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nudemetalz
16th June 2010, 10:58
Just a general question here.
Can a 2-stroke can be run on 1 ring instead of 2 ?
Would it make much difference to how it runs?

I notice that TZ and RS125 pistons have only 1 ring. Is this to do with tighter clearances?
bogan
16th June 2010, 11:05
all dirtbikes I've owned have only had a single ring, could be a durability issue as dirtbikes need rebuilding more often than others with more rings :scratch:
nudemetalz
16th June 2010, 11:06
hmm,..interesting, thanks Bogan.
bogan
16th June 2010, 11:08
just had another thought, two rings may hold oil better than only one, so if you go down to one ring, the mix may need to be altered to prevent seizing. Typical mix in my mx bikes have been between 32:1 and 38:1
Crasherfromwayback
16th June 2010, 11:10
Just a general question here.
Can a 2-stroke can be run on 1 ring instead of 2 ?
Would it make much difference to how it runs?

I notice that TZ and RS125 pistons have only 1 ring. Is this to do with tighter clearances?

Less drag with one ring, and running with one is fine mate.
nudemetalz
16th June 2010, 11:20
So if I was only going to run one ring in my Fizzy, which would be the better slot, top or bottom?
Figured it may affect the port timing of my 5hp beast,....err,..sorry,.. 2.5hp moped......


edit - just spotted this thread http://www.kiwibiker.co.nz/forums/showthread.php/64442-Single-ring-piston
big oops !!
Crasherfromwayback
16th June 2010, 11:32
It won't affect the port timing mate...the top of the piston determines that! Remove the lower ring, not the top ring.
nudemetalz
16th June 2010, 12:00
Thanks for the advice, Pete
Crasherfromwayback
16th June 2010, 12:02
And 25-1 mix gives you better ring sealing than 35-1 etc too mate!
schrodingers cat
16th June 2010, 17:58
And 25-1 mix gives you better ring sealing than 35-1 etc too mate!

More oil (25:1 rather that 35:1 or whatever) also lowers the octane rating of the fuel. Wouldn't imagine your port/ignition timing is so critical for that to be a deal breaker
Keep an eye on the ring groove clearance. Depending on how close the lower ring groove is to the top, the top groove may open up a bit quicker than usual. Again, its not likely to be anything catostrophic.
Crasherfromwayback
16th June 2010, 18:32
My KX500 made more HP and torque on our dyno at 20:1 than it did at 33:1 easily. No pinging either.