hi, just need a second opinion to confirm my supspisions, ive gota 172 a/c engine.its not in a frame and i havnt had it running.i put a second hand 172 kit on it.no scores on the bore but piston bit scuffed up.engines wired to a loom but cant get it started..has spark and fuel..i bought a compression tester and comes up around the 75psi mark. i then tryed my 50cc and it has 100psi. im not sure of what theyre meant to be but i heard around the 150psi mark. would i be safe in assuming this is why it wont start?? if anyone can help that would be great! and also, i suspect im gonna need a new piston kit, but i cant find the size indicater on the bore..anyone know where it is on the a/c 172 bore?? Thanks in advance! :good:
the top of the piston should say its size +0.5 +1.0 +1.5 etc You state the piston is scored but dont say if the rings have been changed compression on a 50 should be around 110, anything less and it needs attention...be it a re-ring and hone or rebore/replate
its the 172 engine that wont work. the 50 is fine,just wanted to know the compression to compare. wat compression should 172 be,mines 75psi,i bought the 172 kit second hand so dno wen rings wer done.and wud 75psi be too low to srart engine? thanks
you bought a used kit get new piston and rings on there its better to be safe then sorry. why do you think the kit has been removed it obvious the rings are chuffed and you say the pistons marked too. dont bodge your bike fitting parts that have damage especially moveing parts ffs
yeah i see.im gonna order one tommorow.pistons scuffed and on the top has loads of dents on it,dnt know how.im new to scooters.i placed the rings in the bore and you can see gaps around it so thats where the compressions gone. regading pistons,is it better to get a genuine malossi one or the pm tuning one? thanks again for your help
ok, ive ordered a new piston kit along with bearings.piston and rings are buggered.. problem is now, ive split the cases, but i cant get the crank out of the variator side. its stuck in there good. any ideas??
heat up around it and wind a nut on the end of the crank and hit it with a copper mallet (or hammer if you dont mind damageing the crank) and it should pop out make sure you heat it up well with a hot air gun
