Modern Vespa

Hi everyone.
First of all - thank you all for sharing the enormous amount of information and experience here. Bring very new to Vespas - I have found a lot of answers here. Thank you.
I have an issue with a new to me Vespa.
I have searched for threads and topics here and didn't seem to find a definitive answer, so, I'll ask here. And if it's repetitive- I am sorry.

I obtained a 2008 Vespa LX150 with 5700 miles on it. It is a project - the bike starts, idles rough and won't accelerate past 15mph.
There is also an intermittent knocking coming from the engine. Drained oil - there are copper shavings/flakes in it (previous owner stated that knew about that, but didn't have time/desire to look into it).
Previous owner also stated that he cleaned the carb. I assume, rough idling doesn't have much to do with engine knocking/shavings - my thoughts are - clogged jets. Sprayed carb cleaner around the carb - no changes in the idling.
Attached is the picture of a strainer with copper flakes.
Asking for advice on what parts to order, what could it be.
Variator, belt, clutch, weights - all look good, clutch bell, however, hasn't been replaced since the assembly.
Thank you for your time

Sounds like you have a minimum two problems. Fuelling and a dodgy bottom end. Copper flakes indicates to me bearing materials. This could be the bike has been run with low or no oil in the past.

The knocking could be excessive play in the main bearings, so that would be my first start. A strip down of this type may or may not be within your spannering abilities. If not phone a friend or get some help.

Once you are sure the bottom end is clear and all the small oilways are free of that debris, then you can start on the fuelling

that's the big end bearing of your crankshaft going away.

it'll probably be cheaper, easier and faster to source a used motor with reasonable mileage on it and make the swap.

Oh, oh, oh!! I knew that answer. I bought a $200.00 car about 30 years ago that had that problem.

Thats unfortunate, but, such is life!
Thanks for taking the time to read this!
Time for me to go explore ebay.

And meanwhile, I'll just keep disassembling the engine.
I've rebuilt a few older motorcycle engines before, but only thanks to YouTube, forums and manuals. Haven't dealt with Vespas before.

Got the engine opened up - crankshaft seems to be toast - a lot of play sideways and not spinning free.
Not sure what I'm looking for with the bearings in both parts of the cases - no visible damage to "half-bushings" there.

Saw this on ebay:
https://www.ebay.com/itm/284903743486?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=ugnFe0z8Tde&sssrc=4429486&ssuid=heopizabsw6&var=&widget_ver=artemis&media=COPY

not sure if this engine will fit the 2008 lx150.
Also, not opposed to the idea of rebuilding the current one - already have the tools, manual and YouTube. But, swapping the whole engine will definitely save time.
Can anybody, please, share their thoughts on swapping LX150 2008 engine for 2001 Piaggio 160(??)
Thank you and sorry for being annoying.

It will fit. Seller doesn't know what he has. Not a 160, no such motor.

It's definitely a Leader 150, same motor as your 2008 LX, kickstart so earlier than 2009. Could be from Vespa ET, LX, LXV, S, or Piaggio Fly or Typhoon, all the same motors except Piaggio motors might be different final drive as they have 12" wheels.

If it's actually a 2001 would be ET Vespa, straight swap. Piaggio badged clutch cover is the wild card though, Vespa motor would have silver Vespa cover. Cover could have been swapped out though.

Worst case if final drive is different, it's a simple swap. Can pull the covers and count teeth to be sure.

Thank you so much for responding! Looks like it will be my route then!

Hi guys, thank you for responding here. So, bought an ET4 2001 150 motor, the scooter had the evap system removed by the previous owner, now that I am at the final (hopefully) stage of assembling - I have a question. This engine, unlike the previous LX150 2008, does not have this part (I assume a part of EVAP system?) circled in the picture:

So, the question is - where do I plug in the blue hose that people usually plug in to the T-connector(in the picture)?

Thank you
for your time!

the other end of that blue hose goes to the petcock attached to the fuel tank. It's a suction line that opens the petcock valve and allows fuel to flow from the tank to the carb. The suction from the engine intake via the intake manifold is what is generating the suction in the blue hose. Sometimes if you have a stuck petcock, it will flow fuel without needing suction, in which case the blue hose would be irrelevant.

The photo from ebay you linked to has the same intake manifold as your LX150. Or you can swap the intake manifold from your LX150.

Thank you for the response!
This vespa (originally LX150 2008 now with a 2001 ET4 engine) has a fuel pump too. Does that mean there is no need/nowhere to connect the blue hose into?

There is a fuel shut off valve in the petcock. The vacuum hose opens and closes that valve.

Roger!
Thank you so much!

That part is the vacuum valve for SAS secondary air system, emission control on later scoots. Not needed and often deleted along with EVAP.

gotcha!
Thank you so much for responding!

Sorry again, gents.
The petcock only has one connection - the fuel line.
Just started the bike - runs fine! But now the blue vacuum hose, attached to the manifold is just hanging loose… do I plug it? disconnect and put another vacuum cap on it? There is no way to connect it to the petcock. Or I'm even dumber than I thought I was.

put a vacuum cap on it and call it done.

you were on the right track. it's a later model LX so it uses a fuel pump.

Thank you!! Will do!

Here I go again, with more adventures:

So, the bike starts, runs - took it for a short ride around the neighborhood - didn't have a chance to accelerate past 30mph.

Idles rough. Carburetor was taken apart previously, meticulously cleaned (new to Vespas, but dealing with carburetors regularly). New intake manifold/gasket, new rubber hose from the airbox to the carb.
The fuel mixture screw is out 2.5 turns.
Compression is about 125-130psi.
Sprayed starting fluid around the hoses/carb - no changes, idle didn't pick up.
HOWEVER.. I can feel the air coming out of the carb somewhere when I put my hand next to it. And I can hear it too. Never dealt with it before.
Do you guys have any idea what it could be?

Thank you!

Common issue with the Keihin CV carb is when reassembling the slide diaphragm fails to seat in the groove correctly. Symptoms are slow acceleration and about 30 mph top speed.

Worth a try, pop the top of the carb off to check. Pretty much any time I had the carb apart had to redo it several times to get it right, helps to use a bit of grease to hold it in place.

Also compression might be low, iron sleeve, depending on how it was stored could have bore corrosion. Never tested mine stock but with the Malossi kit IIRC compression was 180.

Thank you!
The acceleration was definitely good - I just didn't have the road to go past 30mph.

Looked at the diaphragm- seated properly. Don't get where the air is pushing out - feels like it's coming right behind where the throttle cable attached to the carburetor.
Well, will be investigating more!

Thank you for responding!

The adventure continues. At this point, I understand that this thread is annoying, but, I'm venting, mostly so that I don't destroy the scooter with a hammer..

Since my last post, the bike stopped running. As mentioned above, took it for a short ride, decent acceleration, but idled rough. Got home, tried to play around with a fuel mixture screw - turned it 0.75 in (originally was at 2.5 turns out). The bike ran for a few seconds and died. Cannot start it for the life of me since that happened.
Here is what I've done so far to try and get it running:
1. Turned the screw 0.75 turns out (back to 2.5)
2. Took the carb out, took it apart, cleaned every jet and every orifice with a carb cleaner, brushes and compressed air again. Made sure the diaphragm is in a good state and is seated properly. Blew air through it - it moves as it should.
3. Reinstalled the carb, made sure all the rubber connections/boots/manifold are good - no cracks, good, tight connections (they are new).
4. Checked fuel lines (they are new), fuel pump engages when the key is in the "on" position.
5. Took the airfilter out, made sure it's not soaked in fuel.
6. Took the spark plug out - good spark. The plug was wet - I cycled the starter for 10-15 seconds a few times...
7. Sprayed starting fluid into an air intake (take apart, no filter) - nothing.
8. Battery's good, I also tried hooking it up to a jumpstarter - cranks good, but does not run.

I'm at a loss at this point. Super frustrating.

Sorry you haven't got it going yet!

How are the electrical side of things? Does the bike make good spark?

This bike is air cooled, right? It sounds like the air you feel around the throttle coils be expected from the cooling fan there. Are all the plastic shrouds in place to direct flow to the cylinder and head?

Yep, the bike makes a good spark!
Battery is good!
all the assembly's good.

It's almost like there's some electronic issue that just won't let it start.
(It's cranking, but not "catching on"..)

What's the immobilizer light doing? Does it blink and then turn off, as normal - or does it give some kind of trouble code?

Blinks once, then turns off. Normal.

Issue resolved.
What was done:
After taking off the carb, reassembling it 4 times, decided that it probably isn't the carb.
Went and got a new battery at Portland Vespa.
Looked at forums more and decided to try to start it without the air filter hose connected - and boom - it started and kept idling. As soon as the filter was attached - died.
So, started without the filter again, turned the mixture screw in 1 turn in (it is about 1.5 turns out). Bike idles good. Took it for a ride - all good - one issue - from the start, when I just start accelerating it sputters and almost feels like it's going to stall, but then picks up and goes fine. What can it be?

when you had the engine out, did you set the valve clearances? Important to do that.

Also, obviously need to get a new airfilter - try a Malossi red

Cold blooded engine? Need more warm up time? My 1700cc carb cruiser needs about 5 minutes before it's ready to rock. Or clogged air filter.

Air filter new. Black.
Valve clearances were checked too.

hmm. did you oil the new airfilter? If so, maybe you have too much oil in the filter.

will investigate more.
Just glad it runs

The LX carb has a little "acceleration pump" in it that gooses a bit of extra fuel when you twist the throttle. Sometimes these get gummed up. Look inside the carb and find a small black rubber bellows - that's the pump. The bellows eventually degrade and needs to be replaced; perhaps fragments of the bellows are interfering with the action of the acceleration pump. The bellows are inexpensively replaced with generic parts. I found mine on eBay for about $1, listed for a Harley - see the current listing below for reference, you may well be able to find a substitute more cheaply if this is the problem.

Looking for Carb Bellows Kit - 2007 LX 150
https://www.ebay.com/itm/284594909707

Accelerator pump or pilot jet.

When I was playing around with the Mikuni on mine which didn't have an accelerator pump had to go a bit rich on the pilot to eliminate off-idle stumble.

IIRC you can verify pump function by actuating the plunger with full float bowl and watch for the squirt.

Also again IIRC turning the screw out on the Keihin richens the mixture unlike most other carbs. Try the screw at 2 1/2 again.

If the pump is working and screw at 2 1/2 doesn't cure it maybe try a step up on the pilot to 38. This was a popular mod back when these were new. Scooterwest still has them.

https://www.scooterwest.com/keihin-idle-jet-idlejetlx-cm140101.html

Agreed, that is a cheap and easy mod. I did it on mine when I got it in late '18. It gives a little bit of extra grunt off the line. But I don't think it will fix this issue unless the stock idle jet is clogged.

The carb at this point has been cleaned a 100 times. All the jets are clean, the diaphragm seated properly, the accelerator pump works perfectly.
No air leaks anywhere.
Air filter was cleaned out and lightly oiled.
In addition to that, replaced a belt, clutch bell, variator today.

Fuel mixture screw is out 2.5
The moped rides well past 10mph - got to 50 no problem.
But, once again, from a dead stop, even when warm - almost cuts out during acceleration.
Played around with the screw - the bike dies when it's all the way in, but, regardless of what "out" position it is in - as soon as I start slowing accelerating - it's sputtering and trying to die on me.

Hmmm, perplexing. Does it run and rev normally on the center stand?

If so I wonder if the CVT is "sticking" in a high gear - even though you've replaced several components, for whatever reason the belt isn't getting all the way down as close to the crankshaft as it should be. So the engine is lugging at low speeds when it's loaded. It won't show this behavior unloaded on the center stand.

What happens when you go up a long, steep hill starting at high speed? This is the opposite, or complement perhaps, of the standing start that is giving you problems now. The transmission should downshift and keep you going at high RPM but lower speed. If the engine bogs this way it could be an indication that it can't get into a low gear ratio.

This drove me crazy on my buddy's Buddy because it felt so much like a carb problem and fuel starvation. It turned out to be corrosion and debris on the bushing (tube) that the variator is supposed to smoothly slide in and out on. It often, randomly, would bind in high gear and wouldn't slide out.

I suppose this could also happen if the variator had been assembled with a spacer washer missing, or out of order - the opposite of the so-called "Fuzzy washer" mod described here that for some models adds an additional or thicker spacer washer for extra pep off the line at low speed.

It that isn't the issue, can you definitively rule out the carb by temporarily swapping in a known working carb?

The bike does this when on center stand/unloaded… I try to throttle it and it lags.
No issues going uphill.
Assembled correctly - double checked.
Rechecked the valves too - up to specs.
Don't have a spare carburetor to check and a local store (Portland) doesn't do returns if I buy one and figure that that isn't the issue.

Will keep googling/trying

What you're describing seems to be an issue squarely in the range of the slow speed/idle jet.

For $8 you can replace it with an upgrade to a #38 jet as suggested above. But I am not positive that your engine uses the same Keihin carb and jet size that later versions do - that you'll need to confirm.

This is the jet for the Keihin carb, also available at ScooterWest for $11.
https://www.scooterworks.com/products/keihin-idle-jet?variant=46757982241048

Replaced the jet with #38.

So far - no luck. The scoot wouldn't start again - just cranks over and backfires every now and then.
All new lines, fuel pump works, carb's clean, all the rubber parts new, valves at specs, new battery, good spark, multiple new spark plugs.

Could it be a deeper issue? Timing? Piston? Decompression spring?

About to take the motor out and take the cylinder off just out of frustration:)