Three ring piston
- Thread starter Goat Herder
- Start date
Please elaborate. What's the benefit?I just scored a three ring piston . anybody have stock chinas with three rings in them?
In our conversations, Brendan said "If they want to gain some top-end, have them remove the botom ring". I had to remind him we are talking about bicycles. He's ridden each of the bikes I've built and he always gets a kick out of them.
"EDIT"...Just wondering where you found a 3-ring piston and what was the, application, reason for it?
Jim
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I seized my first 80cc engine from Kings Motor Bikes,Motorized Bicycle,Bicycle Engine Kit,Bicycle motors,Whizzer motorized bicycle because the idle screw came off. Got another upper cyclinder kit (from kingsmotorbike) that includes the cyclinder head, piston with three rings, the piston rings, and the head gasket. I only put on the top two piston rings on and left the bottom alone...and the motor is running like a monster with lots of torque and power. I think the engines from kmb are made well. I haven't tried the other companies yet. As far as the application, I don't know.
I have never seen a two stroke with three rings, even my motorcycles had only two rings, now my four strokes had three rings, the bottom ring being a different kind of ring that would clean the oil of the cylinder wall on the down stroke. I would think you would lose some compression by using only one ring in these engines since the engines I have seen the rings dont fit snug up to locating pins.
I speculate that one can get more compression after shaving the head . Yet three rings is better compression . I shall have great mid range torch , with a 40 tooth rear sprocket living next to the mountains its perfect. I have done all the simple mandatory modes that these chinas need. More compression to me is a plus I don't need to go much faster than 27 mph.I simply want torque I'm making a two smoke run with the torque of a four strock.
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Hey more torque with a three ring piston. I am tempted to put that third piston ring but 80cc runs well now. Just got my new cns carb still figuring out how to install it. I think I'll be able to break the 50+...see "high performance tips.....how fast can your 2 stroke go?"
A standard speed trick for years and years....decades- has been removing a ring. What is possibly lost in compression is more than made up with less friction. Of course, usually the ring (or rings) left are run with smaller end gaps.
Yea we used to do that on motocross bikes, get the next oversized rings, and grind them so that there was very little gap at the ends where the meet.........
Some mopeds, like many classic Zündapp models, has only one ring as stock. I was fascinated by that as a kid, thinking it might lose compression.
Some time back when I was researching those Russian motors Grubee had I found some info from the USSR where the guys there were explaining that they leff the bottom (of 3) ring out. They said you simply didn't need it.
The cylinder on that one was with a steel liner and were prone to seizure. Yet they said if one allowed the motor to cool for a few minutes that it would restart and run just fine. They stated the piston used in those motors were tapered to the top from the bottom where as the bottom of the piston was
barely wider than the top.
Their motors seemed to be dependable by and large with the word, "enduring" best describing it. Then that would be in keeping with the "Central Planner's" vision for such a product.
The cylinder on that one was with a steel liner and were prone to seizure. Yet they said if one allowed the motor to cool for a few minutes that it would restart and run just fine. They stated the piston used in those motors were tapered to the top from the bottom where as the bottom of the piston was
barely wider than the top.
Their motors seemed to be dependable by and large with the word, "enduring" best describing it. Then that would be in keeping with the "Central Planner's" vision for such a product.
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