R125 Stator Assembly On R15?

Discussion in 'Technical Discussions' started by Thilak Rao, Dec 12, 2011.

  1. Sorry, if this is inappropriate here. Actually, I've been very thankful to this forum for providing the R125 Service Manual. I'm from India, and I ride an R15. I'm planning a 3000 mile trip to the highest motorable road in the world (Leh - Ladhak) and it would involve a lot of tough terrain riding through the Himalayan hills. I need to upgrade my headlamps before I can hit the road for this trip.

    Here in India, motorcycle with headlamps brighter than 35w are not road legal. I've had a dozen close calls with lazy cows, and agressive dogs cutting across the road. I have broken my right hand in one such occasion due to bad illumination.

    I was going through the service manual, and turns out, R125's stator assembly generates 200+ watts. That's enough for my R15 to decently run 55/60w headlamps. From the looks of it, even the circuit diagram looks the same:

    The rectifier/regulator unit seems to be a direct fit, but I'm not sure if the stator coil would be a direct fit on the R15. I found a guy on eBay who sells R125 stator for £39.99

    Link: http://www.ebay.co.uk/itm/YAMAHA-YZ...UK_Motorcycle_Parts&hash=item3a6d7c8137#rpdId

    Since R125 don't sell in India, and R15 don't sell in most parts of the world, I understand that it becomes a little tricky to answer this question, but please share whatever you can: Can R125 stator assembly be directly mounted on R15 crankcase?

    Any replies would be appreciated!

    Attached Files:

  2. L-J-P

    L-J-P staff Staff Member

    Best speak to Vixy, as he know the r15 he is the administrator.
  3. azz2693

    azz2693 Member

    can i ask, if its illegal to go over 35 watts then why are you going to a higher wattage bulb? im sure yor bike would have enough for the 55/60 watt bulbs, our bikes happily handle 110wats (when both low and high beam are on). if your bike is limited to an out put of 35 watts, but doubt it is, and if you want a bright light to be able to see, maybe a HID kit would be worth looking into, they only use 35 watts of power but the light output is probably brighter than two 100 watt bulbs together. these will probably be illegal too even though they are 35watt they are a hell of alot brighter :)

  4. As per the service manual of YZF-R15, the stator coil generates 160watts. The rectifier/regulator is caped at 14amperes. (14 x 12v = 168 watts). So yeah, R15's headlamps are limited to 35w, and they are pathetic. Take a look at this:
    The rules are pretty stupid here in India because bikes like Ninja 250R, Bajaj Pulsar 220, CBR 250R all come equipped with 55/60w bulbs, and they are road legal. I don't see a reason why they should make it illegal on < 200cc bikes.

    I have considered HIDs as an option, and even tried it on my bike. Couple of things I learnt about HIDs:
    1. HID makes you a cop magnet.
    2. The glare is blinding since we don't have a projector cut off. The lights bleed way too much with R15's stock reflector setup.
    3. Chinese brands do not consume 35w as stated. From my experience, they cold start at 9ampere (9 x 12v = 108w) and it takes a good 10 to 15 seconds to warm-up and level off at 3.2 to 4.5 amps. If an HID draws 4.5 amps of constant current, how can it be 35w? Chinese brands do so because they have to compete with brands like Philips and OSRAM in terms of lumens.

    When it comes to branded HID kit, I have only one option - http://www.lighting.philips.co.in/v2/automotive/productrange.jsp?id=1012984#0

    But Philips no longer sells these kits with 4200K bulbs. Due to lack of demand, they only sell 6000K, which is worthless in rain or fog.
  5. vixy

    vixy Administrator Staff Member

    the best thing really is to buy one and see it yourself.
    but i guess they are most likely compatible in terms of bolts dimensions etc..

    maybe you can take a picture of your r15 stator and post it here.
    dont forget the dimensions spacing of bolts etc..

    if i have a chance i can open up an r125 engine here and check its dimensions.

  6. Thanks for taking the time to reply here, Vixy! I have found some used parts on eBay.co.uk.

    Is it advisable to procure used parts from eBay UK?

    I'll try to source Stator Coil and Rectifier unit from eBay. From the circuit diagram, it seems to be a direct fit. I'll open up my R15's Magento, check the dimension and get back to you.

  7. Hi Viky, I found a picture of Yamaha R15's Stator Assembly. This is how it looks like:

  8. azz2693

    azz2693 Member

    yzf r125 one, not best angle and stuff but how it looks :)
  9. MikasPT

    MikasPT staff Staff Member

    Why not use a HID 35watt a 55 watt halogen bulb produces a standard 1400 lumens of light. A 35 watt HID produces a standard 3200 lumens a 35watt HID produces 128% more light than a 55 watt halogen bulb, and consumes 36% less power.
    Joshg and Tomt08 like this.

  10. I really wish, I could.. But HIDs are largely illegal in India. Cheapy Chinese HID are not reliable. I've tried my luck with them
  11. vixy

    vixy Administrator Staff Member

    maybe you can try a projector retrofit. with that it has cutoff and no glaring.
    then you can use HID on projector lamp.

  12. I've order R125 Stator and Rectifier Unit from PitStop90.com

    Hopefully, I'll get it in a day or two. I'll keep you guys posted on how things go.

  13. Got the R125 stator coil and rectifier from Pitstop90.com

    The rectifier was a direct fit, and it pumps negligibly more volts at idle RPM.
    But the stator coil was about 3mm bigger, and it didn't fit in the magento bucket. I think I might have to opt for coil rewinding now.
  14. vixy

    vixy Administrator Staff Member

    How about comparing the magneto?
    As long as the pulser length is the same with r125 and r15 you can swap it also.


  15. We
    Well, it won't fit into the Magento Rotor. The outer diameter of R125 Stator is 3 mm larger than R15. The closer the coil is to the magnetic flux, the better the efficiency of the coil. Probably that's why there is absolutely no clearance between the coil and the magneto rotor. Changing the Magento Rotor with R125's sounds like an expensive venture. Already spent 75 quid getting these shipped to India.

    R15 stator has 19 AWG Copper windings, R125 has 18 AWG. I'll rebuild the stator myself, and keep you guys posted.

    Thanks for taking time to reply.
  16. vixy

    vixy Administrator Staff Member

    oh i see, thats really the hard part of modifying your bike to satisfy your needs, in the end
    i guess its all worth it :)
    update us brother on your rewiring the stator..

  17. Yeah, that's what I'm thinking. Rewinding by hand is a very difficult and painstaking task. Need to ensure that the coil is tightly packed.

    I carefully removed the winding of the coil, and drew the circuit diagram of the coil as I was removing it. Both R15 and R125 have the same type of coil, it's just that R15 uses 19AWG wire, and R125 uses 18AWG. This is what it looks like:
    The local coil winding guy tells me that I cannot do it because the poles are so close to each other, but there are firms in U.S who specialize in this sort of things. Worst case, I'll ship my unwound Stator and get it winded by them.

  18. Update: Looks like my hand built stator gave up on me after 5 months, 10,000 kms, and 3 trackdays later!

    Need to troubleshoot and figure out, if it's the rectifier or the stator.
  19. vixy

    vixy Administrator Staff Member

    whats the update bro @thilak rao ?

  20. I had to jump start my bike for a week before I could source a R15 stator and debug the issue. Turned out the coil is absolutely fine, the connector which hooks stator to the wiring harness of the Rectifier was burnt out (read: poor Indian build quality)

    I think the solution would be DYI wiring harness using Teflon insulated cables.

    P.S: My bike has been running on R125 stator for over 6 -8 months.

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