new to scooters - need help

[McNutts]

Howdy. I just bought a taotao evo 150. it's used with about 1200km on it. it runs and the previous owner turned up the throttle screw since he was a big guy. I rode it around for a test run. it wouldn't go above 40mph and the RPMs never went above 5000,that was right at take-up then quickly settled for 4500 RPM. I adjusted the throttle screw back down but the only thing that changed was it wouldn't try to drive itself at idle. I don't know where to begin to try to figure out why it is so slow/low RPMs. Any advice would be super. you might need to dumb it down for me as I don't know squat about the proper names for stuff.

[rks]

Will the rpm's climb to normal level with the scoot on the center stand? Did previous owner tell you about any modifications he made?

[McNutts]

What would a normal level? when I started it, while on the center stand, I opened the throttle all the way and it went to 5k then immediately decided it didn't like it and bugged down to 3k. I then let off the throttle and slowly opened it to full. it went to 5k then decreased to about 4.5k It seems to not like getting gas at all and kind of stutters while maintaining that rpm.
He said the only thing he did was adjust the throttle screw so it pulled higher RPMs. when I set it back I didn't notice any change in RPM.

[McNutts]

good lord, I check the oil and it didn't even register on the dip stick.

[McNutts]

false alarm. I don't know where it went but when I check, the dip stick was bone dry. I checked again prior to draining it and checking the filter and it was about half full and as black as midnight. just changing the oil produced a higher RPM when resting on the center stand, like 6k without gunning it. however, taking it for a ride around the block didn't produce any real results. still sucked going up a hill, topped out at 30pmh. going down the hill I got it up to 45 but went back to 40 when it leveled off. still won't go past 5k RPM. seems like a fuel problem with it bogging down and such. the air filter looks brand new. not sure where to start on the whole fuel thing other than spark plug but it looked ok to me.

[kz1000st]

Check your vacuum lines. If one is off or cracked the engine will run very lean and have no power. Also check and see if the fuel lines have any kinks. Have the valves been adjusted yet? It's getting into the mileage where they need their clearances checked.

[McNutts]

I'm going to assume that the valves have not been checked/adjusted. The guy hadn't even changed the oil. is there a how to on the clearances somewhere?

[rks]

You might type "scooter pdi" into your favorite search engine, and read up on the subject. I would almost guaranty one was never preformed on your scooter, if it had been you wouldn't be having this type of problem at 750 miles....So, read up on the subject...you will learn a lot....then spend a day doing it.....afterwards, you and your scoot will be a lot happier.

[kz1000st]

Valve clearance should be set to .004 inch on the intake, .005 on the exhaust for a 150cc scoot.

https://www.youtube.com/watch?v=s0K-ytyjOFg

[McNutts]

Thank you so much! I bought a feeler gauge and some carb cleaner. I will have to do the full PDI this weekend when I have more time to dedicate to the job. for tonight I'll be checking what lines I can see, the fuel filter, and valve gaps.

[McNutts]

so, I checked the valves and couldn't even get a .002 gauge in it so adjusted it to .004. While putting everything back together, I noticed a huge rip(as is only being hold together by about an inch) in the duct coming from the air filter. since my ex has to drive it to work in the morning I applied liberal amounts of duct tape until I can get a new one ordered. after getting everything back together I took it for a ride. It ran smoother and was able to get it to almost 50 mph and about 6k rpm. still not able to get consistent results with WOT but it is improving. heck, even the take-off speed was greatly improved. So I'm not sure if it was the broken air hose or the valve adjustments but I'm just happy that it is safer to keep up in traffic.

[kz1000st]

Good news. I would put some Seafoam fuel system cleaner in the gas tank and be patient. These GY6 engines don't really come into their own sometimes until after 1,000 miles. Your 1200 km. translates to around 750 miles so the engine could still be snug. 50 mph is pretty good for now and replacing the air hose plus a few other details you may discover may give you a little more speed.

Glad we could help.

[McNutts]

I have searched high and low for this stupid duct. it looks like this one (http://www.motoparts-superstore.com/air-filter-assy-for-jonway-yy150t-12-125cc-150cc-atv-go-kark-scooter.html) (of which there are tons all over the interwebs) except on mine there is a port at the top of the curve for a smaller line going to something else. the smaller line has an arrow shaped fitting to go in it. I'm wondering if it would be ok to get the one in the link and just cut a hole in it and shove the smaller tube fitting in it.