Will A 2015 Engine Fit In 2010 Bike?

Discussion in 'YZF R125 General Discussions' started by Old125Rider, Mar 4, 2017.

  1. Hi all . As topic says would one fit in ok?
    Would I need a 2015 cdi too?
    Lots of nice low milage engines available from bikes that have been binned.
  2. Blazer

    Blazer Member

    Yes the engine from a 2015 yzfr 125 will fit, no need to change the cdi. The problem will be that the gear pedal was redesigned, meaning that the gear box is reversed in the 2015 model. Check out these schematics.
    2010 yzfr 125 16.jpg 2015 yzfr 125 16 (1).jpg .
    Last edited: Mar 4, 2017
    Old125Rider likes this.

  3. thankyou so much Blazer.

  4. Ok so looks like i'll have racing gears. Cool lol . Also i have been told the speed sensor is in in a different location . Even so I feel encouraged so far :)

  5. Just Bought a 2015 engine Woot. Only 1700 miles on it. Soon as I fit it I'll let you know how it goes and any issues. Excited :D
    Blazer likes this.
  6. Blazer

    Blazer Member

    Look forward to your update.
    Old125Rider likes this.

  7. Ok put the new engine in and I get a Flashing Engine warning 1 slow flash 9 fast flashes...Usually means ecu wire broken..? Wont turn over .So i plugged in old engine ( along side new And no faults..?) Tried to turnover old engine but Battery is flat so cant do much now till recharged... Really hope I dont need a new shape ecu, clocks and wiring loom...And then I'll have ABS faults??? Checked all connections about a thousand times...Argh! I guess I may have to trade this beauty of an engine for a reconditioned olden...

    Oh and my exhaust is out of line with the mounting points since the new shape engine has a lambda sensor extending the exhaust header...But thats ok I can make some bracket extension no problem.
  8. Blazer

    Blazer Member

    Have had same code come up on my wr before, turned out to be a problem with the generator not charging the battery, so could just be that the battery was low.

  9. I am hoping so too :D Prior to purchase I asked 6 Ebay sellers and all but one said a new shape engine will work....

  10. Ok Guys or anyone interested in the future. It works! Waahooo sounds amazing oh YEA BABY!
    oK so I charged the battery tried again and no change at all....
    Eventually....by trail and error/ process of elimination. I found the issue... It's all down to the neutral sensor it doesnt work with the old clocks/ecu . You have to trick the clocks by earthing the Sensor cable ( Cable near the front sprocket under gear shifter). Thus the Clocks/ecu thinks you are in neutral and can start the bike.
    Its a shame the neutral light is permanantly on .

    I have not gone for a spin yet she's revving nicely though...here's hoping the fuel map still works normally whilst bike thinks its in neutral....Maybe I'll add toggle switch . Cheers for now.

    Also I had to Solder the thermostat cable wires to the old style fitting. And put the old style fuel injector in since the new one is the opposite way around.. No biggie.
  11. Blazer

    Blazer Member

    Great to hear it's sorted. Hopefully it's just a faulty neutral sensor and it can be replaced, or swapped with the old one. Does the foot peg sit in the right place to be able to change gears with the re designed pedal?.
    Last edited: Mar 22, 2017
  12. Blazer

    Blazer Member

    Just took a look on AJsutton and found that your old engines neutral sensor and the new engines sensor share the same product code.

  13. @Blazer Thats interseting.. I have earthed the engine so well... Maybe its just faulty...

    Regarding the gearing I simply Turned the bolt on clamp part 180 degrees and it works as standard :D

    Another issue....The belly fairings wont wrap around the exhaust... so she looks like a CBF at the moment... Hoping a 2015 exhaust will solve this ...bit of a gamble, but i think they are cheap enougth.
    Good job I love tinkering :D
    Blazer likes this.
  14. Blazer

    Blazer Member

    Great!, so it seems like the only major issue is the exhaust header pipe, and any other issues can simply be sorted by swapping parts from the original engine. Thanks for posting your findings on here, i'm sure it will help many who are thinking of doing this. Is there any chance of posting a photo of what the altered foot pedal/ gear pedal look like.

  15. Went for a 10 mile spin No problems at all.

    Here's some photo's :
    Engine out..
    Comparing, swapping and soldering parts so they are compatable to old style fittings.
    Made a small temporary bracket to reach exhaust mount
    Gear shifter fitting turned 180' upright to keep standard gearing. New type gear leaver in the post...
    And here she is no belly fairings on till I sort exhaust out ( Exhaust header on mark two engine pertrudes to far) .. I Think most after maket exhausts go striaght down from the exhaust header so would allow my farings to be fitted...??
    Thats all for now.
    Last edited: Mar 23, 2017
    Blazer likes this.

  16. Hi guys, I have the Yamaha r125 2010 I talk with a guy to fit a 2015 engine with 4K miles and it's happened,all good until I go to ride it about 1 mile and it's stop,no starting. When they fit the new engine they fit new carburetor and air box but after I go riding the flashing light engine show up and doing 1 time after 4 time. I see the codes and looks like it's the hoose it's not connected , I take the plastic off and see the the hoose from exhaust it's not connected and I swap the new air filter box with old,still not working, i change the carburetor(old one) and air filter box(old one) with K&N filter back, it's Starting all good but the Flashing light engine it's still there.(before the old engine have a 180cc bore kit and dynojet power commander V) .how do I sort this problem if someone know? Thank you
  17. Blazer

    Blazer Member

    The engine should run ok with the original throttle body, injector and airbox. The new engine has a lambda sensor on the exhaust port which the 2010 bike does not need, so if it's connected to anything this could be your problem. Did they also change the ecu?.

  18. No ,the ecu is the same should i change it? I just read again about error 1-4 maybe the intake sensor it's bloked i will Look tonight and keep update.

  19. The Lambda sensor it's Not connected because i check twice.

  20. Blazer do you think if I will fit the power commander back(dynojet power commander v) it's will make any difference?

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