 crank. Open the rotary inlet out. Keep the 24/24 carb. And a VBC conversion electronic flywheel (lighter) and a Kytronic 2016-2.

Doing the speed with the VBC engine is the cool part.

If so, how did you get on with meeting your objectives, and has the build been reliable? I'm asking because I need some reassurance that the puny/weaker input shaft in a VBC1M motor can take decent power on a long term basis. It's relatively common for high powered motors to crack the casing around where the input shaft passes through the case by the clutch cover. I'm wondering if this is more or less likely to occur with the thinner input shaft, which essentially leaves wider/thicker case material between it and the clutch housing.

My VBC1M uses the stock input shaft, together with the Christmas tree, shaft bearing and gearbox from a late PX125

Ya Bro Im still around. That project got shelved when i had an epiphany that i was "trying to make something what it was not" It occurred when I glanced over at a px150 in the shed and realised a super is a super and may as well keep it that way....ie three port,24.24,22tooth worb crank pinny 177,sip road.....which is a solid 90km on 8.....the old 80/20 rule...get those extra 10 kms was not worth it (philosophically too)

Currently working on a smallframe called a HP4 . Looks to be a precurser to the PX as it has electric everything and lots of bolt on plastic.

Thanks and no worries. I'll start another thread to see if anyone can confirm if a big increase in power/torque is going to be a problem for the old engine with the weedy little input shaft. On the up side, the fact that it uses the big (62x25x12) ball bearing on both sides of the crank probably means it is more robust than a P engine with it's little roller bearing on the flywheel side. That is with the narrow crank taper taken out of the equation.

Since the (inner) input shaft never seems to break - just the cases as you point out - then the thinner one should be fine. Or you could go to the type that has a step on the wheel side. 15mm for the bearing and 12 for the case, not sure if that's the type already in there. Guess the other thing you could do is enlarge the hole to take a later shaft.

With a hack saw at home I cut 11mm off the leading face of a standard VBC crank and polished it to hell .
It spun the standard xmas tree hard all over NZ during the first three Mille scooter challenges until Worby slid in for the remainder

That same cut crank is still screaming in another scoot with standard xmas tree. dr177 ,24/24,sip, road 22 clutch 8 inch..its such a winning formula,street and tour

Still not twisted any tapers on either crank even after extreme clutch tolerance tests via wheelies and burnouts,or the influence of piston/cylinder physical possibilities on that taper over multiple swap outs and lots of piaggio swarf on the floor.

A super is super

8 is the new 10

A vbc crank can handle the jandal

sounds like the angle of the jandel on your vbc crank is still good even if it's not a spring chicken any longer!