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2T Single-Ring Piston Conversion?

Discussion in 'Technical and Troubleshooting Torque' started by boingk, Apr 11, 2009.

  1. Hi there. I've got an Aprilia RS125 thats due for a top end rebuild in a few thousand kay and I'm thinking of getting a single-ring race piston kit for it, instead of the usual two-ring affair.

    I'm not exactly sure how this will affect reliability, maintenance and power delivery. I figure that it will reduce the top-end life somewhat, but am unsure of whether I would need an uprated bottom end as well.

    If you've had experience with this sort of thing, or just have a bit of knowledge, I'd greatly appreciate any advice.

    Cheers all - boingk
  2. Check out the 125 forum link from your other post :)

    Essentially if you want to reduce friction losses and willing to have a shorter ring life, do a single ring rebuild. For the road, I'd be happy with a normal (double) ring piston.
  3. I'd be willing to bet that you wouldn't notice the difference on the street. No detrimental effects to the bottom end either.
  4. just a guess (somewhat educated though?!?)

    wouldn't you need some major dyno/ecu work to make it even worthwhile, seeing that you'll hit the rev limiter at around 10500 I think... and it's virtually pointless?
  5. Spot on Mekros, you will notice a little performance gain, but less ring life. New ring replaced a little earlier.
    Go for it though of you're doing it yourself.
  6. Righteo guys, thanks for the info. Also searched the sites you mentioned earlier, mekros. Didn't find mountains of info but did stumble across a nice pic-by-pic thread on how to rebuild the top end. Sweet!

    AhrimaaN - Not sure what you're talking about...my bike certainly doesn't have a rev limiter, and anything to up the power on small displacement bikes like our is a plus. I mean, gain 3hp and thats a 10% gain! Not huge numbers, but I've always though extracting the most from your machine is a worthwhile (to a certain extent) and fun (for me, at least) thing to do. I'm also definitely willing to sacrifice a bit of reliability for performance. Not all of it, mind you, just a bit. :grin:

    Are you referring to figure at which maximum power is developed? I'm fairly sure this is around 10,500rpm, and may well rise somewhat if a single-ring setup is substituted. Lower frictional losses and a slightly lower top-end weight dictate this, not the ECU. I imagine I will have to rejet the carby though, and a performance air filter and silencer wouldn't go astray either. Dyno time is definitely on the cards, pre and post-mod graphs will definitely help sort issues out. I'll let you know how I go, hey?

    Cheers all, I reckon I'll go ahead with it - boingk
  7. Atleast this way we'll know how many kilometres a single ring setup will last :)

    Cheers for the update and keep us informed.