Modern Vespa

Hi all. So getting my 2002 et4 150cc back to running order. I had to let it sit for two years as I was away for work.

So far cleaned carbs and it starts perfect.

Some questions below:

So oil, it is ok if I use synthetic 10w 40 4 stroke? I'm in a warm climate area for the most part. I know manual says 5w 40 but I read some say it's a little too runny for the top.

Is it ok to use a motul engine flush before my oil change?

Oil filter. Having trouble finding a part number for this. Will the KN 183 fit? Amazon says no but their site says yes. Any other suggestions?

Gas wise I totally forget. I'm in America but I have to use 91 or higher correct? No 87 unleaded? Mid or premium?

Back rim wheel issue. Before I left I had gotten a new tire. I think the place messed up my rim because now I'm on the second tire and it deflates after a few days. Any tips or best to just get a new rim? Guessing they bent it somehow.

Any suggestions for a newer/lighter exhaust for my model? Again can't really find any options via a google search or here.

Also a refresher. My model is air cooled right?

Ty all again and sorry if these questions are out there, I really looked.

You can flush it if you want.

KN 183 is fine.

Fully synthetic 10W-40 is fine.

Fuel: 91 in the US. No point going higher.

Or HF 197.

Yes, air cooled. And you only have one carb. For exhaust, I have the Sito Plus and like it. Lighter weight than OEM, but not as loud as other options.

Motul engine flush? I use Motul in my 2 and 4 wheel vehicles but you're putting it in before an oil change, use something cheaper like STP or Seafoam. Remember the bottles you're likely to find are for vehicles that hold multiple quarts of oil.

Now for opinions on your comments not answered previously.

Back wheel issue: Inflate to correct pressure, use some dish soap with some water and spray or pour it on the valve stem - if it bubbles there's your leak.

If it is from the core of the stem, check your valve cap to see if it is the type that are slotted to tighten the valve core. If not, check your bicycle, some tube brands use the slotted style cap. If not, they're inexpensive and I make sure one if not both wheels on my bikes have a metal or plastic cap that will tighten/loosen the valve core. A four pack of these should be available at an auto parts store for less than a gallon of gas, or stop by a tire shop to see what options they have.

If it isn't a leaky stem, get your least favorite roasting pan, large enough for the tire and deep enough to submerge a portion of the tire (see the bad photochop below.) Get some help lifting the back of the scooter so the rear tire sits above the pan, then fill it with soapy water and watch for bubbles. Mark the tire with a sharpie so the tire shop can find the leak.

You'll have to look outside of the US for different exhaust - SIP maybe, but the age of the bike will limit availability, although there might be some sweet closeout sales. Don't hold your breath.

It is air cooled.

Thanks everyone.

My first time doing the soap test. But would this elude that the stem is bad and what is causing my rear tire to not hold air?

Thnx.

If it leaks from the valve stem, it is likely a bad core which is a 30 second job if you have a new core and a core wrench or slotted valve cap. The only other place likely for a valve stem leak is if it is cracked where it exits the rim. Then you need a new stem and that requires letting the air out and breaking down the bead. Possible to do it with the wheel on the bike but easier if the wheel is removed.

Thnx. Can I just replace the core and stem to be safe? Both at once.

Also I looked on Amazon. As well as scooter west.(out of stock) Can't locate them.

If you have a moment can you link me with what I need or let me know best place to purchase? Guessing I should try eBay as well.

Thnx and appreciate it.

Replace the valve stem. It comes with a new core. Every place that changes tires stocks them. It goes in from the back side so you need to break the bead on the tire. Search or ask for Schrader Valve.
I believe that the following will suffice.

https://www.amazon.com/Valve-Loc-Universal-Replacement-Heavy-Duty-Resistant/dp/B087QPTT54/ref=sr_1_4?keywords=schrader+valve&qid=1652997248&rnid=2941120011&s=automotive&sr=1-4

Ty so much. I really do appreciate it. So happy it's not the rim.

Based on my experience with replacing a valve stem , I would take the wheel to a motorcycle shop that has tire changing equipment and have them replace the stem. They'll have the right kind of stems in stock; I wouldn't bother ordering from Amazon.

Bringing in the wheel, off the scooter, saves a little money.

Motorcycle shops should have a tool that can insert a new stem without even breaking the bead on the tyre. At least, that's the case in the UK.

. Motorcycle shops here in the USA refuse doing any "small" job from April until October.

Maybe I'll try a car tire place in the interim.

We have these, and they are very easy to install. You can break the bead, drive the old stem out and stick one of these up there. They last as long as the regular one, but I call them emergency valve stems because you can replace them while the rim is on the bike, and it's very easy.

https://scooterpartsco.com/ricambi/misc/emergency-replacement-valve-stems

As far as everything else, the OEM filters are a bit cheaper than what I'm seeing for K and N on amazon, and Motul is very good oil. You probably don't need to flush the engine. As far as exhaust, Sitoplus is fine, I think tecnigas makes one too. It has to be specifically for Vespa models, otherwise the side of the body will bang against the exhaust when you hit a bump. You can use the exhaust for the injected LX and S models, but you need to get the plug that screws in where the sensor goes. Many exhausts come with the plug in the box, but if yours doesn't, you can find one easy enough.