small and large block case varieties
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Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 4503
Location: San Diego, CA
Thu Oct 15, 2020 9:28 am quote
OK, so let's say you were going to build a bike from bits and had a choice of cases.

small block stuff (some may be redundant here)
-p series 3 port
-125/150 with 3rd port cut and some porting by a p.o.
-p150
-px150
-stella150 reed
-2 port cases

large block
-200 cases

Said hypothetical engine would go in a VBB, and I'm thinking something like birdsnest built - pinasco 177, etc. (which is 2 port but sounds like he's really enjoying). Let's say I'm definitely not going down the high revving screamer route this time.

The deal is I don't understand the difference in all of these cases. I've only been exposed to the later P stuff and small frame stuff. What are the advantage / disadvantage of these? Which ones have 2 or 3 ports? Which ones use the split crank bearing? Should I care? It seems easier to me, but I've never tried splitting or reassembling with the full bearing on the crank. The engine would be premix, so autolube isn't a concern.

Is there a reference out there somewhere that breaks down what changed and when in the case varieties? I tried search but this one is hard to figure some key words for that will get you the right search result.

Last edited by sdjohn on Thu Oct 15, 2020 12:20 pm; edited 1 time in total
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1531
Location: UK (South East)
Thu Oct 15, 2020 10:56 am quote
Older P/PX cases, small block, decent 177/187 setup would be my preference. The older ones have more material for the Dremel to carve out, no electric start hole to fill, and they will take an EFL gearbox if you can get your hands on one. They are 3 port by design and have the later crank bearing setup, giving you a wide range of crank options. My 2 cents
Ossessionato
Joined: 26 Oct 2015
Posts: 2685

Thu Oct 15, 2020 11:08 am quote
You know me....i would swap in a stock big block 200 every time (and 24/24 carb). No cussin, no fussin, case closed. Reliable 65mph+ with zero tuning or mixing and matching parts. Engine rebuild (bearings, seals, and other wear items) would be very straighforward and a very quick turn around time. Then you have to ask if you want to step up to a 10" wheel conversion though. I have a 61' Allstate (essentially a VBB) with a stock P200, 10" wheels, PK fork, and a semi-hydro disc brake. It rips. I can hop on the highway and just go with no worries.
Enthusiast
'66 Sears Cruisaire Smallframe
Joined: 12 Aug 2019
Posts: 73
Location: York, PA
Thu Oct 15, 2020 11:11 am quote
Oh, does the P200 actually have a different block? I didn't know that; I assumed it was just a different cylinder.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 4503
Location: San Diego, CA
Thu Oct 15, 2020 11:19 am quote
yes the p200 studs are in different locations, among other things

so the 3 port small blocks have more kits available, it seems

any reasons to go 2 port or is the 3 port a no brainer?
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1531
Location: UK (South East)
Thu Oct 15, 2020 11:23 am quote
WDC, my preference is always a 200 based motor, but they are getting increasingly difficult to find for reasonable money, at least here in the UK. Maybe not such an issue for John
Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 2852
Location: Nashville
Thu Oct 15, 2020 11:25 am quote
I guess the main question is what kind of build you're looking for, other than "not super-high-revving."

Personally, I'd probably start with a P200 and build on that (but I don't have the past trauma you do on that front).

If you're thinking torque-y, wide powerband based on 150 cases, you'll want a 177 (so 187 with the 60mm crank), a box, probably the Polini, and longer gearing. I'd avoid any 2-port cases, both because you're losing transfer area and because you lose the P-style seals and bearings, which, make splitting the cases infinitely easier.

While it's not fully dialed in, the difference between my sprint motor (24/24, long stoke Polini 177) and my VBB motor (24/24, long stroke 2-port pinasco) with basically identical port timings is definitely there. That extra area in the cases makes a difference.

Are you keeping the 8" wheels? If so, *really* long gearing

If you're going to build up the gearing, you should also go with the EFL gearbox, since it's a better design. And throw in a Cosa clutch for smoother, softer performance.

This all assumes you're going to stick with an SI carb. If you're going to run a side draft, I'd probably swap to a reed and jump on either Malossi or LML/Stella reed cases.

The planning stages are always fun, because it's all dreams and upside and no blood or frustration yet
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1531
Location: UK (South East)
Thu Oct 15, 2020 11:29 am quote
John, I would go with a 3 port. Could be anything from late Sprint V to 90s PX. I would personally avoid anything with a narrow taper crank, which rules out the 2 port motors. It's easy enough to swap in a pre-P kickstart quadrant to keep it looking right
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 4503
Location: San Diego, CA
Thu Oct 15, 2020 11:33 am quote
the idea is: torquey wide power band, SI carb, 8" wheels

I want the equivalent (if there is one) of my DR135 on the small frame - easy to live with, torque across the rev band, not hard to tune, etc. No fuel pumps or crazy crap this time

I'm game for whatever port matching is required, but it looks like not so much work on small blocks.

I'm not even sure I want to open the intake timing, but I probably will have a hard time not doing that
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 4503
Location: San Diego, CA
Thu Oct 15, 2020 11:43 am quote
chandlerman wrote:
I'd avoid any 2-port cases, both because you're losing transfer area and because you lose the P-style seals and bearings, which, make splitting the cases infinitely easier.
This kind of feedback is exactly what I was hoping for, thanks Chandlerman.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
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Location: London UK
Thu Oct 15, 2020 11:45 am quote
Some of the small block 177 kits will work as 3 port without the base port in the case. The third port flows up through the piston.

Although, small block PX with a BGM187 would be my choice.
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: 7954
Location: Victoria, Australia
Thu Oct 15, 2020 1:39 pm quote
Jack221 wrote:
Although, small block PX with a BGM187 would be my choice.
Got to agree with Jack (and SWA) here. Easy to work on, put in a nice EFL and you're good. And the BGM. Love mine. It's a great cylinder, unfussy, and as much torque as you could want.
Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 2852
Location: Nashville
Thu Oct 15, 2020 2:36 pm quote
I'm on Team BGM, too. super-wide power band on a box. I can only say specifically about the SIP RoadXL, but it's a little low on the clearance front on my VBB. It's going to get swapped for my Road 2.0 once I'm back into wrenching mode.
bodgemaster
63 GL, 76 Super (x 2), 74 Primavera (x 2), 06 Fly 150
Joined: 26 Sep 2013
Posts: 5477
Location: So Cal
Thu Oct 15, 2020 3:33 pm quote
I agree with Jack the difference between 2 and 3 ports isnít terribly noticeable with kits that flow the third port thru the piston. Youíre welcome to come down and take the yellow rocket for a spin anytime. 3 port Pinasco, 20/20 w/bellmouth, cut crank, stock gears, 23 tooth cog. And rockin 8ís, of course. Solid 65mph scoot.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 4503
Location: San Diego, CA
Thu Oct 15, 2020 4:03 pm quote
Ah thanks for reminding me Socal, I have had a rip on old yellow during our desert excursion - she's awesome. that's the 3 port Pinasco? It thought you ran all Polini. I'm in. That's the exact kind of deal I'm after, and if I am near to yours the jetting will certainly go easier

Can I run a P200 clutch and cover on the small block cases? I still have the banded clutch and S&S cover from the P.
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: 7954
Location: Victoria, Australia
Thu Oct 15, 2020 5:30 pm quote
sdjohn wrote:
Can I run a P200 clutch and cover on the small block cases? I still have the banded clutch and S&S cover from the P.
Yes. There's a lot more similarities than differences tbh.
bodgemaster
63 GL, 76 Super (x 2), 74 Primavera (x 2), 06 Fly 150
Joined: 26 Sep 2013
Posts: 5477
Location: So Cal
Thu Oct 15, 2020 6:18 pm quote
john - Yellow has a Pinasco in it now. Polini with a new Gran Sport is on the shelf waiting for a hone. IMO the Polini produces more power than the Pinasco, which has more of a ďstock plusĒ feel, but both are plenty fast. That all goes out the window though if you start grinding ports and making other mods. Youíll love the 8ís though, guaranteed.

Last edited by SoCalGuy on Thu Oct 15, 2020 6:32 pm; edited 1 time in total
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 4503
Location: San Diego, CA
Thu Oct 15, 2020 6:32 pm quote
Thanks SoCal, i donít have to decide on a kit today but am glad for the input. I did some games with gearing numbers too and it seems with a bit of work any of the common gearboxes can be made to work out for 8s. Mostly Iím figuring out what to ask for parts wise since there is some degree of choice for the base.
bodgemaster
63 GL, 76 Super (x 2), 74 Primavera (x 2), 06 Fly 150
Joined: 26 Sep 2013
Posts: 5477
Location: So Cal
Thu Oct 15, 2020 6:34 pm quote
If you can find a Veloce case nab it.
Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 2852
Location: Nashville
Thu Oct 15, 2020 7:17 pm quote
SoCalGuy wrote:
If you can find a Veloce case nab it.
Make sure they're the later veloce cases, though. Otherwise, you wind up like me with the small cone crank and bearings, having to order the special large cone crank from SIP to get a decent ignition.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1531
Location: UK (South East)
Fri Oct 16, 2020 12:12 am quote
We just need Sime66 to chime in and you'll have the full compliment of the MV BGM 177 appreciation society!!
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: 7954
Location: Victoria, Australia
Fri Oct 16, 2020 2:13 am quote
SoCalGuy wrote:
If you can find a Veloce case nab it.
Late Super also has the P flywheel bearing.
Molto Verboso
2007 Stella 150
Joined: 02 Nov 2019
Posts: 1114
Location: Rochester, Minnesota
Fri Oct 16, 2020 4:32 am quote
If your putting together a shopping list for wide torque, look at a BGM touring or lth vortex box exhaust also. They're great for torque below 5500 rpm. I was doodling on a notepad and looking at the numbers compared to my SIP road xl. On a p200 both have about 4% more torque at 5500 rpm and 12% more torque in the 5000 rpm range. At about 6000 rpm the road xl is about even. Look for dyno comparisons with a torque curve, especially if you plan on turning anything into the 6000 rpm range, torque starts to fall off quickly.


As for cases what are you try to accomplish? I have a small block reed valve lml with a DR177. It's interesting if you want to do a sustained 60mph. Not easy to do, you might get to 60mph or 65mph on a flat, but wait until you get some wind or a hill. On the other hand the 177 was great around town, especially with gearing that didn't make 1st worthless.

The p200 with a non ported, very mild Pinasco 225 setup gets to 60 mph without an issue. IE I've done no port matching at all to the single boost port yet and there is a pretty significant mismatch. The case port is maybe 50-75% of the cylinder. There is a Malossi 210 sport or touring setup that seems to be popular, takes some porting to the case but has lots of torque for those of us who don't want a high rpm screamer.

Last edited by Christopher_55934 on Fri Oct 16, 2020 5:41 am; edited 1 time in total
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
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Location: UK (South East)
Fri Oct 16, 2020 4:40 am quote
John knows all about the Malossi 210 Sport

Agree re: Pinasco 225. Nothing mind blowing, but the power is very satisfying. Regarding your DR177, I'm a firm believer in long stroke cranks for that little bit extra. No replacement for displacement all all that. Longstrokes are not often recommended for the DR177 for some reason, but make a big difference with other kits eg. BGM177
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