I've Got A Hunch...

The original 2-stroke Genuine scooter and its 4-stroke manual and automatic offspring

Moderator: Modern Buddy Staff

Post Reply
User avatar
az_slynch
Member
Posts: 1806
Joined: Wed Sep 12, 2012 4:56 pm
Location: Tucson, AZ

I've Got A Hunch...

Post by az_slynch »

Recently picked up an '81 Honda Passport as a project to further broaden my queue of projects. Besides, I'm still in OE Zuma Parts Limbo/OE Helix Parts Limbo/OE Vespa GT Parts Limbo and I figured I'd start working on the Passport in the interim. One of the things I considered was swapping out the original 70cc 3spd semiauto engine for a Lifan 125 4spd semiauto engine. 12V electrics and a CDI ignition would be a nice upgrade too.

So, in looking at the Lifan motors, I noticed some similarities with the 4T Stella top end. After poking at some online business journals, I noted that back in 2006, Lifan was looking to buy into LML (Lohia Machinery Limited) to get a piece of the Indian market. Maybe it happened and they did some tech transfer?

I need to do a bit more research, but the bore/stroke of the 4T Stella is identical to the Lifan 150 (crank is most likely different). The cam and cam chain orientation is identical to the Lifan and from parts book views, even the the chain guides look similar.

If the top end "is" Lifan or similar enough, this could definitely move the performance possibilities on the 4T Stella up, as there are larger bores than 170cc and 4V cylinder heads out there. Here's to hopin'! :D
At what point does a hobby become an addiction? I'm uncertain, but after the twelfth scooter, it sorta feels like the latter...

Seriously...I've lost count...

Seven mopeds ...that's still manageable...
User avatar
Drum Pro
Member
Posts: 1163
Joined: Thu Sep 01, 2011 4:03 am
Location: Victorville, Ca.

Post by Drum Pro »

If you could see me now I'm doing my "Happy dance". It's a step in the right direction for the 4T.
User avatar
jimmbomb
Member
Posts: 801
Joined: Fri May 20, 2011 1:00 am
Location: St Louis

Post by jimmbomb »

Keep at it,az.....if your research gives us parts for a 200+ 4t stella..then im selling my p200 and getting another stella..
Im tired of the dim headlight and weak brake. .but I love the get up and go.
Keep at it.. find us options! Thanks.
J H
[URL=https:///]Image[/URL] upload pics
Rusty J
Member
Posts: 109
Joined: Mon Apr 23, 2012 5:04 pm
Location: L.A. Beach Cities, CA

Post by Rusty J »

No kidding?!

171cc (or bigger) with a 4V head might be possible with bolt-on parts? That's a game-changer, if there's a clutch that can handle the increased torque.
User avatar
viney266
Member
Posts: 2270
Joined: Thu May 19, 2011 8:49 pm
Location: westminster md
Contact:

Post by viney266 »

is the 4t clutch the same a 2T? If so, then that is covered. I put an SIP clutch in my 2T stella and it works GREAT...not cheap, but worth it.
Speed is only a matter of money...How fast do you want to go?
User avatar
az_slynch
Member
Posts: 1806
Joined: Wed Sep 12, 2012 4:56 pm
Location: Tucson, AZ

Post by az_slynch »

viney266 wrote:is the 4t clutch the same a 2T? If so, then that is covered. I put an SIP clutch in my 2T stella and it works GREAT...not cheap, but worth it.
The 4T Stella has a 7-spring clutch like a P200. The difference is in the drive gear, which is a 21T like the 2T Stella. SIP makes a 22T gear for the 7-spring clutches that would give a small (4%-ish) upgear across all four gears, presuming that the cush drive is a 68T gear. Still need to tear down a motor and do tooth counts for all gears one of these days. Collecting gaskets from Genuine has been like pulling teeth so far (buying through my dealer), so I'm holding off until I have everything needed to rebuild afterwards.
At what point does a hobby become an addiction? I'm uncertain, but after the twelfth scooter, it sorta feels like the latter...

Seriously...I've lost count...

Seven mopeds ...that's still manageable...
Rusty J
Member
Posts: 109
Joined: Mon Apr 23, 2012 5:04 pm
Location: L.A. Beach Cities, CA

Post by Rusty J »

One point about the clutch: The 4T engine has similar average torque compared to the 2T engine, but the peak torque is about twice that of the 2T. It has to be, as the same average torque is concentrated in a once-every-two-revolution power stroke instead of distributed evenly between once-per-revolution power strokes.

So we need a clutch rated (in 2T engine use) for about twice the nominal torque of the 4T engine, or it'll slip during the power stroke.

I may be underestimating the effectiveness of the cush drive, however. The 200cc version apparently uses a redesigned clutch; if it's interchangeable, that may be the way to go.
User avatar
viney266
Member
Posts: 2270
Joined: Thu May 19, 2011 8:49 pm
Location: westminster md
Contact:

Post by viney266 »

That is what I have i my 2t. The SIP "house brand" clutch. Its a cosa set up they they make. VERY tough and works like a charm too. It was right around 200 bucks for the whole thing,but worth every penny IMO
Speed is only a matter of money...How fast do you want to go?
User avatar
viney266
Member
Posts: 2270
Joined: Thu May 19, 2011 8:49 pm
Location: westminster md
Contact:

Post by viney266 »

That is what I have i my 2t. The SIP "house brand" clutch. Its a cosa set up they they make. VERY tough and works like a charm too. It was right around 200 bucks for the whole thing,but worth every penny IMO
Speed is only a matter of money...How fast do you want to go?
User avatar
slotrod65
Member
Posts: 473
Joined: Wed Dec 05, 2012 9:28 pm
Location: Albany NY

Post by slotrod65 »

This is great news! I will be following this thread for more....
User avatar
Stilts
Member
Posts: 281
Joined: Thu Jun 23, 2011 7:33 pm
Location: Baltimore, MD
Contact:

Post by Stilts »

Yes, yes, and oh, YES.

Keep that great eye of yours looking, az_slynch!
Image
User avatar
slotrod65
Member
Posts: 473
Joined: Wed Dec 05, 2012 9:28 pm
Location: Albany NY

Post by slotrod65 »

Any update on this az-slynch?
User avatar
az_slynch
Member
Posts: 1806
Joined: Wed Sep 12, 2012 4:56 pm
Location: Tucson, AZ

Post by az_slynch »

My colleague with the injured 4T (collapsed inner valve spring) has refused any work on it until his modern-Vespa-of-miscellaneous-and-sundry-bits is reliable as well as rideable and there is available garage space to take his 4T over and drop the motor. I have all the gaskets, just want to tear it down and get the spring specifications so I can find performance springs for it (since he winds on it like it was a 2T).

My 4T is still in a box at my local dealer. Been waiting for a work performance bonus payout for about four months now so I can get it paid off and take it out of the carton.Tax refund should be coming soon too. I'll break it in, buy new top-end seals and then crack it open to see what's what.
Last edited by az_slynch on Fri Mar 28, 2014 6:00 am, edited 1 time in total.
At what point does a hobby become an addiction? I'm uncertain, but after the twelfth scooter, it sorta feels like the latter...

Seriously...I've lost count...

Seven mopeds ...that's still manageable...
User avatar
BuddyRaton
Scooter Dork
Posts: 3887
Joined: Sat Sep 09, 2006 10:08 pm
Location: Boca Raton, Florida
Contact:

Post by BuddyRaton »

viney266 wrote:That is what I have i my 2t. The SIP "house brand" clutch. Its a cosa set up they they make. VERY tough and works like a charm too. It was right around 200 bucks for the whole thing,but worth every penny IMO

I'm not a fan of the cosas. I had one asplode after 1,000 miles on CBR 2012. Yeah I ran the snot out of it but still. The MMW basket is much beefier.
"Things fall apart - it's scientific" - David Byrne
www.teamscootertrash.com

'06 Cream Buddy 125, 11 Blur 220, 13 BMW C 650 GT, 68 Vespa SS180, 64 Vespa GS MK II, 65 Lambretta TV 175, 67 Vespa GT, 64 Vespa 150 VBB 64 Vespa GL
User avatar
slotrod65
Member
Posts: 473
Joined: Wed Dec 05, 2012 9:28 pm
Location: Albany NY

Post by slotrod65 »

Thanks, I am very interested to hear what you find...
User avatar
Neurotic-Hapi-Snak
Member
Posts: 335
Joined: Thu Jun 05, 2014 2:56 am

Post by Neurotic-Hapi-Snak »

So, any word on if Stella 2T/Vespa PX/P200 transmission parts fit in the 4T? The 4T, IMHO, needs an up gear and even stock has the torque to pull slightly taller gears.
User avatar
az_slynch
Member
Posts: 1806
Joined: Wed Sep 12, 2012 4:56 pm
Location: Tucson, AZ

Post by az_slynch »

Neurotic-Hapi-Snak wrote:So, any word on if Stella 2T/Vespa PX/P200 transmission parts fit in the 4T? The 4T, IMHO, needs an up gear and even stock has the torque to pull slightly taller gears.
The gear stack is essentially the same as the 2T. If you want slightly taller gearing, you could try a 22T, 7-spring clutch gear. That would net you about 4% taller gearing across all four gears. Easiest upgrade.
At what point does a hobby become an addiction? I'm uncertain, but after the twelfth scooter, it sorta feels like the latter...

Seriously...I've lost count...

Seven mopeds ...that's still manageable...
User avatar
Neurotic-Hapi-Snak
Member
Posts: 335
Joined: Thu Jun 05, 2014 2:56 am

Post by Neurotic-Hapi-Snak »

az_slynch wrote:
Neurotic-Hapi-Snak wrote:So, any word on if Stella 2T/Vespa PX/P200 transmission parts fit in the 4T? The 4T, IMHO, needs an up gear and even stock has the torque to pull slightly taller gears.
The gear stack is essentially the same as the 2T. If you want slightly taller gearing, you could try a 22T, 7-spring clutch gear. That would net you about 4% taller gearing across all four gears. Easiest upgrade.
That's what I was thinking, a 22 tooth clutch gear with everything stock. Maybe the Malossi upgear kit or a custom gear stack if I ever put in the 165 kit.
User avatar
Neurotic-Hapi-Snak
Member
Posts: 335
Joined: Thu Jun 05, 2014 2:56 am

Post by Neurotic-Hapi-Snak »

So what size clutch basket does the Stella have? Isn't it 115mm like the P200E, not 108mm like the older PXs? I know it uses the newer PX EFL transmission. Also the Malossi upgear kit would be a 16% upgear on the EFL transmission with the 21T clutch/68T primary, not the 8% on the P200E with 23T clutch/65T primary.

SIP sells a DRT 23 tooth clutch gear that works with the 68 tooth primary. Maybe I should try that, it should be about an 8% upgear, correct?
Post Reply