Gy6 is sluggish, By bugguy (Read 2,714 times)

[bugguy]

so about a week ago i resurrected a scooter from out behind the shop so that my girlfriend could ride it to work.
it was sitting for over a year and not running so i drained the tank checked the filter petcock and vacuum line to it.
carb was leaking fuel so i replaced it and the bike still would not start. checked the air box replaced the cdi still nothing. replaced the plug wire and coil and it fired right up. after adjusting the valves i put the body back on the scooter but after a test ride realized that it was very sluggish. pulled the plug and it was smoked. after trying to adjust the air fuel mix with the adjustment screw to no avail i removed the jets from the old carb cleaned them and put them in the new carb. the new carb had larger jets in it and was flooding even at the leanest settings. with the new jets in the carb responded to the mixture screw and i set it to highest idle then backed off the idle screw to disengage the clutch. another test drive was better no more smoked plug but the acceleration and hill climb was horrible. 15mph max on a slight incline. what should i do next?!?!?! I have swapped the cdi box with one off another 50cc and taken the other scooter out and it has a tremendous amount more power. could this be a cvt issue?

[Bashan]

Could be CVT after sitting that long. Plant your feet and give it some throttle. Will the engine rev without the bike taking off? Also, check your compression.

[bugguy]

No it will not rev without taking off And I did check the compression when I had it all apart but I don't recall what it was. I will pull it apart and check again. What range should I be looking for

[Guitarman]

Well, when Rich or Alley forget their meds, then they get sluggish. So, check the gas and the tank. Make sure it's not blocked with crud.

[Alleyoop]

If and when you check the compression, min is 120psi for the motor to have descent power if less the motor is not making enough power to pull the weight.
Alleyoop

[bugguy]

Well I pulled the body back off today and did a compretion test but only found about 100psi and while I was in there found a vacuumed hose was disconnected from the air box side of the intake. It runs much better now but still not quite what i think it should do. The tank is good I flushed it all out when I first dug the scooter out. If compretion is the final answer what would you guys suggest. New head and ring? Should I get a big bore kit while I'm at it ? I have the 85 jet that was in the new carb when I got it would that do if I punched it up to 80-100 cc.

[Alleyoop]

When you checked the compression did you hold the throttle wide open? You have to hold the throttle wide open so it sucks in as much air as possible otherwise you will get a low reading. But if you did it right then 100psi is very low. And since you will have to tear the top end might as well go for a little more displacement.
Alleyoop

[bugguy]

Ok thanks for the input. Any suggestions as to a big bore kit ? Brand, size ,vendor. I'm not looking to sink huge money in to it but I don't want to have it fail in a months time. 

[Bashan]

TVnACman has a nice 100cc upgrade. I've bought from John and he's very good. You might call Matt he's very good also.