1 piston ring????

[Airhorn]

So i was talking to a 2 stroke guy about my l380. He mentioned that a trick oldtimers use on old 2 strokes like mine, is using only 1 piston ring. Has anybody else done this?? it seems like there would be less compression, but the resistance from the missing ring might make up for this.

[smudvapor]

So i was talking to a 2 stroke guy about my l380. He mentioned that a trick oldtimers use on old 2 strokes like mine, is using only 1 piston ring. Has anybody else done this?? it seems like there would be less compression, but the resistance from the missing ring might make up for this.

I have heard the same thing but I have never been brave enough to try it.

[Airhorn]

lol. I wouldn't have even thought of it if i hadn't busted one of my new ones. tightened the compressor, and "pop". couldn't get the other one in there either. And yes, im putting it in the right way up...... Kinda frustrating. Wrong size?????? i bought engine specific rings and its stock piston.

[smudvapor]

lol. I wouldn't have even thought of it if i hadn't busted one of my new ones. tightened the compressor, and "pop". couldn't get the other one in there either. And yes, im putting it in the right way up...... Kinda frustrating. Wrong size?????? i bought engine specific rings and its stock piston.

There is a small pin in the groove on the piston that keeps the rings aligned in the piston. If you don't have the ends of the rings lined up correctly you will break the rings when you compress them because the rings will get pinned on the pins. Look very closely in the grooves on the piston and you will see the pins. There is one pin in each groove.

[Don]

A lot of the performance pistons use only one ring. From what I understand it's to reduce drag. I know some of the old racers would leave the bottom ring off a conventional piston for the same reason. I'm not convinced that it's worth the small amount of performance you gain in exchange for engine life. There should be a spec for ring end gap, usually .008" to .012" or so. If the gap is too small, the engine won't last ( speaking from personal experience).

[racerone3]

Racing Karts as a kid, we would do that with a briggs. made great power but not for long. also smoked like crazy till they got up to temp

[Airhorn]

There is a small pin in the groove on the piston that keeps the rings aligned in the piston. If you don't have the ends of the rings lined up correctly you will break the rings when you compress them because the rings will get pinned on the pins. Look very closely in the grooves on the piston and you will see the pins. There is one pin in each groove.

Yeah. i saw that. i had the pin in the middle of the gap. The ring has a side gap. Thats why im confused. The ring will go in part way(it's a half keystone ring so its beveled on the top) but won't fully compress. are they supposed to be really hard to press in? I'll probably buy 2 more rings and just install what they had stock. would be fun to dyno the 2 stroke and see the difference between 1&2 rings.

[james gerber]

As much as it may fit, I don't to want admit i'm an old timer. Running single ring pistons here (G-50b, for racing) They work great, but they still get hot and the power drops off.
Some (old time motors) used three rings, worked good also, lasts longer, good low end torque, little lower on the rev's though.

[Airhorn]

ok. cool! that helps. wasn't saying your old, just experienced.

[Airhorn]

ok. this is sad. I wasn't even getting close to getting the rings to fit. I measured the rings and the slots in the piston ect. By the looks of it, the ring fits an L340 piston. not L380. Got new rings on order. Im gonna do 2 rings just to be safe. I want this to last.