2007 Stella P200 Motor Install
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Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
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Tue Aug 25, 2020 12:55 pm quote
Christopher_55934 wrote:
Out of curiosity, the area of my exhaust port is 42.54mm x 27.96mm = 1189 mm

35mm is the inner diameter of the exhaust stub, so the area is 962mm, that means the port in the cylinder can flow more and is a funnel at this point. Which is what I was starting to notice while cleaning it up.

When do you stop making the port larger?
When the math says you can

figure that if you increase the ID of the exhaust port to 39mm (so increase it 2 mm all around), that puts you at 1194 mm^2, which is pretty much a match for area. I didn't measure it exactly, but I definitely took a a couple mm off the walls of the exhaust port on the VBB's Pinasco when I opened the port up, although I didn't specifically calculate and set a target.
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2007 Stella 150
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Tue Aug 25, 2020 1:01 pm quote
I got a return email from Pinasco, about the two different heads A3610 and A3611. I could be in for a long email conversation to get an answer. The language barrier could be an issue. I specifically wrote I had a Pinasco 60 mm crankshaft. The return email asked what stroke motor I had. 😳
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2376
Location: London UK
Tue Aug 25, 2020 1:23 pm quote
Christopher_55934 wrote:
I feel inadequate, yours is 6 mm wider than mine, back out to the garage I go. 😁

That's a port width of 77%.
Port width is 70% chord width, not arc width, on your type of piston ring. So max is 54mm but as said aim for 52mm, as going over max requires adult supervision and careful attention to shape.

Port area and stub area are more dynamic than they appear. Most of the exhaust flow has occured by one third open (approx). The full area is for the low pressure functions, like the baffle wave assisting transfer etc.
Molto Verboso
Vespa
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Tue Aug 25, 2020 1:41 pm quote
Porting looking great Chris glad you decided to work on it think it will be worth it.

Do you have a degree wheel to check the inlet duration?
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2007 Stella 150
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Location: Rochester, Minnesota
Tue Aug 25, 2020 5:16 pm quote
Jack221 wrote:
Christopher_55934 wrote:
I feel inadequate, yours is 6 mm wider than mine, back out to the garage I go. 😁

That's a port width of 77%.
Port width is 70% chord width, not arc width, on your type of piston ring. So max is 54mm but as said aim for 52mm, as going over max requires adult supervision and careful attention to shape.

Port area and stub area are more dynamic than they appear. Most of the exhaust flow has occured by one third open (approx). The full area is for the low pressure functions, like the baffle wave assisting transfer etc.
What do you mean by chord width vs arc width? I have been using chord width straight across the front of the port. Not the width measured flat on a piece of paper using a trace for example.

Will have to work on the port width a bit more. I spent a few hours cleaning, polishing and blending everything back to the stub. Adding another 4 mm to one side would get both to 14 mm. Giving me a port width of 46.5 mm. Then remove ~ 3mm more each side getting me to a width of ~ 52.5 mm. That would put me about 11 mm from both ports.

How far back do you blend when removing the much material? What does the port look like from the top? Do you go for a funnel shape? Working from inside the exhaust port I would think it would almost have to look like a funnel. That is what I started noticing when I was cleaning up.What I had.

The other issue could be getting to close to the intake ports. The left is 14 mm from one and the right was 18 mm from the other. How close is to close? I thought I read something about short circuiting, and the intake going right back down the exhaust.

I'm going to try it as is with a cleaned up exhaust port for today. I've spent to much time cleaning up ports today, running out of patients. I'll get a few dyno runs and jetting dialed then. Then open up the port and see what the change does, will be interesting to see the data point.

Cleaned up the piston getting rid of any flashing remains from the casting process. Used a small and medium sanding drum to clean up radii etc.

My clutch parts came in today and I had to know what the compression was without that 1.5 mm base packer. Another reason I said enough port work for today. Made a 0.12 mm aluminum base gasket from shim stock. That is easier to cut than a soda can. I bought a set of hole punches so the 5 holes were easy enough also. The compression is 185 -190 PSI, that on the higher than I normal aim for side and that's on a cold motor. It feels like 185, harder to kick them the 177. I usually aim for 150 psi for street use. Definitely not taking anything off the head squish band ring to reduce squish. Surprised it was that high with that large of a squish.
My DR had a large squish and a lower psi about 120. Removed a few mm off the head squish band, got down to 1 mm squish and bumped the compression up to 150 psi.

It has a Kytronik so will take advantage of that with the higher compression retard it a bit more at higher rpm.

I don't have intake numbers, ran out of time and didn't want to pull the flywheel today. I have a piston stop and all that good stuff, I'll find TDC if it's not already marked to verify timing with a timing light. With an assembled motor how do I find intake timing? I've only done it on !y Stella with reeds so I only had to measure the cylinder.

I think that's it for today I need a shower finally cooling off and have just about stopped sweating.
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
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Location: california
Tue Aug 25, 2020 7:40 pm quote
Christopher - looks good from my chair.
Just FYI - my measure are all taken on flat paper.
Trace - lay flat- measure.
You can compare your current width by doing the same on your trace.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2376
Location: London UK
Wed Aug 26, 2020 12:17 am quote
Couple of quick points. Exhaust port should not funnel at the top. From bore to stub should have no lumps. Fully straight. Sides will always funnel as the studs are in the way.

PSI compression is a little meaningless on a 2 stroke. For 4 stroke great. 2 stroke pointless. Need to calculate by measurement. Full capacity and only above the exhaust port. So there are two calculations for a 2 stroke. Both relevant in different ways.
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2007 Stella 150
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Location: Rochester, Minnesota
Wed Aug 26, 2020 2:40 am quote
Jack221 wrote:
Couple of quick points. Exhaust port should not funnel at the top. From bore to stub should have no lumps. Fully straight. Sides will always funnel as the studs are in the way.

PSI compression is a little meaningless on a 2 stroke. For 4 stroke great. 2 stroke pointless. Need to calculate by measurement. Full capacity and only above the exhaust port. So there are two calculations for a 2 stroke. Both relevant in different ways.
Thank you, that is what I meant for the shape. Flat on top and the sides funnel down. A dustpan maybe? 😁
Ossessionato
Joined: 26 Oct 2015
Posts: 2619

Wed Aug 26, 2020 6:34 am quote
Jack221 wrote:
PSI compression is a little meaningless on a 2 stroke. For 4 stroke great. 2 stroke pointless.
huh?
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2007 Stella 150
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Thu Sep 03, 2020 1:37 pm quote
Finally last part is here, SIP reinforced basket.

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2007 Stella 150
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Fri Sep 04, 2020 4:17 pm quote
Clutch is in, with a 23 tooth gear.

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2007 Stella 150
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Sat Sep 05, 2020 5:09 am quote
Out to the Garage I go
Out to the Garage I go will report back in a few hours.
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2007 Stella 150
Joined: 02 Nov 2019
Posts: 1003
Location: Rochester, Minnesota
Sat Sep 05, 2020 11:16 am quote
Heart transplant complete need to figure out carburetor.
Motor mounted, transmission oil full, wiring adapted, two stroke oil added to tank, ran fuel through hose until it ran blue. Mixed at 50:1 or 2%. Now to figure out the fuel line which is a bit short and the throttle cable.


Anybody know the factory Stella throttle cable and sheathing length? I bought this but I'm not convinced it's long enough.


https://www.sip-scootershop.com/en/products/cable+kit+phb+for+vespa+125_94110000

I have a spare throttle cable that is 79" and should reach. Could extend the sheathing with a piece of spare sheathing if I can find some. Maybe I can find a piece of tubing to slide the two ends into for alignment and heat shrink the hole joint thing together.

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Cables are a few inches short, so is the fuel line. When I figure out the throttle cable and pull, the tank for new sheathing, I'll replace the hose or add a 90 metal bend there instead of a long fuel hose loop.

2020-09-05_12-08-34_131.jpg
Connected green to green with white stripe from headset. Soldered and heat shrinking applied. Next time I pull the tank I'll just pull these into the frame.

2020-09-05_12-00-39_647.jpg

Ossessionato
Joined: 26 Oct 2015
Posts: 2619

Sat Sep 05, 2020 12:41 pm quote
I'd recommend to just get the throttle cable and sheathing from a bicycle shop. You can buy it in bulk length. The cables also have a very smooth action for a very nice throttle return.
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2007 Stella 150
Joined: 02 Nov 2019
Posts: 1003
Location: Rochester, Minnesota
Sat Sep 05, 2020 12:45 pm quote
whodatschrome wrote:
I'd recommend to just get the throttle cable and sheathing from a bicycle shop. You can buy it in bulk length. The cables also have a very smooth action for a very nice throttle return.
I was thinking the same thing, I just measured my Malossi throttle cable sheathing and it is 65.75" or 1670mm. Found an old reference that says a P cable sheathing is 62" or 1574mm. That extra length would be great if the lengths are correct.

Looks like I might be pulling my gas tank sooner than later.

This says 62" also, another reason to pull the tank and give it a try.

https://www.scooterwest.com/vintage-vespa-throttle-cable-w-solder-nipple-62-inches.html
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2007 Stella 150
Joined: 02 Nov 2019
Posts: 1003
Location: Rochester, Minnesota
Sun Sep 06, 2020 10:46 am quote
Christopher_55934 wrote:
whodatschrome wrote:
I'd recommend to just get the throttle cable and sheathing from a bicycle shop. You can buy it in bulk length. The cables also have a very smooth action for a very nice throttle return.
I was thinking the same thing, I just measured my Malossi throttle cable sheathing and it is 65.75" or 1670mm. Found an old reference that says a P cable sheathing is 62" or 1574mm. That extra length would be great if the lengths are correct.

Looks like I might be pulling my gas tank sooner than later.

This says 62" also, another reason to pull the tank and give it a try.

https://www.scooterwest.com/vintage-vespa-throttle-cable-w-solder-nipple-62-inches.html
The length dimensions are correct for a Stella also, the Malossi cable is 3.75" or about 96 mm longer and fits. I did have to shorten up the 90 fitting, I needed more cable length to fit the TMX 30. I didn't want to cut a new cable unless necessary. The throttle side was a perfect fit didn't have to touch anything. The throttle does have enough movement to open the slide wide open.

The choke conversion thread I started is correct and I was able to hook up to the TMX 30 and use the adapters and cabling. The SIP choke handle replaced the Stella perfectly.

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I sanded off about 4mm or 1/4" off the long side, the cable adjuster screws into. Then sanded more off the adjuster itself.

2020-09-06_10-28-04_169.jpg
The bend is a right fit to get the cable fitting through. Took it apart and slid each part on and it all fit together good.

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2007 Stella 150
Joined: 02 Nov 2019
Posts: 1003
Location: Rochester, Minnesota
Sun Sep 06, 2020 11:11 am quote
I think there is a fuel pump in my future, I poured a gallon of fuel in before fuel ran into the carburetor. The fuel comes in the top of the carburetor, the bend coming into the top is to high I think. Not much I can do about that. Removed the oil tank for now. This allowed me to have enough fuel line since I wasn't trying to go around the oil tank. I have the petcock on reserve so thats not the issue.

Anybody ever try one of the small electric pumps? Thinking I have plenty of room in the area under the tank for one now.

Will a vacuum fuel pump work If I tap into the adapter under the carburetor on a rotary valve motor?

https://www.mrp-racing.de/MRP-30mm-rotary-valve-intake-largeframe-Vespa-PX-T5-Sprint-Rally-VNB
Ossessionato
Joined: 26 Oct 2015
Posts: 2619

Sun Sep 06, 2020 11:47 am quote
If you're not using the air bellows anymore, you can always run your fuel line through that large opening. It will at least get rid of that loop in the fuel line. Another trick is to use a longer rear shock bolt spacer, so that it will effectively lift the fuel tank higher up from the carb.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1514
Location: UK (South East)
Sun Sep 06, 2020 12:33 pm quote
Why does the inlet manifold need the big block underneath it? Seems excessive and almost as big as a reed block. Can you not just use one of the Malossi manifolds, which would lower the carb and improve fuel flow?

https://www.sip-scootershop.com/en/products/intake+manifold+malossi+for_22158000
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2007 Stella 150
Joined: 02 Nov 2019
Posts: 1003
Location: Rochester, Minnesota
Sun Sep 06, 2020 2:02 pm quote
swa45 wrote:
Why does the inlet manifold need the big block underneath it? Seems excessive and almost as big as a reed block. Can you not just use one of the Malossi manifolds, which would lower the carb and improve fuel flow?

https://www.sip-scootershop.com/en/products/intake+manifold+malossi+for_22158000
Just a guess, I was thinking the same thing. The carburetor sits tipped a bit currently, the fuel bowl is touching cylinder plastic engine shroud. If the carburetor sat any lower the top would be worse. I

I'm also thinking about a molded plastic 45, that would take the loop over the carburetor completely out. If I were really good I'd find a fuel fitting with a female end I could slip over the carburetor fuel inlet to reduce height even more.

Something like this maybe, I could cut out a molded curve.

https://www.amazon.com/Universal-Molded-Fuel-Line-Rubber/dp/B07C8YTNPF/ref=pd_bxgy_2/141-5445264-3280506?_encoding=UTF8&pd_rd_i=B07C8YTNPF&pd_rd_r=47029597-26c2-4f37-8da6-ec41c1f472e0&pd_rd_w=3DCbw&pd_rd_wg=Cw42m&pf_rd_p=ce6c479b-ef53-49a6-845b-bbbf35c28dd3&pf_rd_r=ZCJ9FWW69V1PG10VG0ZC&psc=1&refRID=ZCJ9FWW69V1PG10VG0ZC

Last edited by Christopher_55934 on Sun Sep 06, 2020 2:58 pm; edited 1 time in total
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2007 Stella 150
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Sun Sep 06, 2020 2:43 pm quote
It runs, a few videos.


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Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1702
Location: california
Sun Sep 06, 2020 3:14 pm quote
Christopher - lookin good.
Been through this dance myself.
Different carb - and a bit risky - but my solution was to angle the carb more aggressively.
You can probably find specs for your carb's max tilt angle online.
Mine was supposed to be 20 some odd degrees - but it went to 45 without issue.
I had to adjust the float level.
Many of these carbs are put on motorcycles and tilt pretty heavily down.
The tilt allows it to clear the cylinder on our scoots.
I then got brave and cut my expensive intake manifold kit down to nothing - getting rid of the block entirely.
You can see I drilled holes for the direct mound to the cases - and reshaped the footing.
I also "reshaped" the manifold tube - if you wanna call band-sawing it off reshaping.
TBH - not sure I would recommend unless you can find how steep you can go with the angle of the carb. Also - you have to cut your intake manifold kit down to a nub... Super happy with yow mine came out - but coulda been a disaster.

I also pulled the fuel inlet all together and replaced it with a brass elbow from the hardware store.
This I would recommend - and suspect you can do even better as there will be options online for your Mikuni.
Mine had a pressed in one from the factory (not screw in).
To pull it - you screw a drywall screw in to to the brass inlet - put a vice grip on it - and use a small hammer to tap it out.
I put a new one in that was an elbow - and used JB weld to assure it would stay.
Ugly but functional in my case.

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You can buy these for $5 in or close to the size you need.

IMG_7447.JPG
Mine is bonded in with JB weld.

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This is the manifold after a few adjustments

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Shaped to match cases

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I added holes so I could use the studs and go directly on to the cases without the block - considerably lowering the carb.

IMG_7190.JPG
Posted elsewhere - but here for reference - you can see the approximate angle needed to clear everything.

Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1702
Location: california
Sun Sep 06, 2020 3:16 pm quote
Hey - Awesome!
Just saw your vid after I posted...
If your carb hits the frame when you go over bumps, you can twist it a little to help it clear.
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2007 Stella 150
Joined: 02 Nov 2019
Posts: 1003
Location: Rochester, Minnesota
Sun Sep 06, 2020 4:48 pm quote
whodatschrome wrote:
If you're not using the air bellows anymore, you can always run your fuel line through that large opening. It will at least get rid of that loop in the fuel line. Another trick is to use a longer rear shock bolt spacer, so that it will effectively lift the fuel tank higher up from the carb.
Good ideas, I have a 54 mm or whatever the longer spacer in there already. I hope to use that hole for an intake hose to pull air from under the seat.
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2007 Stella 150
Joined: 02 Nov 2019
Posts: 1003
Location: Rochester, Minnesota
Sun Sep 06, 2020 5:17 pm quote
Went out and measured, the fuel tap and carburetor fuel inlet are the same height. Getting that bending loop out I should be able to run to empty almost.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
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Location: UK (South East)
Sun Sep 06, 2020 10:46 pm quote
I have no experience with the TMX carbs, but a PHBH 30 would work fine with the Malossi manifold and a ~45 degree tilt. No fuel pump required, at least with the Pinasco level of tune. The other feature of the PHBH is an adjustable fuel inlet/banjo and a choice of float valves. I think I swapped out the 200 for a 300 on mine (need to look back at my notes), in order to sort the flow with no pump. Not much use to you as you have the Mikuni and MRP manifold, but good to document nevertheless
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2007 Stella 150
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Mon Sep 07, 2020 6:56 am quote
swa45 wrote:
I have no experience with the TMX carbs, but a PHBH 30 would work fine with the Malossi manifold and a ~45 degree tilt. No fuel pump required, at least with the Pinasco level of tune. The other feature of the PHBH is an adjustable fuel inlet/banjo and a choice of float valves. I think I swapped out the 200 for a 300 on mine (need to look back at my notes), in order to sort the flow with no pump. Not much use to you as you have the Mikuni and MRP manifold, but good to document nevertheless
I run a PHBH in my 70cc scooter, I like them. This came running with the TMX 30 with a power jet. I want to give it a try. The TMX is a 2 stroke carburetor by design. It does have two needle and seats options that I know of 2.5mm for gravity and 1.8 for fuel pump. Going to try the 2.5mm to start with. Just need to keep, the bowl full and I'm running some large id fuel line also. Just need to get rid of that loop, to start with.
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2007 Stella 150
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Posts: 1003
Location: Rochester, Minnesota
Wed Sep 16, 2020 5:13 pm quote
Checked the voltage out of the stator and at higher RPM it gets to 14+ vac. Purple lighting wire is still hanging around doing nothing. Battery voltage did go up 0.2 volts after riding around, so it works for now.

Installed my AFR sensor and took Stella for a short ride. That TMX 30 looks to be pretty darn close to dialed in for short around town riding. AFR is about a 13.4 at idle and goes to about a 11.8 under throttle. Interestingly enough the AFR is stable with this setup. No real bouncing around, it is easier to read. Need to mark the throttle positions and see what I get at 1/4 , 1/2 , 3/4 and wot.

Temperature stayed under 200f or 93c around town.

Need to install my SIP 2.0 speedometer, with tachometer and temperature then see what happens. Need to run the wiring from the headset to left side cowl for power and tachometer input.

Just from my short ride a few miles around town, Stella has more torque. Felt like she wound out quickly but who really knows until I get a tachometer hooked up again.

Then I'll build a GSF Board and see where Stella is for a baseline.
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1702
Location: california
Wed Sep 16, 2020 5:20 pm quote
Well - I have certainly gotten good stuff outa my GSF board! (nicely done).
Sounds like you are pretty close - perhaps a little rich - based on temp and sub 12 AFR.
Interesting that it seams more stable (AFR).
I wondered if the bouncing I saw was actually a good reflection of changing AFR based on SI (perhaps it has variation).
Will be interested to test my Smart Carb and see if I get less movement.

Suspect you will have no trouble pulling along at 60-65 with this set up.
Look forward to seeing how you like it on the open road.
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2007 Stella 150
Joined: 02 Nov 2019
Posts: 1003
Location: Rochester, Minnesota
Mon Sep 21, 2020 5:36 am quote
Should I put in a smaller pilot jet?
So far Stella has been running fine with the P200 motor, she does have a TMX30 carburetor and AFR meter. AFR Meter says a little rich with about a 11.8. She starts on 1st kick cold without the choke on, the idle is high then slows down to a low idle after about 20 seconds. My question is do you guys think I should reduce the pilot jet size since it starts cold easily even after sitting for three days? The meter saying rich and easy cold start makes me think I should down jet the pilot a size.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2376
Location: London UK
Mon Sep 21, 2020 2:00 pm quote
The best test to check the pilot jet size and air screw setting is to open the throttle wide on the stand, then quickly close it. The engine should instantly rev up high (like 6000). After should fall to tickover quickly and not stall.

If the jet or screw is too lean the rev up will bog flat and not rev so high. If too rich on the jet or screw it might splutter on the way up or stall on the return.

When you get this right it really helps with adjusting the needle, while making it nicer to ride.
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2007 Stella 150
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Posts: 1003
Location: Rochester, Minnesota
Mon Sep 21, 2020 2:55 pm quote
Jack221 wrote:
The best test to check the pilot jet size and air screw setting is to open the throttle wide on the stand, then quickly close it. The engine should instantly rev up high (like 6000). After should fall to tickover quickly and not stall.

If the jet or screw is too lean the rev up will bog flat and not rev so high. If too rich on the jet or screw it might splutter on the way up or stall on the return.

When you get this right it really helps with adjusting the needle, while making it nicer to ride.
I'll have to get a video of it once I close up my headset. I don't have anything to compare it too, to make that judgement.

The cold start video didn't work, this is a warm start.

https://youtu.be/-Vmaelxfs2o

Another short video.

https://youtu.be/nZMSkcTroM8
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