Modern Vespa

You video looks like an embedded image of a video and can be clicked on. You definitely want to get the carb cleaned out no matter what. I would also remove the petcock and drain the gas and make sure to put an inline filter in the fuel line too or you may just be re-doing that carb again in a couple mins of trying to start it! At least this has been my experience. YMMV

When getting these back on the road after sitting I have been:
Replacing petcock (helps to drain tank quickly and flush particles out)
Replacing Battery
Replacing all Fuel lines and adding inline filter (use clamps at all locations!)
Dismantle and clean carb (remove jets and clean them on bench)
Flush brake line
Replace engine oil
Replace hub oil
Replace air filter
Replace clock battery (I like to have a functioning clock)
Replace spark Plug
Replace CDI/Coil w/unrestricted version

I removed it and applied 12 volts from two batteries and it doesn't react at all. It wasn't too hard to remove but putting a replacement back in is going to be a bear because there is this tiny screw holding on the positive lead and I think it will have to go on last.

I just pulled the carb and its a Keihin AE2BYAR. Is this the type of "cheap carb off the internet" you speak of? It's not what come on the scooter, right? I'm trying to decide whether to try to clean and rehab or replace with OEM. Thanks!

Greetings:

If it is genuine Keihin, it isn't a "cheap carb" and more than likely is the original carb. Vespa used Walbro (actually another now-Japanese brand) up until 2005 or so, and since then Keihin until fuel injection took over. The Keihin is worth cleaning and keeping, but it does require near-complete dismantling and thoroughness, especially the tiny enrichener and pilot circuits. Wiki has the How-Tos.

OK, thanks - that's good to know. I'll try to use it. I pulled the bowl off and it was pretty dirty in the bottom. The pilot jet is completely plugged, and I can't clear it so I need to find a new one. I'm going to try just doing that before taking the whole thing apart, but know I might need to still do that later.

Good that you are getting around to this. Your carb looks legit unless someone played around with the electric choke. That is what the OEM looks like. Use some magnification if you need it but write down someplace what jets you have in the carb. There is a number stamped on them. I think OEM for your scooter should be.

Pilot Jet .035
Main Jet #75

Greetings:

If you just want to clean the jets, find a small glass or plastic container. Spray out an ounce of carb cleaner and drop the jets in for a day or two. You must cover the container or all will be gone by morning. You will eventually be able to clean the pilot. Use a bristle from a brass brush to poke into the little holes after the jet soaks for 48 hours. The larger hole in the main jet usually self cleans with this method, but push out the emulsion tube and address the little side holes in the cylinder. Keep track of orientation of all these little brass parts.

Pull the float needle and dress the bore and seat with a partially-stripped Q-Tip with some Colgate toothpaste on it. This should leave the seat both clean and minty-fresh. The needle tips do tend to get brittle and you might need a replacement. Don't be shocked at the price!

If you do the whole carb:
A can of Carb Cleaner - Berryman's comes in gallon size with a dip basket in the can. You can soak the whole carb body in the stuff once the float and diaphragm are removed. It takes patience, but the Keihin is worth the effort.

This is good info. I have not soaked a carb but I have seen those gallon kits. I am assuming you remove the gaskets yeah?

Also I wanted to mention that those Chinese Keihins carbs for 22 bucks (and free shipping with Amazon) are great for repair parts. The OEM Keihin needed a special tool to adjust the air/mix screw but the knock offs come with a nice one that has a flat screwdriver adjustment! (two turns out to start) plus new gaskets all around! and a new float if you need it. The ones I have received all have a #78 main jet installed too so if you want to upjet for a cylinder kit at a later time you got it. I used the 035 pilot from a couple too so I didnt have to clean the old jet.

Greetings:

Yes, all non-metal parts should be removed from the carb body before a refreshing Berryman's dip.

Free gaskets are great. Check and compare the floats, particularly the adjustment tab. It is not guaranteed that the Chinese float needle will perform correctly in the Keihin body. Same goes for the main and particularly the pilot jets. Compare contour and length and tip configurations. Eyeball the side holes in the pilot. I have experienced poor performance from Asian knock-off jets that purport to be a specific size, but do not perform that way.

Gauge the main jet for "78" if you have indexing bits. You may find the Nominal size is not the True size.

The 'D' screw is/was only for the North America market. ROW - ordinary flat-bladed screwdriver. Easy enough to make a tool for it from some brass or copper tube.

Thanks for all the tips on getting the jet cleared. Apparently heat also helps. I need to order a starter anyway, however, so I'll just order a new jet at the same time. I think Motovista's shop (Scooterpartsco) has both. Maybe I'll get one of those D-shaped tools for adjusting the mixture too.

I have the D shaped bit on the end of a Flexi screw driver. You slip it through the vents on the lower plastics below the fender and it does the trick. I also marked it with a sharp where the straight part of the D is so I can get it on the screw easier, it also helps in counting turns.

D-shaped adjuster came on the original carb for my '07. I bought a brand new Piaggio one (also Keihin) from Scooterpartsco and it uses a flat blade adjuster.

I just wanted to report that I installed a new starter and a new jet in the carb and it starts and runs now. Yay! Thanks for all the help. Now we can tick through all the other things that should be done to a scooter that's been sitting for a long time.