Help.......please

[fokey]

I bought a 2012 MotoBravo GTX 150cc with a GY6 motor from a lady who said it needed a new coil. Well long story short is that this lady flat out lied to me! Almost every vacuum hose was either missing or cut. Parts are broken and missing. Bolts are snapped off in plenty of locations. I checked for spark and plenty of good spark so the coil issues is not that problem. I then checked compression, well the needle would maybe bounce to 30lbs and drop when I stopped cranking. I pulled the motor and tore the top half apart. Basically looked beaten, and the oil was like sludge. Probably never changed the oil. I bought a rebuild kit for it. Came with new keg, piston, rings, gaskets, the usual. Cranked it over and the needle on the compression tester didn't even budge. Pulled it apart and held the head to a halogen lamp and can see light through the seated intake valve. That's probably why I have no compression. Tried different combinations of old parts with the new parts and can only get the needle to bounce around 30lbs when I'm cranking it then it drops. I don't have the carb or exhaust hooked up when I'm testing compression........don't know if that could be a problem or not. I want to try what I can before I toss it in the garbage

[blueboy5000]

No you should not see light through a seated valve, adjust your valves to .004"

[blueboy5000]

Having the exhaust and carb removed shouldn't interfere with compression.

[fokey]

I could see light through the seated valve with just the head in my hands. It wasn't connected to the cam or rocker arms. Just the head, valves, and springs were in place.

[blueboy5000]

That's the problem then. That's not the first head I've seen that needs "lapidary".


Pick up a valve lapping kit and lap the valves.

[fokey]

I got my scooter running but it won't start when cold with out spraying starting fluid into the carb and holding it wide open. Once it's warmed up it'll pop off no problem. I do not have an air box for it since I bought it and it didn't have one. Also, i'm not sure I have all the vacuum lines hooked up correctly. There is a place where a vacuum line should go located on the head but it blows air out of it when running. I've heard these Chinese scooters can be picky if all the lines aren't hooked up correctly. I'm gonna buy an air box for it once I figure out which one it needs. Any diagrams would help out alot.

[rks]

If you don't have an air box, what do you have? A lot of us have removed the air box in favor of a free flow filter. Here is mine:

http://scootdawg.net/album.php?albumid=92&pictureid=551

When this is done, the carb needs to be rejetted, more air means it needs more fuel, or it will run way to lean, which in turn means to hot.

Running your scoot with no air filter what so ever, will cause an extremely lean condition, and hard starting, not to mention that sucking in unfiltered air, will destroy your engine.

You need to spend some time educating yourself on the gy6 engine. There are videos on youtube, covering everything you'd ever want to know about these engines.

[fokey]

I've been trying to educate myself on these gy6 engines. I'm just piecing this thing back together from the condition I got it in. I do have a couple of those K&N filters for it and I will tube them just like you did in your picture. Thank you for your help on this matter.