Scootergrisen

but how does a 4 stroke scuter behave when it should have it's piston changed. I don't really want t spend too much money to guess what it has.

I'm not really sure, since i have only needed to do it once, when i forgot to change a gasghet and it dropped all of its oil, so it crashed and it was very clear that this piston wasn't going to move very easily. When i opened this, i saw that the piston had deep scratches on its side, so i changed both the cylinder and the piston to make sure that i wasn't using any damaged parts.

But to be absolutely sure that a piston is worn, you would have to do a cylinderleakage test, but those testers are quite expensive, so i think it would be best to buy some gasghets, take it apart and do visual inspections and inspect the piston rings clearance in the cylinder.

my biggest problem is adjusting those clearences that it mentions for the valves. Also, how much oil should this engine take?

Try on centerstand so backwheel is of the ground and accelerate to se if it can.
There is a oilpidstick with markings on. measure on level ground and on centerstand.
http://scootergrisen.org/scooterhjemmes ... e_olie.php

Adjusting the valves: http://scootergrisen.org/scooterhjemmes ... ntiler.php

Hi guys,
it's been a long last month I went to a local shop to buy a new piston and the guy there told me it was the sparking system.
I tried to change the battery, induction coil,cdi and spark plug. still works bad. I think it's the magneto.
if i don't start the lights it goes ok, if i start the lights it misfires. i think the coils of the magneto are shorted.
because of the snow for the past few days I left the scooter in the basement and now I can't start it anymore.

any advices?

Try using a multimeter to meassure different thing lik the batteri voltage both when the engine is nogt running and when its running and you gave a little throttle.
You can remove the generator coupler and meassure the ohm on the wires.

Write the numbers here.

actually I managed to figure it out. I have decent spark when lights are off, and crappy one when the lights are on. And after it took some salty snow which accelerated rust a little more, it doesn't want to start.

The extra ground cable I added was pretty thin, and probably was working in parralel with the old one, and now with the new rust, it stopped working at all. The thin cable couldn't take the current so because of this wouldn't start.

I looked at the rotor windings and they looked ok, from what I've seen through the stator holes.
I added a new thick temporary grounding cable and connected it to the screw from the fan case. after christmas I will try to redo the entire grounding wires properly and take care to use some military grade spray on insulation over it.

Thank you all for the help.
Your help was very useful.
My next plan is also to rebuild the carburator after properly cleaning it. I'm going to buy a repair kit from ebay.

People in here are really eager to show their abilities in english.
I'm pretty lousy so I'll keep my mouth shut. The only thing I can contribute with is that my G-buddy has no starting problems in idle-state from the garage . When the temperature's below zero as now, my scooter refuses to accelerate for a while and after that, things become normal. I'm now really much convinced that a oil-check can also make a difference in favor of a full synthetic motorcycle-oil.
I had this discussion with the wizzards here a while ago whether it's important. I didn't succeed to convince them - but the advise is hereby given.

OK, I did change the spark plug, too.