Modern Vespa

I need some advice. My kit has arrived and in preparation for fitting the kit i have mounted the rings on the piston and installed one gudgeon clip on the timing chain side of the piston.

The bottom ring is the oil control ring and composed of three components a thin ring top and bottom of the slot and a waffle spring tension ring in the middle. My issue is that the ring is very tight in the slot and does not seem to squeeze down well to bore diameter. I refitted all the components making sure there was no overlap of the waffle ring.

The piston with all rings in place does go into the bore but is very tight. I can see that there is still a ring gap of about 1-2 mm as the bottom ring goes in but everything is very tight. So tight that it is quite an effort to move the piston within the bore. I did oil the bore and the piston and rings. Top two rings are fine.

Not sure if this is normal or if i should be worried?

Did you give the bore a good clean before oiling it? Sorry I can't remember how tight mine was when I fitted it.

Just a wipe around but actually tight to just get started in the bore. It seems like the ring assembly is not really fitting properly in the ring groove.

The three bottom rings should rotate easy in the slot before you put the cylinder on. It is a tight fit when you squeeze the rings and slide the cylinder over the piston.

Hi mikkels,
I have fitted literally scores of malossi kits in my time,i have never found one with a manufacturing defect, so i would point the finger at assembly error on your behalf.
Are the rings the right way up?
Are the rings fitted in the correct order?
Has the oil scraper ribbon overlaped ?
Did you clean the piston ring grooves with a craft knife or similar?
The piston is coated with a very fine silver film, if you rub it lightly with a scotch pad it will reveal the bright shiny alloy under it,
I would scrape the ring grooves (very gently ) with a craft knife then go over them with a scotch pad, malossi kits are made with very small tolerances to a very high precision.
I guarantee the kit will fit after this preparation is carried out.
ALWAYS ASSEMBLE USING PLENTY OF OIL
Cheers Andy

I have done plenty of 2 strokes but this is my first 4 stroke build at this level. The rings do rotate in the bottom ring groove. Not as freely as the individual rings rotate in the top two grooves.

I wonder if I lift the ring components from the bottom groove and clean and closely inspect the groove before reassembly.

Hi Andy. Don't worry I'm blaming myself not the kit. The rings that make up the oil control ring are symmetrical and do not have a top or bottom. The ribbon has not overlapped as I checked that very carefully. I am thinking that the issue is the ring groove is slightly dirty or has some swarf in it so I will follow your advice and clean thoroughly. Don

Check the groove as andythebuilder suggested. If everything checks out , it is a rather tight fit when you push the cylinder over those rings.