People 250 is slow

[tidefan662]

Hey everyone! I'm new here! :-)
I own a 2006 People 250 with roughly 6000 miles on it. I bought it used from a friend who stored it last winter without stabilizing the fuel. When I bought it, I ran some fresh gas/Seafoam through it to blow out the cobwebs. The scooter idles smoothly, and has very good acceleration, but it flattens out around 50-52mph, indicated on flat ground and no wind. I can get it up to 55-57mph if the wind is favorable, on a down grade. 
I have changed the spark plug, adjusted valves to spec, changed drive belt and weight rollers (OEM parts), all to no avail. I also checked tire pressure, changed engine and gear oils, and the hoses around carburetor look good. The throttle cable opens all the way (looking at the carb itself to make sure).
A couple of curious things: 1. the engine revs up smoothly to a point (RPM's max out at 2/3 throttle) and 2. The drive belt rides up the variator pulley as it should, but not not quite all the way. Conversely, the driven pulley does not throw all the way out at max RPM... is it supposed to?
I'm 6'1" tall, about 250lbs... I've wondered if my P250 is "giving it all she's got!" - and accept it for what it is - or should I keep putting time and $ into it... 
Any help or insight will be most appreciated! 

[SCOOTER 2290]

I'm not sure about other scooters. But mine is a s250 2009 and it really does go 70 all the time into a lite wind. And most of the time 75. I like hwy driving... the speedo says 88 to 90...I know its at least 80 miles per hour...went to s. dakota and back from wis. was impressed, so I think some thing minor is wrong. Throttle adjustment or carb is still plugged a little. Sea form maybe or a shop... good luck and do not give up.. fantastic machine. Am 60 and have rode cycles all my life since 12. this really is a great machine.

[Punk052]

check your diaphram on the carb, if there is a hole in it the scooter hits a wall around 50-55

[kymcoallan]

It should at least be able to run 85 mph it is my easy.

[mrbios]

The main jet and probably the slow jet are clogged Seafoam won't do anything and this problem didn't just come about from sitting over one winter it takes more than that for real clogging;  at least a year or more.

[Restrictor Plate]

It's important here when speeds are mentioned to keep in mind that there is a big difference between indicated (on the speedometer) and actual (from a GPS.)

I have a 2005 People 250. It has 36,xxx km on it now. I bought it new. I have records on it from when it was new and I did a speedometer comparison check on it. At the time I got a top end of 83 mph indicated, and 73 mph actual (GPS).

Recently I was losing top speed. It was time to do a belt change and I did, but that did not improve the speed. It had dropped down to 61 mph gps maximum. Took it into a shop, where they found a wet and oily air filter (a result of the other problems), a few vacuum leaks, and gunked-up carburetor jets. After cleaning the carb, I road tested it again and was getting 73/74 mph (GPS) cruising both directions on the interstate. I was happy to be back to my original top speed with the bike.