Malossi pistons trapping rings

Hello All,

I have had a problem with the 2nd malossi big bore kit (70cc speedshite) Both times the failure has been the rings getting trapped in grooves thus leading to piston just slapping around in bore. Do malossi not provide these kits with correct ring clearance? If not then does anyone have any info on correct clearances etc so I can modify new piston correctly.

Any help much appreciated :mrgreen:

Colin (full time kids scooter mechanic LOL)

 

its gotta be the way your putting them in surely ?

this a 2 ringer i take it?
are you puttign them the right way up?

 

There is the same chamfer both top and bottom of ring so it doesn't matter which way up they go. I was trained as a motor mechanic many years ago so not totally unfamiliar with such things, however can't help thinking I have missed something daft. usually goes after around 2-3 months riding around 20 miles a day. I have the mixture a little on the rich side to stop him melting pistons and the head is a little coked up when removed but nothing major. It does look to me like the ring clearances aren't correct and temp change is trapping them.

Hopefull in finding a resolution :beg:

 

OK that will teach me for not inspecting engine properly. Small end has loads of play and on closer inspection badly worn con-rod journal. Can see the lines where bearings have sat and worn into :bye:
So better look around for new crank setup or something and bearing kit. will then rebuild engine and hope to see end to problems.

Cheers

Colin

 

Thanks mate much appreciated :mrgreen: Might be just as easy to pick up another engine once i get into replacing crank bearings, con rod, gaskets etc. Then again would only have another engine of which i know nothing of condition so may be starting all over again cratch: