New Airsal piston in Airsal Sport 50 cc cylinder, Fever ZX -02

[marlon69]

Hi everyone! I'm new here.

Bought a Kymco Fever zx -02 really cheap but the piston was crap so I ordered a new one from the same company.
I started the scooter and it ran nicely for a minute or two then this:



The crankshaft isn't loose. I did put the black piston ring above the silver one which is wrong but it wouldn't make this rattling noise now would it? Is it bad compression? Base gasket problem? I need ideas? Anyone got one?
 

[thebatman]

welcome to the forum marlon69...i tried to look at your vid but i use my cell phone here and for some reason it woundnt show that one. anyway, yeah you need to get the rings in right. itll help alot.   you should clean the cyl again also when reinstalling. have you checked your oil pump for proper operation?. throw some pre mix in the tank just for safety. the rings were an issue but if no oil was getting in there to cause your seize. the rattle COULD be the crank bearrings, but you said it wasnt loose. according to the manual, your only allowed 1mm either direction. what sort of rattle? ungodly rattle, going to fall apart sound? .  a rattle or knock/ping sound?...dam phone. did you just install the kit?. why only a 50cc kit,btw?....

[marlon69]

If you have a smartphone you might have to get the YouTube App.

How do I check the oilpump?

The rattling sound was like a tractor or like some metal part was loose.

Would the rings make that much difference? If so the previous owner had them on the wrong way too. Someone at the shop where I bought the piston wondered if I had put it on the correct way and I only put it like the previos piston. The other way around would put the ring gaps right at the exhaust outlet and that don't sound right.

I bought the Scooter with the Airsal cylinder 50 cc sport already there so since the old piston was bad I just got a new one to be able to try the darn thing b4 I got started on any mods.

[thebatman]

look at the cable that goes to the oil pump. make sure the arrow is in between the 2 notches. you are allowed 1mm there also. check the oil line to make sure still hooked up.not much to the pumps, some ppl just remove it completely.....dude, it is sounding like your bearrings. i would redo the rings, clean that up, reinstall.. check the play of the crank. remove the cvt cover, lossen the belt or take the outer drive off, check the play up, down and in, out... i would also put some premix in the gas tank, better safe than sorry....mine has rattled before at a red light(b4 i started modding). i thought the WHOLE BOTTOM would have blown out but it stopped when i had gotten to the next light..a bearring wont stop im sure..

[marlon69]

It seems like the answer might be that I have put the exchange piston and rings the wrong way. It's a shame that Airsal stopped putting some mark on top of the
piston. I put it in the same way as the old one not knowing that the previous owner had done it wrong!
the flowport needs of course to be placed at the intake!