Just wanted to relate my experiences:
We bought a People 50 last summer from a dealer. He had it as a trade in but had originally sold it new in 2006. Less than 600km on it at the time. In hot weather it only needed a little while to warm up but the choke circuit didn't really seem to work correctly. When we would try to accelerate it would just bog down and sometimes die - until it was warmed up. It also had slow throttle response going down the road, but always ran strong. The colder the weather got the worse the problems got, so the other day I decided to see what I could do.
With the help of info on these forums and other info online I started to go try to find the problem (it sounds like lots of people have had similar problems, unfortunately). After removing enough covers to find the engine, I checked the resistance on the choke mechanism (that for some reason is called the "automatic bystarter" or some such thing.) It checked about 4 ohms which is good I guess. I tried to check and see if it was getting voltage and (after quite a while) realized that it has to be checked using AC voltage settings on your mulitmeter (another mystery, I must admit). It checked right at 12 volts AC.
My next test was compression. It cranked right up to at least 120 psi, probably more, so I knew that was good.
The coil was next. Checking the resistance between the + and - (the blade connectors on the coil) is supposed to be 0.15 to 0.18 Ohms and it was. The resistance between the blade connectors and the spark plug wire is supposed to be up to 10.2kOhms and I checked closer to 14 but it doesn't seem to be a problem.
On to the Keihin carb. I had to figure out which adjusting screw was what, and found that there are three screws of concern: two at the top and one at the bottom. The bottom screw is a drain and makes no adjustment - just drains out the bowl. The top two are where the adjusting is done. The right one (it's in line with the throttle cable because it adjusts the throttle) is the idle speed screw, or throttle stop screw, if you prefer that nomenclature. All it does is adjust the idle speed just like the twist grip on the handlebar does. The idle's supposed to be set at 2000RPM which seems fast but this is a 2-stroke so I guess that's normal. My clip on tach would not read for whatever reason (AC vs. DC again?) so I just had to go by feel on that. The left screw is the mixture? air bleed? whatever you want to call it. It should be adjusted to the highest idle possible. Mine started at about 1.5 turns out, and that's where it's at now. The stop screw is at about 2 turns out on mine. In theory, you should adjust the left screw for the highest idle, and then adjust the right screw for 2000 RPM. I could not get this thing to act right no matter what I tried. It was horribly unpredictable and if it had cooled off (I'm working outside and it's about 50 degrees) the choke would kick in and it would race for a while, then die. I concluded that some fuel or air circuit inside the carb had to be clogged or something.
So off comes the carb. Didn't see anything inside that looked like a culprit but I stripped it and soaked the main pieces in carb cleaner.
Note: I'm blowing the thing out and feel something hit my foot. I'm standing in a gravel driveway so I'm thinking "this ain't good!" I look and find a little insert piece that I finally determine goes in ahead of the the main jet. It guides the throttle needle I guess. So just watch for that if you're doing a similar job.
My main jet is marked "70" and the secondary? is marked "35". I read lots of stuff on here about drilling out the jets or using a torch tip cleaner to ream them out. Not sure if I want to go that route cuz it seems like the thing ought to run as manufactured, shouldn't it? But I do have a set of small number drills (60-80) so I did check the main jet for size. Coincidentally, the #70 drill bit was a little tight in it so, I guess I just couldn't help myself, I grabbed the next larger bit (#69) and worked it through there with a small drill chuck.
Reassembled the whole thing and after getting the fuel back into it, it fired right up! Halleleuia!! It runs good too! The choke works for about 2 minutes during which time you can take right off, and when it idles down it still pulls without any hesitation at all. I haven't tried it on the road yet but around the yard it's great. I tested it again today after it was completely cooled down and it worked flawlessly.
Oh, I didn't mention that before I pulled the carb I ran some SeaFoam through it by squirting some into the venturi and I also added some to the gas.
I can't pinpoint the exact cause of my problems but the sum total of my efforts resulted in a correctly operating scooter!
Hope this helps anyone who has similar problems before they go throwing money at it. The total cost of my repair was $0.00. I was so pleased I even waxed the thing before I took it out of the shop!
Thanks for reading all this!
