Vintage vespa with sidecar
Post Reply    Forum -> Not-So-Modern Previous123...272829...353637Next
Author Message
Addicted
Honda elite
Joined: 19 Jun 2007
Posts: 972
Location: California
Sat Mar 14, 2020 3:09 pm quote
one time many years ago at a Vegas Rally I saw this dude showing off. He started up his scooter and started revving the living bejeesus out of it. Moments later it stopped.
Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1985
Location: Staten Island, NY
Sat Mar 14, 2020 3:31 pm quote
That sucks and I feel for you as that was literally me 7 months ago. Learning patience and caution is the biggest takeaway from messing with these engines for extra power. You destroy one cylinder or piston and you quickly learn to take it very cautious!

I'm sure you'll be back on the road in no time.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1972
Location: London UK
Sat Mar 14, 2020 6:49 pm quote
Well that's a surprise development. Can't wait for the pictures.

These can be really harsh. You just have to love them.

I think there is a chance the 1.8mm hole in your carb is too small. I'll bet the FMP recommended 2.5mm would have saved it. Yay science!

3rd time lucky it is....
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Sat Mar 14, 2020 7:56 pm quote
Everyone has their own style.
Mine is a touch more wide open than some...

Was doing my version of speed jetting.
Run WOT and check top speed data + butt dyno on same stretch.
Start way rich - and step down jets after each run.
Gets faster and faster with ea run until it stops improving.

There's one catch.
When you get close - you gotta watch temps.
This cylinder seizes at 311.
I was a bit too focused on top speed...
Sloppy.

But sometimes even a blind squirrel finds a nut.
When I rolled to a stop and let clutch out - there was no compression.
Suspected I would find rings trapped in slots when I opened it up.
Was not disappointed - but a little surprised - little scuff here - little aluminum there.
Rings trapped by a bit of aluminum but not so bad.

Gotta admit. Little tempted to grab some muriatic acid - clean up the rings - and Re-assemble.
I mean, after all, I did figure out what main jet it takes!

https://youtu.be/17ig4WziQzM?t=19

IMG_9764.JPG
Piston - hard to tell one seize froth next - but hey - I Swiss cheesed this thing so much - what is a little scuff here or there?

IMG_1475.jpeg
Close up under magnification of ring. If I had a new set in the garage I would make these a bracelet - but is that cleanable? Looks like just a bit of piston left on the ring.

Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1985
Location: Staten Island, NY
Sat Mar 14, 2020 8:04 pm quote
parts ordering is gonna get scarce for a while so you better make it last! No SIP deliveries for the foreseeable future. Hopefully you can reuse that and if not, find some replacement rings locally to hold you over.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1972
Location: London UK
Sat Mar 14, 2020 8:25 pm quote
If you could have got that started that would have worn off. Out with the acid and running by lunchtime. Got away with it for sure.

I know you are trying to do this all on your own. A few things that will save time. CHT may have been at 311F when it seized but that is a perfectly safe temperature, if its accurate. Engine was detonating, which gets the piston very hot in a few spots but the CHT stays the same. To seize from detonation on your set up you were at least 10 points under on the main jet, minimum. This is not a bit out its a mile. Only trying to help.
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Sat Mar 14, 2020 8:38 pm quote
Quote:
I know you are trying to do this all on your own. A few things that will save time. CHT may have been at 311F when it seized but that is a perfectly safe temperature, if its accurate. Engine was detonating, which gets the piston very hot in a few spots but the CHT stays the same. To seize from detonation on your set up you were at least 10 points under on the main jet, minimum. This is not a bit out its a mile. Only trying to help.
Help is good.
Help is welcome.
This cylinder - with the GS piston seized at same temp previously.
In fairness - both times - 310 was after coast down to stop.
It's hard pull the clutch, right the bike, and check the temp all at once...
So perhaps it was 320. IDK.

The failure mode is identical to prior soft seize.
Front and rear - over boost and exhaust.
Piston oblongs when hot.

Temps with larger jets on WOT were 272 max - CHT.
Step down to 132 from 135 was too much in this case.
But I may not be understating your insights.

Are you suggesting I should have been up at 142?
Is this reference to enlarging hole in carb?
Not beyond putting back together with larger hole and running again on 132 - with closer eye on temp - if that's the case.

What's your take?
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1972
Location: London UK
Sat Mar 14, 2020 9:40 pm quote
They're just not as sensitive as they are made out to be. The lesson here is you are way weak. not one jet size but many. Piston top should be near black all over just to get close to rich enough, you've seen the pictures.

The fastest jetting for a 2 stroke is as rich as it will go. All the lean down crap is from 4 strokes. One size down from just spluttering at WOT is it. Done. If you can't get spluttering at WOT there is an issue with fuel delivery. Could be anything but when correct a big jet splutters like un-rideable.

We know the hole in the float bowl is an issue. A loose 2.0mm is minimum over a 125MJ, 2.5mm definitely works (careful not to go through). This is not a 'nice to have' it's essential. If your sure your float level is at maximum before dribbling, then that's ok.

Get you good ear to listen out for detonation noises when at WOT. They were there. The faint tinkling noise of impending doom.

Last edited by Jack221 on Sat Mar 14, 2020 9:49 pm; edited 1 time in total
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Sat Mar 14, 2020 9:49 pm quote
145 tended to just not want to rev out - with an occasional hesitation when dumped on full throttle - rather than splutter.
I never threw in the 148 to see if it spluttered - cause I was headed the other direction.

Consider it drilled.
Tks!
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Sat Mar 14, 2020 9:52 pm quote
forgot:
Am I re-honing to clean up walls of cylinder- or just scrubbing with muriatic acid?
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1972
Location: London UK
Sat Mar 14, 2020 10:12 pm quote
Start at 148 next time. Be sure there is the fuel line down the carb level of WOT splutter and you're good to go.

What you were seeing was 145MJ level of richness at mid throttle and restricted flow at WOT. Don't go by the numbers go by how rich it is. Also be aware some jets are duds. Say they are a 135 and run like a 125. Always need this in the back of your mind.

Acid clean should do it. Can see you running in from the beginning after a hone.
Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1985
Location: Staten Island, NY
Sat Mar 14, 2020 10:37 pm quote
Question cm, was this the carb you are running with right now?

https://www.sip-scootershop.com/en/products/carburettor+dellortospaco+by_285204t7

The description says they drill the hole 1.5-1.8mm for 177 kits and 2.0mm for 200 kits. The description also says this specific one is for p200 so I assume it's drilled with 2.0mm hole. You checked yours and it's not 2.0mm? This is the hole that goes from float bowl to where the mj sits?

I'm thinking I need to check mine now and make sure it's 2.0mm before I run the engine.

Edit: correction, it says modified for quatrini polini 177 so yeah it's probably got the too small hole. Just need to make sure which one I'm opening up before I do it.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1972
Location: London UK
Sat Mar 14, 2020 11:33 pm quote
Remember when they talk about kits and cc they are meaning virgin kits bolted on, not tuned, widened and with holes cut in the skirt, running twice the BHP.
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: 7560
Location: Victoria, Australia
Sun Mar 15, 2020 2:30 am quote
Jack221 wrote:
Out with the acid and running by lunchtime...
Abso friggin lutely.

(but do it in a wind tunnel if possible - the stuff is wild)

I'm not sure that the hole drilling is such a black and white issue. What about all those kitted scooters that have un-drilled carbs? They don't all seize.
A 1.8mm hole is equivalent to a 180 main jet.
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: 7560
Location: Victoria, Australia
Sun Mar 15, 2020 2:45 am quote
I should also say - how do you know that SIP haven't done exactly what you're suggesting, and getting the Smartcarb people to tailor a few packages. I guess SIP know a lot more about scooter engines than Smartcarb do. So that may be a question for your list as well.

If Smartcarb do the calculation, my concern is that Vespas don't put out as much hp per cc as the rest of their customers bikes. Whodats will know much better than me, because I'm always surprised at the size of the carbs they run, way bigger across the range per cc by a pretty big factor. I imagine that would make their experiences and judgment a bit redundant in this case, but happy to be proved wrong.
Estimated current horsepower ought to be one of their questions.


Sorry about your seize... my first I had no idea! I heard this weird noise and eventually worked out it was coming from the back tyre. Eventually I pulled in the clutch and the noise stopped. Cause and effect, it's like science, you know?
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1597

Sun Mar 15, 2020 4:12 am quote
CM this is getting extremely interesting, Iíve done extensive jetting on 4 stroke engines but this 2 stroke jetting is on an entirely different playing field. I can see what Jack means by the piston needing to be black on top, clean piston means lean lean lean.
Addicted
Honda elite
Joined: 19 Jun 2007
Posts: 972
Location: California
Sun Mar 15, 2020 7:54 am quote
Darn Charlie if that's the worse of it doesn't look too bad? Seems like you can have that cleaned up in an hour? Did you have the foam Polini filter ON when this happened?
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Sun Mar 15, 2020 8:47 am quote
Gents - really good stuff - and damn glad to have the opinions/input.
I stretched it too far and didn't pay attention to the temp.
Not good.
Jack - I think you have it 95% - but I don't think this cylinder and piston can run over 310 based on some pretty good data.
Prior seize was on stock Polini - at same temp somewhere around there at mild RPM as I came off throttle (idle jet seize).
Cause of seize was identical - piston gets oblong - and seizes front and back.
I gave a little extra hone on this build and mic'ed piston and cylinder to ensure I had upper end of tolerance for clearance.
This cyl with GS piston (with holes added) simply does not like to get over 300.

With the tear down - we have a bit more info and Jack's insights align with what I am seeing.
- Top of piston doesn't lie - it was running lean.
- Pause during rev is in fact mid range not top - that better describes it. Thanks. Rich through the middle. Starved at top apparently - at least with that small jet I had in it...

I may have a secondary issue.
See pics.
Had noticed a leak around the exhaust for past week and assumed I needed to torque clamp better. Tore down with head parallel with bench - wanted to see that there were no leaks and avoid any dripping as I disassembled head.
Found this ( see below)


Other:
Swiss - Carb I am using is the "T5" not the "T7". Yours is the T7 - has a 2mm whole. Mine has the 1.8.

Ginch - perfectly described lock up. Me to myself: hmm - what is that strange screeching sound? why is my back wheel starting to slide out to the left? Oh! I should pull the clutch now... Its like slow motion! Had so much time to think about it this time that I actually thought to pull clutch slowly and ready myself for the bike to straighten out quickly. Gladly very low drama really.

Hibbert - I didnt have the box top on - was swapping jets frequently and just trying to get rough jetting done quickly...

Now have to assemble with stock Polini head instead of MMW nice squish or...
Here comes the BGM?

IMG_4782.JPG
Mystery spluge

IMG_6857.JPG
Piston top - lean.
Was looking for head leak - none evident past head gasket

IMG_3572.JPG
Flipped head - found this - looks like leak but kinda weird pattern.

Screen Shot 2020-03-15 at 9.41.40 AM.png
Close up of head sealing area near that weird looking leak. That looks like a cracked head to me

Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Sun Mar 15, 2020 9:34 am quote
Oh, and smart carb people.
They absolutely have worked with SIP. they have a good every mans solution in their mind.

Iím just cognoscente of the realities of new product category launches. There will be things learned.
There will be improvements.
They have already learned some stuff.

I figured if we could get to the source and hear what the gives and takes were, then this crowd might just be smart enough to make it the ďSmarter CarbĒ.

SIP tested and dynoíd so itís not done totally blind.
Similar to DRT modíed carb I just scortched my motor with (again - 132 too small!)

But my set up may benefit from the 2.0.

Funny. The smart carb guys have a spec for 1.8 on 25mm.
I donít know what that spec is for - but I have a hunch it refers to a hole that feeds the float.
One of the things Iím digging in to learn.
Wonít surprise me if that number goes to 2.0 at a certain size of carb.

Still pursuing. Will share back.

Off to read simeís thread to try and learn simplest means of any porting I might do on a nikasil cyl.

Comments on apparent crack?
bodgemaster
1963 GL, 1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 5246
Location: So Cal
Sun Mar 15, 2020 10:07 am quote
Quote:
Comments on apparent crack?
Damn you, crack.
Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1985
Location: Staten Island, NY
Sun Mar 15, 2020 10:17 am quote
You guys are talking about the hole to the right inside the float bowl right?

I just measured the right hole into main jet stack by sticking micro drill bits in until they just barely fit. 1.8mm bit just barely fits in the main jet passage. 2.0mm bit won't fit there. In the choke jet passage to the Left a 2.0mm bit fits. I've got 2.0 and 2.4mm bits. I should go open it to 2.4mm using the bit by hand right? On the mj hole.

IMG_20200315_141627.jpg

Addicted
Honda elite
Joined: 19 Jun 2007
Posts: 972
Location: California
Sun Mar 15, 2020 11:22 am quote
you were doing speed trials without the top?
Addicted
Honda elite
Joined: 19 Jun 2007
Posts: 972
Location: California
Sun Mar 15, 2020 11:23 am quote
swiss1939 wrote:
You guys are talking about the hole to the right inside the float bowl right?

I just measured the right hole into main jet stack by sticking micro drill bits in until they just barely fit. 1.8mm bit just barely fits in the main jet passage. 2.0mm bit won't fit there. In the choke jet passage to the Left a 2.0mm bit fits. I've got 2.0 and 2.4mm bits. I should go open it to 2.4mm using the bit by hand right? On the mj hole.
I've drilled mine to 2.0mm with a 3/8 Milwaukee drill motor!
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Sun Mar 15, 2020 12:18 pm quote
Speed runs without the top: sure! Itís all about how rich or lean u r. Now I was too lean - but if I had the top on it would have just put the same experiment in a different bracket. No magic there as far as I can see.

Swiss: thatís the hole and it appears u have the T5 or they did not drill urs properly. Arenít you p2 cases?

Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1985
Location: Staten Island, NY
Sun Mar 15, 2020 1:39 pm quote
charlieman22 wrote:
Swiss: thatís the hole and it appears u have the T5 or they did not drill urs properly. Arenít you p2 cases?
No I've got this carb for my stella LML 150 cases.

I'm gonna drill it out to 2.4mm.

P2 cases are sitting on the shelf waiting for the stella to be finished and running safely for a month or so.
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: 7560
Location: Victoria, Australia
Sun Mar 15, 2020 6:18 pm quote
charlieman22 wrote:
Looks too straight to be a crack to my eye. I'm sure you could come up with a diy dychem test.

Too soon for the BGM! Wait until you totally destroy the Polini first.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1972
Location: London UK
Sun Mar 15, 2020 7:27 pm quote
All that black running from the exhaust (Spooge) is normal when the lower rpm range is way too rich. With the carb drilled the main jet at WOT should be smaller. This will help. Get the pilot jet right and it will stop. No amount of tightening will stop the black spooge, it will go when the jetting is correct.

Looks like a scratch to me. Spooge makes the non O ring heads leak as well.
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Mon Mar 16, 2020 3:39 pm quote
Crack or scratch (my stage name), SoCal made a donation in kind of some GS rings - which means I am just going to hone the cylinder, swab down the piston, use the new rings, and start all over again.

Corona virus willing - smart carb is on the way - with bracketed metering rods.
He said he didn't think I would need them - but was up to provide them for a bit of learning. Will share back results and insights to him as a return on the bracketing.

BGM cyl looks questionable to me. Witness mark on the cylinder looks like the piston was sitting inside and oxidized a little. Pic below after acetone wipe down. Going back.

Which brings us to this moment... wait for it...
I'll need to get a reed kit as my intake.
Like Malossi for simplicity - bolt on.
Like Pollini for reed selection
(Both as per Ginch).
When I went to look at getting BGM replaced - I thought of one other solution.
For about the same cost as buying the reed kit ( I am rounding here), I could get the Quatrini M1XL. Thats the one with the cylinder intake. It comes with full reed set up I think.

Trade off's I've thought of:
- Cant use SI on it.
- No idea if this works well with smart carb
- Doesn't have secondary hole for CHT (Hate CHT getting in way when taking plug out)
- Does have more aggressive piston design
- May not fit cases - recall seeing some crazy angular ports?

Cylinder pros - what say you?
Wrong crank - not as good touring - ???
BGM or Quatrini as my move up when I manage to kill the Pollini through bad decision making?

Screen Shot 2020-03-16 at 4.32.50 PM.png

IMG_5109.JPG
Blemished cylinder means this one goes back. What replaces it?

Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1888
Location: Veria, Greece
Mon Mar 16, 2020 3:59 pm quote
What about the new alu Malossi??
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Mon Mar 16, 2020 4:05 pm quote
Safis - don't know it.
You're insights often align with mine - (only mine are formed from reading yours... ) e.g. Streamline Seats. 🙂
What do you like about that one?
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: 7560
Location: Victoria, Australia
Mon Mar 16, 2020 6:26 pm quote
I would have run the cylinder like that, but then, I have no patience.

What are the port timings on the Quattrini? You want plenty of torque as the number 1 priority... sadly I have no experience with them. Wish that wasn't so!
One thing that I do often wonder about with cylinder induction is - does the intake get in the way as far as cooling is concerned?

Malossi should definitely be on your radar as they are good stuff. I've ridden 2 177 MHR's and they were both amazing. But nobody I know has a Sport - the only one you should consider. So I don't know... there is probably something on the GSF but haven't really looked as yet.

Clipboard01.jpg

Ossessionato
Joined: 26 Oct 2015
Posts: 2454

Mon Mar 16, 2020 8:29 pm quote
I suppose you could mount a CHT sensor under one of the cylinder head nuts?
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1972
Location: London UK
Mon Mar 16, 2020 8:37 pm quote
Still don't think you're ready for this. Maybe buy another scooter?

Once we get you through setting up the Polini with the SI24/24 it should do 70mph with the sidecar. Wouldn't think this needs to be any faster. Another scooter could be a 200, then you could start with the real adrenaline. I ride my sportsbikes at 160mph+ (when no-ones looking) but my MHR up around 90mph is properly exciting.

The Malossi 187 is going to be the fastest for a small block.

I'm with Ginch, I would run that BGM. However, that BGM without any Dremel work is probably slower than your Polini.
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Mon Mar 16, 2020 9:25 pm quote
Ok - well - this is going somewhere I hadn't anticipated - like
Reader's digest. We are probably just days if not hours from lock down.
Man needs a project.

BGM cylinder blemish posted above - would likely be fine after three strokes of the piston in all reality. Agreed.
Wouldn't put on without giving it the Sime treatment for power.
Editors note: Sime - this is purpose of example only - I promise not to hold you accountable for target timing I am unhappy with. 🙂

Mercato has the 3118005 double ring version (think this makes it the Sport?) in stock at about the same price as the BGM give or take.
So price not driving this - that bridge already crossed.

Ginch - your pic above is cylinder induction. the 8005 is case induction. Have I got the wrong kit ?

Jack - why the BGM over the Malossi? If Malossi makes the power? You got something against the Italians?

BTW - specs below - timings very tame - assume usual packers and head gaskets would bring it up and allow 60mm crank (I have the Pinasco in). Any reason to believe 60mm crank would not work with this?

Whodat - lord knows any place but under the damn spark plug in my second life.

SoCal's rings show up at my door tomorrow in the mail. The Polini is going back together and remains my work horse - but I have time on my hands and a choice of cylinders on the wall to tweak while we are locked in.

A spare set of cases is only a few blocks away - so who knows - maybe I even build up on another. BGM looks pretty spectacular to me as well - so haven't really got any axe to grind. Just give you guys a chance to choose the cylinder you will be advising on.
🙂

*Edit: Jack; is there any more certain way to sway me to Malossi then stating it will be more powerful? You do know how this works right?

Screen Shot 2020-03-16 at 9.32.56 PM.png
the three options from Malossi site

Screen Shot 2020-03-16 at 9.22.53 PM.png

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: 7560
Location: Victoria, Australia
Mon Mar 16, 2020 9:54 pm quote
charlieman22 wrote:
I could get the Quatrini M1XL. Thats the one with the cylinder intake. It comes with full reed set up I think.
charlieman22 wrote:
Ginch - your pic above is cylinder induction. the 8005 is case induction. Have I got the wrong kit ?
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Mon Mar 16, 2020 9:56 pm quote
Wait.
Is that a Quatrini on your bench?!
You know you're not really helping right?
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: 7560
Location: Victoria, Australia
Mon Mar 16, 2020 11:28 pm quote
charlieman22 wrote:
Wait.
Is that a Quatrini on your bench?!
You know you're not really helping right?
Not mine! That's just to show how the intake might block the air from the fan.
So did you mean to say not the Quattrini with the cylinder intake? I'm confused.

You know, the BGM straight out of the box might surprise you. It would be an interesting experiment to do a before and after, especially if you (we) can get to grips with the GSF Dyno. Could be beneficial for many people here to know ... and soak up some hours in which you may be otherwise burdened with Honeydo stuff.

After a quick look on the GSF, here is the info I was after!
abtreter wrote:
I did another test again.
The new Malossi Sport against the BGM.
Bought both cylinders this fall. Both cylinders are unprocessed. Edit (12/15/1: Overflow valves of the BGM cylinder are open.
The engine block is the same - the cylinders were tested in quick succession.

The transfer valves are adapted to the BGM. And to exclude everything, I then adapted the transfer ports to Malossi and reduced the pinch gaps by 0.1mm
Practically made no difference.
Molto Verboso
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 1208
Location: california
Mon Mar 16, 2020 11:57 pm quote
Quote:
Not mine! That's just to show how the intake might block the air from the fan.
So did you mean to say not the Quattrini with the cylinder intake? I'm confused.
Ahhh - so mesmerized by cool looking intake I failed to grasp your visual example of how it sits in the air channel... interesting point.

What I was really looking for in hindsight was: is cylinder induction the bees knees?
From the responses - and Malossi not using it with new kit (now that I have studied up a little) seems like cylinder induction is okay - but nothing to die for.

Really interesting find from GSF. Much appreciated!
Saw Sime drew out the data on Hibbert's thread from his vid for dyno.
Suspect I could get a fairly consistent area to run the same test.
No idea if I could figure out how much my rig weighs tho!

All the parts on the way.
Will see if shipping is shut down before it all arrives.
Otherwise - its gonna look like Scooter-Center West.com over here.

The bigger technical question now is:
If they tell us that we are not allowed to go out on the empty, wide open, car free roads, unless its for "an essential need" - would running speed test for this group and recording fall under that exemption?
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: 7560
Location: Victoria, Australia
Tue Mar 17, 2020 2:18 am quote
Which parts are on the way? You say "all parts" - from some of your previous confessions it could really be ALL parts!

My thinking on cylinder induction:
It avoids bottlenecks in the Vespa intake location because of lack of area
It avoids a bottleneck in that the intake is situated just above the clutch side crank web and basically directed right at it
It allows you to use a full circle crank which may be more easily balanced
It means that the path of fuel/air to it's destination is longer because it goes down into the crankcase first and then back up again

There are not many cylinder-inducted new two strokes being made these days, most of them seem to be crankcase inducted. Not talking about teensy little openings like ours, but big stonking ones. That probably says something about which is "best", but also may be due to production cost as well...
BFA's cases have an inlet that is very similar to this current style by having the intake at the very base of the cylinder.
That's it at the top with the screw part way in -

From above -


But big dollars obviously... next best thing, and something that will take your roving eye for a shiny new scooter part Charlieman, is the Malossi cases.
They've moved one of the case bolts that was there and replaced it with a lovely big hole. All that extra air only costs a little bit more! Gets you past the crank very neatly and puts it as close to the base of the cylinder as possible with a modest budget.



That's quite a big gap between crank and case. So full circle crank is no issue.
https://www.sip-scootershop.com/en/products/crankcase+malossi+vrone+for_57183820

.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1972
Location: London UK
Tue Mar 17, 2020 2:36 am quote
From these various latest examples of the quickest way to spend your money, it's easy to see that the thing about cylinder induction is that it's not really big enough. If happy with average or on only on a small cc cylinder it works well enough but for big power it just doesn't have the size and this is one of those situations that is all about size.

For selecting crank type crankcase compression is one of the factors. Too much is not good for torque. This would need some detailed investigation to see what might go best with what.
Team Scooter Trash for Petfinder Foundation   vespa scooterwest scooter west Motorsport Scooters   AF1 Racing Vespa Austin
Post Reply    Forum -> Not-So-Modern Previous123...272829...353637Next
[ Time: 0.4611s ][ Queries: 27 (0.3218s) ][ Debug on ]