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Bigger engine for Aprilia RS125

Discussion in 'Modifications and Projects' started by BiaggiWNB, Oct 17, 2014.

  1. Hi all,

    So, I'm thinking of replacing my Rs 125's engine with a 250-400cc one and just wondering if anyone can suggest a good mechanic, place to buy the engine etc.

    I love my bike, I don't want to upgrade, I know this project doesn't seem to be feasible/logical...

    Any help much appreciated!

  2. i'd suggest a 13B with a mild extend port
  3. 13B lol turbo one yeah? :)
  4. Two stroke or four?
  5. 4 stroke but I'd love to chuck in a 250cc 2T.

    This is also where I need help, I'm not even sure if a 250cc will fit in the engine bay.
  6. #7 Ljiljan, Oct 17, 2014
    Last edited: Oct 18, 2014
    4 stroke is A Bad Idea. 200 or 250 two stroke I would recommend. A well known dirt bike workshop should have some engines lying around.
  7. The chain is on the opposite side to most other motorcycle engines on the rs125 so you would have to think about a different rear wheel and probably modding the swing arm. It would be an awesome mod though, 250 2t in a rs125. I loved my rs125 but the 125 can be a bit hard to live with in day to day riding.
    • Agree Agree x 1
  8. If you do contact twinrock, tell him CrazyCam said "Hello".

    I remember him from when he got a Mito, removed (or didn't get) the fairings, and fitted an RZ350 Yammie motor into it.
  9. Just sell it and buy a 250. Or to save time go and flush $4000 down the toilet
  10. cr250 engine has output sprocket on same side as rs125, which is why I said go to a dirt bike shop. I'm sure there is more than just the one.
  11. Hey guys,

    Thanks for all the replies.

    Just to clarify, my bike is 4 strokes and I'm after a 2 stroke engine, however if the engine bay allows I'll have no issues putting on a 300-400cc 4 stroke engine.

    The chain is on the left btw.

    I'll visit some dirt bike shops today and see what they come up with.
  12. #13 Ljiljan, Oct 18, 2014
    Last edited: Oct 18, 2014
    I am Jack's amused scepticism.
    Your bike doesn't happen to be a rs4 by any chance?
    • Winner Winner x 1