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Thread: Am6 pipe change. Jet help

  1. #1
    apriliaforum newb
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    Am6 pipe change. Jet help

    Hi i recently bought at am6 engine 2018 rieju mrt 50 for my brother completely stock. I changed the stock pipe to a yasuni pipe with no restrictors in the pipe. Ive been trying to get the jets right in the dellorto phbn 16 which came stock with a 84 main jet. And 36 pilot and 45 choke jet. I have a set of main jets from sizes 90 - 108 and also have 2 pilot jets size 50 and 55, the new pilot jets do not have the atomisor as the standard one does. Will this matter and anybody have any idea where to start with the jets? Is it just the main and pilot jet that needs changing or needle position to? Any help is much appreciated. Heres a couple photos of the new and old pilot jets. Top photo is pilot jet and new pilot jet on right of the photo, 2nd photo is where the pilot jet came from and bottom photo is choke jet?

    Many thanks, jClick image for larger version. 

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  2. #2
    apriliaforum Junkie
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    I would suggest the 90 main jet is going to be somewhere near to start with. Probably a little big, but it will be safe at least.
    You should get away without changing anything else at the moment tbh. I assume it ran fine before changing the pipe?

  3. #3
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    Quote Originally Posted by dac69er View Post
    I would suggest the 90 main jet is going to be somewhere near to start with. Probably a little big, but it will be safe at least.
    You should get away without changing anything else at the moment tbh. I assume it ran fine before changing the pipe?

    Thanks for the fast reply! Yes it ran fine before changing the pipe but was a restricted pipe. Will try 90 main tomorrow and see how it gets on. Any idea about needle position? Thanks again

  4. #4
    apriliaforum expert Scoop's Avatar
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    Are you sure the Yasuni you are fitting is suitable for 50cc engine? Many of them are for use with Big Bore kits and you will always struggle to tune it for the smaller engine. Needle starting point should always be middle slot and adjust from there. What exactly is the performance problem?

  5. #5
    apriliaforum Member
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    which yasuni r1, r2, r3?
    when you replaced the pipe you did block off the emission control pipe?
    when you derestrict a rieju you only normally need to change main jet leave everything else alone correctly setup with suitable gearing you should see 65MPH given a long enough road
    I have set several of these up

  6. #6
    apriliaforum Member
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    you may consider larger carb and 70cc kit as next stage
    if the bike has done more than 5000miles have you check piston for wear?
    these normally need replacing between 5-10K miles

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