Vintage vespa with sidecar
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Thu Mar 25, 2021 7:34 am quote

(BFA - stands for Big Fucking Ass motor.)
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VBA
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Thu Mar 25, 2021 12:35 pm quote
I've missed a few days of chat, so I will be slightly all over the place.

I agree with Swiss about being concerned about using the crank in its current form. I wouldn't be surprised if there is rubbing on your cases near the crank.

Socal: LOL at meteorite, looks like you found the source.

CM22: A thought I had over the past few days. The 2 crank halves got rotated independently from each other, possible due to copper bearing sleeve being off. This could also possible happen in higher stress situations. Another reason to check runout of crank while in cases if it is not too late.

Wait, are you on VBB cases? In my head I had you on a P125/150 case.

Whole Hog
For "whole hog", why not go to a Malossi Vone (P150 or P200) cases at that point? The VRone comes with the reed stuff I believe. Both come with crank bearings/seals, and gaskets (helps offset some of the cost). Extensive machine work for your current cases (to clearance P200 width + fixing brass insert) seems like it would add up quick. Then add all the welding and decking.

When I went down my crankshaft rabbit hole, I remember seeing a few things but I didn't verify accuracy. To use a P200 crank in a P150 you shave that extra lip off the P200 crank or carve room for the lip in your cases (machine shop), is this what the conundrum you are working through with using a P200 crank in 150 cases?

Full circle rotary valve crank:
I saw this when I was looking at cranks, but for P150 is was still just a 105mm rod. I couldn't figure out the point of it.

For the P200 version CM22 linked (45021710), it has a 127mm rod, but a 60mm stroke (vs 110mm on a 60mm stroke). QUATTRINI has a similar crank and states in their descriptions that the longer rod length "increases capacity" (WTF does that mean). Did they move the rod bearing inboard to keep a 60mm stroke on such a long rod?

For the deep thinkers: For cylinder timing, it is always discussed as ED, TD, BD, and ID (Intake duration). How does intake opening (ie wider crank web allowing for intake grinding perpendicular to crank axis) or a larger diameter P200 exhaust on a 150 motor (ignore stub side difference for this argument) get accounted for in the maths? An engine is air pump, so it helps somehow. Does opening the intake at the rotary sealing area (as described above) really help if you have a choke point in the system (ie hole on top of case is only 24/24 sized but you are running a 30mm carb)?
Ossessionato
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Thu Mar 25, 2021 2:13 pm quote
Captcha wrote:
Both come with crank bearings/seals, and gaskets (helps offset some of the cost).
Small correction. Only the VR-One cases (reed version) come with bearings & seals. The V-One don't...
bodgemaster
63 GL, 76 Super (x 2), 74 Primavera (x 2), 06 Fly 150
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Thu Mar 25, 2021 3:06 pm quote
Quote:
For the deep thinkers: For cylinder timing, it is always discussed as ED, TD, BD, and ID (Intake duration). How does intake opening (ie wider crank web allowing for intake grinding perpendicular to crank axis) or a larger diameter P200 exhaust on a 150 motor (ignore stub side difference for this argument) get accounted for in the maths? An engine is air pump, so it helps somehow. Does opening the intake at the rotary sealing area (as described above) really help if you have a choke point in the system (ie hole on top of case is only 24/24 sized but you are running a 30mm carb)?
Great question. The width of the opening is clearly a factor, but seems to me there’s only so much width available, so you have to rely on duration, pressure and capacity. I compare to being out in the ocean and coming up for a breath between sets of waves. Duration is how long you can take the gulp of air. The size of the opening is your cupcake hole. It affects how big of a gulp you can take, to some extent. If you’re only breathing through a straw you obviously won’t get much so you need to extend the duration. I’m pretty sure there’s a formula that explains the relationship between duration and intake opening area somewhere in one of the tuning books. If there isn’t there should be!
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Thu Mar 25, 2021 6:03 pm quote
Gracious.
Lemme tackle a few of these.
I'm too lazy to cut and paste - so its from memory.
You know who you are.
🙂

Lots of people have put PX cranks in VBB cases.
I'm not sure I have seen anyone put a P200 crank in - and grind the cases for the lip. The upside would be the enlarging of the cupcake hole - aka the inlet - in WIDTH - without going to longer inlet duration.

Longer inlet duration: If you do it on the IO (opening) side it favors mid rev. If you do it on the IC (close) side, it favors high rev. or so I am told. If you increase the inlet/crank duration overall, it generally favors higher rev.

So benefit 1 of P200 crank was wider web allowing wider inlet meaning bigger inlet hole without longer inlet durations.

Longer conrod (comes with P200 shaft) does 3 things.
1. Longer means less angle between crank and piston means less angular pressure on cylinder side walls - and rod ends.
2. Longer means more case volume for your charge. How does more case volume affect high peak and low end? Well - depends on other components like the pipe. If your pipe is designed to suck on that volume - you get more high end. If your volume increases and it doesn't have a pipe like that - it can help low end. In my case - I have a pipe that is deisgned to support some low end (off pipe) so I am guessing I will get more low end with increased volume.
3. Longer conrod means I can put an adapter between cases and cylinder and avoid welding my cases.

So benefit of longer rod in may case (pipe dependent) is I get more low end, take some pressure off crank and cylinder/piston, and don't have to weld up my cases.

Captcha - the adapter bearing I was discussing just makes the 110 rods (all P200 sized small end holes) fit a P150 sized piston pin (aka gudgeon).
Also - longer con rod as noted above makes bigger volume case, and inlet is likely the bottleneck of the system - since there are 3 transfer ports to exhale through/ exhaust port is far larger than inlet.

V-one / VR-one. It's in the mix. I love that I have my original cases running this thing - but there's an argument for it's consideration. Been waiting to see how Safis project goes.

Boss Hog (nice): I'm vested in the small block more than I would like to admit. At least one of my motors is going to remain small block to utilize all these shiny objects. wtf is KW 64/128 ? your spec'ing parts I can't even understand

BFA - Might as well put a 4 cylinder in the floor board area. They look so big! - and price matches. I am really a fan of what I see from the quatrain set up.




Reeds on my VBB cases. Just cant bring myself to grind away my original cases into a big hole for reeds.
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Thu Mar 25, 2021 6:07 pm quote
charlieman22 wrote:
wtf is KW 64/128 ? your spec'ing parts I can't even understand
Kingwelle crankshaft with 64/128 timings?

http://www.kingwelle.com/Produkte/Kurbelwellen
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Thu Mar 25, 2021 6:53 pm quote
Ah...
Yes - Kingwelle (not timings - tho) 60/128
Stroke = 60
Conrod length = 128
Thus the packers.
Craigs build is indeed a Boss.
Didn't really want the scoot down just as the weather warms.
Appreciate everyone throwing in some of their fave' spec options.
Maybe I will go electric with this.
(kidding - relax!)
Gonna have to determine a plan.
Hooked
Bodgerific 150 Super, PX200(ish...), US 50 Special in progress
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Thu Mar 25, 2021 8:02 pm quote
[url] http://www.kingwelle.com/epages/78261472.sf/de_DE/?ObjectPath=/Shops/78261472/Products/%22PX%2064-128%22[/url]

64 stroke, 128 Conrod, takes the 244 out to a 260.

Mmmmm.
Ossessionato
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VBA
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Thu Mar 25, 2021 10:16 pm quote
SaFiS: Nice catch about V-one vs VR-one. That's what I get for only looking at one and making assumptions. DOH!

Socal: You had me dying with the cupcake hole analogy. I'm sure there is a formula in one of the 2T books, but I like analogies like the one you made. In my head using made up numbers, opening your cupcake hole from 10mm to 12mm would yield you a 5% in intake duration equivalent. I wonder if someone can make a simple relationship without having to whip out a complex model. Also, if you have a restriction (ie 24/24 carb) then does opening your cupcake hole to an area bigger than the area of a 24mm circle really help you?

CM22: I thought more crank case volume reduced your charged air pressure so it wouldn't rush into the transfers as fast? Wait, thinking out loud this would keep from possibly short circuiting the fuel mixture out your exhaust at lower RPM, I think. Disregard, I think I just proved the point you were making.

CM22: How does a longer conrod, which adds more metal to the contained space, make the case volume larger? What am I missing?
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
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Thu Mar 25, 2021 10:57 pm quote
Captcha wrote:
CM22: How does a longer conrod, which adds more metal to the contained space, make the case volume larger? What am I missing?
You need to pack the cylinder higher to account for the longer rod. So going from a 105 rod to a 127 means you need a 22mm packer. So more case volume.
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Fri Mar 26, 2021 1:30 pm quote
Ginch wrote:
Captcha wrote:
CM22: How does a longer conrod, which adds more metal to the contained space, make the case volume larger? What am I missing?
You need to pack the cylinder higher to account for the longer rod. So going from a 105 rod to a 127 means you need a 22mm packer. So more case volume.
lol. My tiny brain couldn't comprehend even adding a packer so large. This thread makes way more sense.
Molto Verboso
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Fri Mar 26, 2021 2:51 pm quote
Ginch wrote:
Captcha wrote:
CM22: How does a longer conrod, which adds more metal to the contained space, make the case volume larger? What am I missing?
You need to pack the cylinder higher to account for the longer rod. So going from a 105 rod to a 127 means you need a 22mm packer. So more case volume.
22mm that's a lot of movement, exhaust and a few other parts are going to need to get moved. Any issues with the head hitting the cowl?
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Fri Mar 26, 2021 8:22 pm quote
Ok - we have a winner.

Decided: make the most of my 150 based build.
Love my original cases - mark of bodge pride-ory
Save whole hog for Boss Hog build.

Plan:
- Split cases
- Have machinist right my bearing seat
- Put in a 110 rod and tru my crank - adds case volume/ cuts stress/adapts MHR
- Small end adapter roller bearing
- 5mm lift (packer)
- Long ass studs - that is its own issue to sort
- New bearings
- Viton seals on clutch and fly side
- Replace cruciform

Help from the tuner crowd:
1. Looks like the Mazz con-rod is all that is really available in 110/60. Any other options I should be looking at?
2. What's the word on the eccentric crank pin that would take me to a 62 stroke? Would that even fit in my VBB ROTARY cases without protruding and interfering with the inlet pad?
Lemme hear what y'all think - lining up my order as I type.


Do you have to both grind the case and recut the inlet pad?? or does it still clear both


About all I can find in 110 is the Mazz. No forged ones seem to be offered. Will it fly?

Ossessionato
Joined: 26 Oct 2015
Posts: 2966

Fri Mar 26, 2021 9:14 pm quote
It would be pretty easy to sand and polish the con rod before it's assembled. It will also make the con rod stronger since sanding and polishing will remove all the ridges and stressors that were cast into it during manufacturing. Also make sure that there are oil slots in both the big and little ends of the con rod. If not have the con rod slotted by a reputable crank rebuilder.

That's all i got for you.
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Fri Mar 26, 2021 9:17 pm quote
Quote:
It would be pretty easy to sand and polish the con rod before it's assembled. It will also make the con rod stronger since sanding and polishing will remove all the ridges and stressors that were cast into it during manufacturing
Thanks brother!
Like it.
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Fri Mar 26, 2021 11:00 pm quote
Plan is missing, extend rotary inlet to 200 degrees.

62mm crank will fit. Might loose some of the 5mm packer/adapter getting the transfer timing back down on the MHR.

But we finally have a plan.
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Fri Mar 26, 2021 11:07 pm quote
Inlet duration - we'll find some additional degrees I'm sure...
Quote:
62mm crank will fit. Might loose some of the 5mm packer/adapter getting the transfer timing back down on the MHR.
Wondered about that.
I've got the 58mm kit - now possibly on a 62mm.
Are you a fan of the offset crank pin?
Jet Eye Master
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Fri Mar 26, 2021 11:23 pm quote
Welding up the big end might be a good idea with the offset pin. Could be the last rod on that crank though.
62mm is getting nearer to maximum piston velocity but that's a good thing, right?
Ossessionato
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Sat Mar 27, 2021 4:31 am quote
Nothing to add to the plan which i love, just hoping you could post a pic of the old cruciform when removed? Curious how much of a beating it's taken in it's short life of hard work on this build!
bodgemaster
63 GL, 76 Super (x 2), 74 Primavera (x 2), 06 Fly 150
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Sat Mar 27, 2021 4:56 am quote
Jack221 wrote:
Plan is missing, extend rotary inlet to 200 degrees.
Hey Jack, educate me on this. What’s the general rule with inlet time on a rotary engine? What’s optimal opening and closing, and in relation to what? How much is too much?
Jet Eye Master
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Joined: 14 Jun 2017
Posts: 2744
Location: London UK
Sat Mar 27, 2021 10:19 pm quote
SoCalGuy wrote:
Jack221 wrote:
Plan is missing, extend rotary inlet to 200 degrees.
Hey Jack, educate me on this. What’s the general rule with inlet time on a rotary engine? What’s optimal opening and closing, and in relation to what? How much is too much?
If it was just a matter of optimum numbers everyone would know them. Rotary duration has to be matched to the cylinder. Transfer duration and max rpm are relevant here. Any cylinder will run with any inlet timing but what will run best is the issue. 120/60 is usually good for something near stock. 130/90 can be better for very much non stock. Choosing inlet timing and fine tuning the cylinder to match gives the best results.
Always remember with the knowledge of the era, our scooters were made for economy and not speed, so any factory setting is usually the economy setting.
bodgemaster
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Sun Mar 28, 2021 7:13 am quote
LOL.
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VBA
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Sun Mar 28, 2021 2:55 pm quote
charlieman22 wrote:
1. Looks like the Mazz con-rod is all that is really available in 110/60. Any other options I should be looking at?
I can't speak for other manufacturers. I can say that I would have no idea where to start when at the build-a-crank store (the dude version of build-a-bear). Found some detailed specs on Mazzy website that may help you order the correct pieces.

Mazzucchelli conrod options for Vespa models. Looks to include dimensions of conrod, crankshaft pin, both bearings, and washers disc. Pic below doesn't include all Vespa's like the link, but catches what you may be interested in.

All of Mazzucchelli conrods that are 110mm in length. In case you get really creative and want to dive out of non-Vespa specific conrods. You can go back to Mazzy main site, go to products, and checkout 107mm and 115mm if you 110mm isn't the direction you end up going.
charlieman22 wrote:
What's the word on the eccentric crank pin that would take me to a 62 stroke? Would that even fit in my VBB ROTARY cases without protruding and interfering with the inlet pad?
Again, I don't have experience eccentric crank pin. It does appear though that the eccentric crank pin fully extended (at "62mm" position) would force the big end of the conrod to interfere with the inner lip of the crank. See pic below. I went to my garage and measured a Mazzy P150 crank (105mm/57mm) I have laying around, it seems like the gap between big end and lip is approximately 0.8mm-1mm.

Only way I see being able to still use the eccentric pin to full benefits would be by grinding on crank to have intake open earlier. Using intake crank timings nomenclature, the crank I was measuring opens at 6° ATDC. To avoid interference discussed above I estimated you would need to cut the crank to have intake start at 12° BTDC (-12° in SIP speak).

The next issue is that with the eccentric pin fully extended and crank intake cut larger, it puts your big end dang close to touching the rotary pad. To put it another way: On the crank I measured 1.9-2mm gap between bigend and the top sealing part of the crank. If the eccentric pin adds 2mm fully extended, you could possibly exceed the outer diameter limit of the crank. *I was using my cheapy digital calipers, and that is why I have approximate values (aka I don't trust them for when a tenth of a mm matters).

Jack may get his 200° intake wish if you have to start chomping on that intake side of the crank.


Mazzucchelli Conrod Specs (condensed)


Tight clearance between the big end of conrod and lip of crank may cause issues for fully extended eccentric crank pin.

Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Sun Mar 28, 2021 6:42 pm quote
Captcha,
Thanks for the homework!
Much appreciated.

The eccentric pin appears to be out of stock - so the discussion may be moot.
I've sent an email to Pinasco - asking for information on sizing.
they have been, let's just say, a bit slow in responding.

Jon Gick reached out to me and gave me a suggestion for a performance rod company for 2 stroke.
Their stuff looks great - but without Pinasco's specs - its hard to shop for a match!

Would like to get moving on a solution.
The Maz info - just the way its laid out - is helpful.
I will ping Pinasco again and see if I can get an answer.

Weather is getting nice here!!

Cheers.
-CM
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Mon Mar 29, 2021 12:12 am quote
With the offset pin not available - I had a quick look at off the shelf options.
A replacement 62mm crank with longer duration timings is available.
How well it would fit - is unclear...
The lip would like need to be ground off - though its possible I could shim and leave it as my cases have room on the fly side.

(When I put the existing crank in - I noted there was nearly 3mm of space on the fly side between the crank and the case. Pic below showing gap.)

If the crank below is built on the same size web (98mm) then I should be able to make it work.

Not married to 62mm - but also not that stoked about putting all this time and cost in to the existing crank shaft to move it to 110 con rod length - there is no savings when all said and done.

Question: What size bearing fits the P200 crank on the fly side? Normally on a VBB you use the same as clutch side (25IDx62OD) - but I think the P2 crank has a 24mm journal? Not sure.


This is the 62mm crank, "finely balanced", P200. I am under the impression that P200 and older 150 cases has the same size of crank web circumference.


From page 20 something. You can see a 2-3mm gap on the fly side. I could always mill down the edge of the P200 crank as well. My larger concern is weather the web circumference is the same.

Molto Verboso
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Mon Mar 29, 2021 12:29 am quote
The ID of the P/PX bearing is also 25mm. Shimming the crank over to the fly side sounds like a bad idea. How would it look at the small end bearing/piston? The lip is what gives the P200 crank the extra width for a wider inlet. Is someone able to machine the groove in the case, to accommodate the lip in a VBB motor?
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 8067
Location: Victoria, Australia
Mon Mar 29, 2021 3:18 am quote
swa45 wrote:
The ID of the P/PX bearing is also 25mm. Shimming the crank over to the fly side sounds like a bad idea. How would it look at the small end bearing/piston? The lip is what gives the P200 crank the extra width for a wider inlet. Is someone able to machine the groove in the case, to accommodate the lip in a VBB motor?
I'm pretty sure Hot Rod Al did it... CM, get in touch with him on FB and ask, he love to help (although not keen to do the work these days).
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
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Mon Mar 29, 2021 7:24 am quote
Quote:
swa45 wrote:
The ID of the P/PX bearing is also 25mm. Shimming the crank over to the fly side sounds like a bad idea. How would it look at the small end bearing/piston? The lip is what gives the P200 crank the extra width for a wider inlet. Is someone able to machine the groove in the case, to accommodate the lip in a VBB motor?
I'm pretty sure Hot Rod Al did it... CM, get in touch with him on FB and ask, he love to help (although not keen to do the work these days).
Well - it is of course my style to hunt for the corners of the envelope.
Thanks for the insight SWA. That's helpful.
My consideration of the P2 crank goes beyond the inlet width - though it would be very nice to harvest that with a groove.
It comes off the shelf with a 110 rod (desired) and 62mm stroke.
This would:
- Add some case volume
- Decrease some stress on cylinder wall (and crank pin)
- Increase my CC's due to longer stroke.

That has my interest - even if I were to machine off the edge.
In fact - even if I machined all but 1mm off the edge - I might pick up a small amount of width on my inlet over its entire length with a 1mm wider rotary pad.

Ginch!
Thanks - great idea.
I will reach out to him now.

-CM
Ossessionato
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Wed Mar 31, 2021 9:55 pm quote
Have been flipping stones.
Have an idea.
Don't know what I don't know.
Think we are gonna find out.

That bad ass 62mm crank has been calling my name.
- Case volume increase
- CC increase
- Stroke increase
- Inlet width increase
Speaking strictly on a technical level - that's a lot of increase.

Got a few suggestions - from those that didn't answer - WHY?
But they seam complicated, so instead, I took a P200 and VBB crank and brought them to a tooling cutter I know.

They are the ones that have a grinding machine that dresses automotive crankshaft journals.
Showed them a VBB crank - and a P200 - and we looked at if they could fit it to their grinding machine. Looks like a yes.

So my plan is to take a P200 crank, and regrind all the journal seats to match a VBB crank. Then I can just insert it like I would a normal VBB crank - no change to bearings or seals.

I will need to cut a groove in the case - but I think that is doable with a mill.
Not sure how tough this is going to be to do a really good job with.
Quick measure of similar cases suggests the thickness is no different than a P200 so if I can cut it - the meat should be there... SHOULD...

Finally - I will have to change my SIP vape flywheel to a PX taper - but SIP is out of stock.
Then I had this weird recollection that at some point Swiss got shipped a dozen of them?! Is that possible? (Swiss! check you PM...)

Gonna see if I can execute on an order tomorrow.
Is this plan all wet for some reason I haven't considered?
Jump in and yell at me if you have any thoughts/concerns.


Fly side


Clutch side

Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
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Thu Apr 01, 2021 3:28 am quote
A couple thoughts on this plan...

First, Swiss was an Honest Citizen, let SIP know the mistake, and got the extra flywheels back to SIP. I know this because I hit him up a while back, too.

Second, unless your machinists work pretty cheap, how much is all this going to cost you?

You're already pushing the limits of what's going to be possible on a rotary valve, so you should plan to drop another $500 for a reed block and some VForce4's and just bite that bullet while you're at it. That way, you also don't have to worry about sealing surfaces and can just blow the whole path wide open. You can also swap to a bell crank for increased crank case volume and torque while you're at it.

And one thing I noticed when I pulled up my notepad for SIP is that they're backordered on pretty much every part I had flagged for my GL/P200 project. Crank, Exhaust, solid rivet tool, reed manifold...it's like the whole world has also decided to build a crazy P200 motor this spring.
Molto Verboso
2007 Stella 225
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Thu Apr 01, 2021 4:32 am quote
Didn't you have a P200 motor sitting around somewhere?
Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
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Location: Nashville
Thu Apr 01, 2021 4:47 am quote
Christopher_55934 wrote:
Didn't you have a P200 motor sitting around somewhere?
I have one. It came out of JVB's now-electric P200. I may throw it into my Sprint for the time being while I continue to work on the GL and wait for parts to become available for the motor project.
Ossessionato
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Thu Apr 01, 2021 5:19 am quote
This is just ludicrous!

And chandler is right. The 100 lbs box of magnets went back to sip! barely a thanks from them for returning 1200$ unsolicited! Ha
Ossessionato
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Thu Apr 01, 2021 7:20 am quote
Ok - a couple votes for -" what are you smoking CM?"

Reed: Makes sense, however - I just don't want to do it!
I'm not certain why - perhaps its the sound, or the carb sitting way up high over the motor under my small cowls.
Just call me a traditionalist.


Cost: Actually... Someone called Pinasco directly and waited on hold and got to their product guy and showed him a video online of the failed crankshaft bearing and convinced him to send him the 62mm replacement after agreeing to pay for shipping. So new crank is "right priced". ¯\_(ツ)_/¯

The machine work will be about $120 for grinding the crank.
The case work - probably ~$200 for the groove.
From there forward - all P200 cranks will fit and I will have an unfeasibly large inlet hole (remember you are an adult, and this is a family forum, not Playboy Forum).

Nothing else really changes.
All the other parts I need are in stock - std bearings and seals after I do this work.

There is however some risk of course...
The crank or the cases could be trashed by any mistakes in machining.

Would a reed work better?
Maybe - I don't know.
Not sure there is a 62mm read crank - but it would save me the time/risk/cost of cutting the groove - and the is the riskiest most expensive machining process I have to pay for.

Off to order parts.
If it all falls to pieces- there is always the summer swap meet.
Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 3170
Location: Nashville
Thu Apr 01, 2021 7:38 am quote
Nice job working the phones
charlieman22 wrote:
Not sure there is a 62mm read crank - but it would save me the time/risk/cost of cutting the groove - and the is the riskiest most expensive machining process I have to pay for.
You mean like this 62mm reed crank? That one is out of stock, but the version without a polished conn rod is currently in stock.
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 2233
Location: california
Thu Apr 01, 2021 7:41 am quote
Ha! You will force me to think it through!

BTW - Swiss - damn - you good samaritan!
Just when I needed a miracle.
Luckily the wife is in Europe - and the one place that has them in stock can ship to the UK.
See if she will mule for me.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1672
Location: UK (South East)
Thu Apr 01, 2021 8:08 am quote
CM, you're right, the reed noise is 'unmistakable' to say the least. However, mine fits easily behind my cowl ie. no clearance issue if that's what concerns you? Yours is a VBB, mine is a VBC. Maybe it's because the S&S reed block in combo with a PWK 35 AS is particularly compact??
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 2233
Location: california
Thu Apr 01, 2021 9:06 am quote
SWA - thanks.
Might be that your combo is more compact.
My prior fittings using a lifting block from a MMW reed to adapt it - had the carb right up to the top of the cowl.

I suppose I am also holding on to my custom made intake - perhaps not for the better.
I love it's simplicity - but I really have no data to show its better or worse.
Just a visual preference I suppose.

A reed certainly opens wider than I will achieve with this - though I will achieve a wider opening than you could with a 150 case normally - using the lip of the crank and a cut groove.

I could try and do a quick calculation to see if I have a full 28+mm of total surface opening. I suppose once I reach that I have removed any bottle neck from an inlet size perspective.

One thing I am interested in is to grind the cases - just after the inlet - to allow fuel flow "above" rather than just through the crank webs. I have a set of cases that Vader had ported - Kristian from Bar Italia passed on to me.

Vader was porting them for reeds - but check out the work in the area shown below. I think I could apply this thinking to my rotary cases.
What do you guys think??!!


Vader created a better flow path here. The stud in this case is in the way a bit - but on mind it is closer to the inlet - giving me plenty of meat to cut into safely


My actual cases - from my prior build. Some room here to open up my volume and flow path. With crank in open position - the volume is not insignificant.

Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1672
Location: UK (South East)
Thu Apr 01, 2021 1:09 pm quote
CM, I'm assuming that a VBB crank has a step in the right place on the clutch side to retain the bearing? On a PX, there is a retaining circlip on the crank side of the main bearing. The oil seal is seated onto the circlip and is closest to the crank. Do you have this in your plan? Could the bearing possibly shift laterally without the requisite retention?
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