So I'm starting to get some things figured out with my new Chinese 150cc GY6 scooter. I was told when I bought it that the Speedo and Odo were in MPH but it turns out that was WAY wrong. They're both in KPH. (The owner's manual doesn't specify.) Now that I'm trying to ride the real speed limit I've found that the top speed is only 40 mph and the max revs at max speed is only 6000 rpm. The red line on the tach is 7500 rpm. Based on lots of well intentioned information on the web the engine may, or may not, be restricted. The variator may, or may not, be restricted.
The max rpm is only a concern if it is the cause of the low top speed of the scooter. Does it seem like the problem is that the 6000 rpm limit is likely causing the top speed to max out at 40 mph? Or is the engine revving about right and the variator is likely limited resulting in a VERY low top speed? Or is the carb slider likely restricted? And/or is the air intake likely restricted? And/or is the intake manifold restricted? I'm sure that the exhaust outlet is restricted. Not sure if the header pipe is restricted at the exhaust port but I can see that the output of the muffler is only about 1/2" in diameter. I don't think that is what is limiting the top speed but I guess it's possible.
The scooter only has 175 km (105 miles) on it. I was told to keep the speed below 45 mph until it has at least 500 km (300 miles) on it. If it won't go any faster than 40 mph that's not going to be a problem. But I NEED the $^*! thing to go at least 50 to ride in traffic. It is advertised as having a top speed of 55 mph+. The owner's manual claims a top speed of 85 kph (~52 mph).
I only weigh 140 lbs. I have saddle bags and a trunk on the scooter most of the time but the bags and cargo weight less than 10 lbs. So the weight shouldn't have any impact on the top speed.
I would wait until the scooter has more miles on it. That scooter is more than capable of higher speeds. If it still doesn't roll faster at 500+ miles then look into an intake or exhaust restriction. 150cc scooters aren't restricted, 50cc scooters are sometimes restricted to 30 mph.
1991 Honda Nighthawk 250-16,000 miles 1983 Kawasaki Spectre 750-43,125 miles 2009 CF Moto Fashion- 17,235 miles www.twowheeler.yolasite.com/
Sounds like you need a good card tuning , along with a good cvt tuning. At 140 lbs you should have no issue hitting 55+ mph . The roller weights in the variator could be too heavy , but at 140lbs id expect the weights would be way to heavy. If you have a long case you need to make sure you are running an 842 belt . The usually dont come stock with the longer belt . That makes a big difference.