1978 VBC using a 2005 PX150e crankshaft
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Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Sun May 05, 2019 4:06 pm quote
So, I bought a used (under 2k) 2005 PX150e top end to plug into my 1978 VBC. All is well until the crankshaft is installed and is a bit too big (97.90 verses 97.2 and runs into the exhaust port.

Question: machine port lip or get a smaller crankshaft.

This one is a good one for the best and brightest Vespa aficionados.
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Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 559
Location: New Zealand
Sun May 05, 2019 5:19 pm quote
I have done this
Use your original crank with the Px 150 top end....which all fits together nice.
Cut a third port in the cases of the VBC.....not essential for running but will def give a boost in acceleration and some more top end...you can do it at home all by yourself

then

I used a standard hack saw and took 11mm off the leading face....11mm marked on the outside of the crank web NOT 11degrees...and this made a cut crank.......or buy the Mazz/Worb 5 one especially made for VBc

Its now VBC with the home cut crank...px150 top end.....and 22 tooth clutch..you need to add the 22 tooth clutch other wise it revs too much.

Eats up hills..maintains speed into wind..increased top end..solid 90kms all day
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Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 559
Location: New Zealand
Sun May 05, 2019 5:20 pm quote
and..
the POX 150 crank wont fit....even if you machine the lip the seals are different......use the original
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Mon May 06, 2019 4:11 am quote
Existing crankshaft
I would like to replace my existing crankshaft. What is recommended to match up with the PX150e?
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Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 559
Location: New Zealand
Mon May 06, 2019 5:46 pm quote
which cases?
the Px150 has a 15 mm wrist pin so will bolt directly on to a stock standard VBC crank.

a far better crank is the one by Mazz/worb 5 which has been cut and balanced esp for old scoots (fits in vbc or VBB) and is a straight fit with WAY better speed

The px 150 will save you money but NOT
give any increase in speed over a stock 150 it was born with

For more speed
Pinasco 2 port direct bolt on
Pinasco three port (will need third port cut)
Dr 177 (needs third port cut

soooooo cheap fix..new standard crank..done.......fastest scoot with more $$$ ....worb 5 crank with pinasco 177 three port

..and a sip road pipe on ALLL of them
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Tue May 07, 2019 3:40 am quote
Crankshaft on the way
I have this one on the way from my friends from San Diego.

crankmuz.jpg

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Tue May 07, 2019 7:04 pm quote
BoeingDriver wrote:
I have this one on the way from my friends from San Diego.
With a brass bushing?

Go with a needle bearing for your small end. Itís better and there is a reason why they went away from brass bushings. I have Pinasco 57mm cranks on the shelf if interested or you can buy from other US retailers.

Boy, what friends. 😂
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Sun May 12, 2019 6:31 pm quote
It's a MAZZUCHELLI
With roller pins.

Now I have a Piaggio crank that was pulled from a 2005 PX150e with under 2k miles for sale.
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Tue May 14, 2019 3:04 pm quote
Got the new MAZZUCHELLI..fits but does not rotate
So, this should work...Installed after bearing and seal installed using SIP crank install tool. What am I missing?

Molto Verboso
Joined: 26 Oct 2015
Posts: 1635

Tue May 14, 2019 4:28 pm quote
Re: It's a MAZZUCHELLI
BoeingDriver wrote:
With roller pins.

Now I have a Piaggio crank that was pulled from a 2005 PX150e with under 2k miles for sale.
Hi BD, I don't believe that a Vespa model 2005 PX150e even exists. I think the last time a PX150e was marketed in the US was in the early 80's. If you have a 2005, then it's just a PX150. It might help when you go to sell your crankshaft. That way people aren't thinking it might be a 35 year old crank.
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Tue May 14, 2019 5:49 pm quote
Thanks for that
That was the description that the guy from SW - San Diego gave me.

Now the real question...what am I doing wrong?
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Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 559
Location: New Zealand
Wed May 15, 2019 12:54 pm quote
no rotate?
Have you installed all other parts..or just the crank?...maybe clutch is binding???...bearing installed on an angle???...crank not all the way home....arse
Molto Verboso
One or two fun scoots....nothing too precious
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Location: UK (South East)
Wed May 15, 2019 1:12 pm quote
I'm surprised you were able to install with a SIP crank tool. It is designed to put pressure on the inner part of the bearing, which is behind the seal on an old style engine. Therefore it would have been pushing against the seal itself. With the old type of motor, you install the seal into the case, then both bearings onto the crank, then you seat the crank into the case, after heating it to 100-120 degrees C. No 'pulling' tool required.
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
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Wed May 15, 2019 1:17 pm quote
Some photos would help us, help you...
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Wed May 15, 2019 3:55 pm quote
Here you go
Thinking maybe un-square bearing...

1.jpg

2.jpg

4.jpg

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Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 559
Location: New Zealand
Wed May 15, 2019 4:21 pm quote
yep we have all done it
looks like the bearing was not seated square and is indeed on an angle.
Hmmmm.....prob best to remove the crank and see if you can tap tap tap tap the bearing down flush.(heat the cases)....but bearing races may already be bent...and it never really works due to the physics..when on an angle, the round crank web is more like an oval..and an oval wont go in a round hole
To be safe.chuck the bearing and replace it......other wise when you are next doing 90kms on the high way you will wish you had spent the $40 and half hour
..chalk it up to experience..there will be a few smiles from the experienced ones over this one.....
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Wed May 15, 2019 4:59 pm quote
You can see in the photo?
You can tell from the photo it is off?
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1560
Location: Veria, Greece
Wed May 15, 2019 7:22 pm quote
I donít think itís a bearing problem. Crank web seems bigger and looks like itís hitting the rotary pad...
Molto Verboso
Joined: 26 Oct 2015
Posts: 1635

Wed May 15, 2019 7:54 pm quote
SaFiS wrote:
I donít think itís a bearing problem. Crank web seems bigger and looks like itís hitting the rotary pad...
That's kinda my guess as well. Maybe if BD rotated the crank 180 degrees (so the cutout on the crank is positioned over the rotary pad), and tried reinstalling it again? If the crank doesn't turn after that, then it's pretty obvious to everyone here that the webs are too big.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1139
Location: UK (South East)
Wed May 15, 2019 9:49 pm quote
This is a bit confusing. Earlier in your thread, it was concluded that the PX150 crank you had acquired was wrong, so you bought a new Mazzuchelli one for an old style motor (as per your photo). However your installation photos show the later style clutch side seal and bearing arrangement, which is entirely possible on a very late (1978) VBC1M motor. Therefore, the PX150 crank would have been correct in the first place.

Have you installed an old style crank in a later style casing, or am I missing something? If so, you can ignore my previous post!
Molto Verboso
Joined: 26 Oct 2015
Posts: 1635

Wed May 15, 2019 11:11 pm quote
swa45 wrote:
This is a bit confusing. Earlier in your thread, it was concluded that the PX150 crank you had acquired was wrong, so you bought a new Mazzuchelli one for an old style motor (as per your photo). However your installation photos show the later style clutch side seal and bearing arrangement, which is entirely possible on a very late (1978) VBC1M motor. Therefore, the PX150 crank would have been correct in the first place.

Have you installed an old style crank in a later style casing, or am I missing something? If so, you can ignore my previous post!
Well, heck. Now I'm wondering if it's a 2005 VBC 150...
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Mon May 20, 2019 7:04 am quote
Engine numbers
Hello, engine numbers show a 1978. The pad is definitely the problem. I'm just wondering why the crankshaft webs do not fit the 1978 VBC motor as advertised. It should have been a standard case from 1978, unless there were factory differences for the VBC.

I'm trying not to machine down the port lip and my old crankshaft has worn threads on the flywheel side.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1139
Location: UK (South East)
Mon May 20, 2019 11:22 am quote
We can see from the photos that you have the later style clutch side oil seal on the inside of the bearing, like you would find on a modern PX. What type of bearing do you have on the flywheel side? The two piece roller? If it is, the PX150 crankshaft should have worked., although not sure why it was fouling on the exhaust port as you originally reported.

Which crankshaft is shown in your last photo?
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Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 559
Location: New Zealand
Mon May 20, 2019 1:58 pm quote
hmmm
you can see from the pic that the crank is not all the way home yet
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Honda elite
Joined: 19 Jun 2007
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Location: California
Tue May 21, 2019 8:54 am quote
You see the lubrication path at the transfer port but seal on wrong side of bearing or is that path closed and lubricated from gearbox on this model?
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Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 559
Location: New Zealand
Wed May 22, 2019 3:27 pm quote
agree
good spotting hibby....the seal is on the wrong side of the bearing...seal goes in the cases first.....bearing installed on crank before being pulled in together as one

which should give depth to the crank going deeper in and clearing the edge of the cases
good luck
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Thu May 23, 2019 5:37 am quote
Thank you all for your help..here is the plan so far
Fly side is indeed two piece roller. The seal sequence was as disassembled. I have noticed the other sequence in some Vespa manuals. What is correct for the 1978 era?

I will try the following:

Reset bearing to ensure square - then install crankshaft (the new one from Scooter West) turned 180 degrees.

Plan B: pull seal and bearing and install the proper sequence and parts. What is proper for 1978? I have seen the seal with an oil slot, is this the correct one? Part number would be super helpful.
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1560
Location: Veria, Greece
Thu May 23, 2019 6:05 am quote
Is it only me or does it smell like a bodged engine??
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Honda elite
Joined: 19 Jun 2007
Posts: 535
Location: California
Thu May 23, 2019 11:05 am quote
Do you have a photo of old crank and new crank? The crank you are installing appears to use the seal arrangement you currently have but my suspicion is you have the wrong crank, wrong seal and correct seal goes in first. The clutch side might look like this

446847DA-62D2-4576-8B26-64009E543EE5.jpeg

Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Thu May 23, 2019 11:47 am quote
Plot thickens..
As I laid out the crankshafts side by side and the plot thickens.

From the top:

My old crankshaft

The 2005 PX crankshaft

The Scooter West 1978 VBC crankshaft

So now, we can see the "new" Scooter West is not the same. Now, do I need to re-arrange the seals? Alos, I still need to figure out why the PX hits the port lip.

Need help from the VBC expert Gods on this one. If it is a Bodge, I would like to un-bodge it.

Engine number is: VBC1M 491254

Crankshaft line-up.jpg

Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1139
Location: UK (South East)
Thu May 23, 2019 9:39 pm quote
Your old crankshaft and the PX150 shaft both have the later 'P' style flywheel side taper. The webs are cut slightly differently, but the top two cranks are broadly the same. The new one from Scooterwest has the narrow flywheel side taper and is therefore meant for older style engines. The VBC went through a number of changes in the mid '70s as Piaggio was transitioning from old to new, and 1978 was pretty much the end of VBC production.

Assuming your clutch side retainer (circlip) is in the right place, the older style oil seal (with the lubrication cut-out) would go in first on an older engine. The bearing is then installed onto the crank, and the crank is then installed into the casing. Your picture shows a later style oil seal installed after the bearing, but a later style engine should have the circlip on the other side of the bearing (to hold it in place), with the seal then inserted after the circlip. Do you by any chance have a second circlip groove in the casing? Do you have a photo of the inside of the clutch side crankcasing, without the bearing and seal installed?

I think you should be using the PX150 crank, judging by the flywheel side setup that you have.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1139
Location: UK (South East)
Fri May 24, 2019 1:38 am quote
Taking a closer look, I am convinced that your clutch side case is the later 'P' style and that you have the correct seal type, installed correctly. That's because you do not have the brass bush which sits around the bearing and seal in an old style motor.

You've essentially got a very late VBC motor, right on the cusp of P125X production.
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Fri May 24, 2019 7:16 am quote
Yes two circlip slots
Here are the photos

circlip side 1.jpg

circlip side 2.jpg

Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1139
Location: UK (South East)
Fri May 24, 2019 8:00 am quote
Ok, so your installation of the bearing and oil seal was correct and you should be using the PX150 crank, not the old style narrow taper crank that you bought from Scooterwest. You have an engine casing that would later be used in the very first P series Vespas.

Sorry you had to take that oil seal out, as it's no doubt damaged now, but at least we know what type of motor you have. Once you have installed a new one, you'll need to pull the PX150 crank into the clutch side bearing using your SIP tool, but this time you'll need to pull it all the way in, checking for any resistance to ensure it's not fouling the crankcase/rotary pad. When you first insert the crank, make sure it's true and give it a little turn to help it through the oil seal. When using the puller, try to turn the crank a little as you pull it through the bearing, watching that the conrod does not get caught. You'll know when it's all the way through.
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Fri May 24, 2019 9:54 am quote
Still problem with hitting port pad.
So, should I grind down the pad a touch to provide clearance for PX crank?
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1139
Location: UK (South East)
Sat May 25, 2019 12:35 am quote
I doubt you'll be able to grind the rotary pad accurately enough that it still seals properly, unless you have some very precise machinery. The 2005 PX150 crank should be working for you as they have the same dimensions as the very late Super/VBC (sometimes referred to as Super 2). Here is a link to the genuine Piaggio replacement crank which covers your engine and any PX125/150, right up to the MY model, which the 2005 would be.

https://www.sip-scootershop.com/en/products/crankshaft+piaggio+for+vespa+_13315400

Seems like either your PX150 crank or the crankcase deviates from spec.
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Sat May 25, 2019 4:45 am quote
PX crankshaft is factory, so is case
Hmmm, the PX crankshaft is from a new factory scooter. The case has not been modified and has numbers that match lineage. It should fit, so I'll try one more time...ensuring square bearing etc.
Enthusiast
2008 LX 50 & 1978 150 Super
Joined: 29 Aug 2013
Posts: 54
Location: Connecticut
Mon May 27, 2019 4:17 pm quote
reinstalled PX crankshaft
yep, still hitting pad.

Waiting for my Chinese 3" grinding stone. Plan to set-up on drill press to grind the port lip. I'll try to attach photos.

Wish me luck.

Any advice from the experts before I cut into metal would be helpful.
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Honda elite
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Tue May 28, 2019 4:04 pm quote
what does Scooterwest say about the 97.90 vs. 97.20 variance?
Molto Verboso
Joined: 26 Oct 2015
Posts: 1635

Tue May 28, 2019 5:23 pm quote
BoeingDriver wrote:
Any advice from the experts before I cut into metal would be helpful.
Yeah, donít do it.

Iím not trying to be a smart aleck, but a grinding stone isnít going to be nearly accurate enough. I have a fair amount of experience with grinders, wheels, and stones, so Iíd urge you not to risk damaging your case. On the bright side, if you do mess up, it would be a good excuse to convert to a reed setup.

Hereís a pic of just some of my grinders... I got more sizes of them as well.

D96A91E6-120F-4E91-9013-9A89F132FD1C.jpeg

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