Thruxton Starter Motor Oil Leak

Discussion in 'Thruxton, Scrambler & Trident' started by Nickga, Aug 6, 2020.

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  1. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    Hey, i have finally discovered the source of a long-standing slow oil leak, the starter motor O-ring. I have ordered the new oring but I am having a tough time reinstalling the starter motor.. it's doesn't seem to fit back in place. Does anyone have any experience with this or tips to provide?

    Thanks,

    IMG_20200802_194439.jpg
     
  2. Don the Don

    Don the Don Bigger Than The Average Bear

    Nov 5, 2019
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    Hi and welcome, sometimes it helps to put the bike in gear and gently rock the back wheel to ease the motor back in place, it's worked for me.
     
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  3. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    Thank you Don, I have tried that as you suggested but no luck. I may have taken on something beyond my ability but the starter seemed very simple to remove.. not so easy to put back! I have inadvertently removed the cap of the starter motor and I think I am not putting it back on correctly. Am I correct in assuming these small retractable metal blocks must "hug" onto the brass colored part of the starter shaft? If so i am not sure how best to do that...

    15967393946626485026480155086251.jpg

    15967394605372442568912685507282.jpg
     
  4. Don the Don

    Don the Don Bigger Than The Average Bear

    Nov 5, 2019
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    those four items are the brushes they should fit over the commutator, the black area is where they have been in contact, so the answer to your question is yes, you can ease them over with a very small screwdriver taking care and easing the two parts together
     
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  5. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    Thank you for clearing that up! I had suspected that... This will require patience and a steady hand hah.
     
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  6. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    #6 Nickga, Aug 7, 2020
    Last edited: Aug 7, 2020
    Don, thanks again. After spending more time then I would like to admit trying to get the brushes back onto the commutater, I found an even smaller screwdriver (one you would work on jewelry with) and finally got it back together.

    Put the new oring in started her up, and the slow leak is still present.. I am now wondering if maybe the leak is coming from behind the round metal part which you install the starter into (starter receiver?) I removed the "starter receiver" and cleaned it, the oring holding it into the engine seemed ok. Gonna put it all back and try again. Any comments would be appreciated.
    Thanks,

    Nick
     
  7. Don the Don

    Don the Don Bigger Than The Average Bear

    Nov 5, 2019
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  8. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    Yup, I had seen that thread. I found the starter diagram for my water cooled bike and I'm pretty sure I had ordered the correct oring. I cleaned everything out again and I will try and run the bike and see if the leak is there again... Third times the charm I hope!
     
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  9. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    So I have an update on the oil leak. I managed to replace the shaft seal and the oring which holds the starter into the bike engine but the leak is still present. I am still pretty sure the starter is the source of the leak. I have removed the starter, cleaned the area and rode the bike more than a few times now and I am still convinced. Does anyone have any ideas? The local triumph dealer has been unresponsive..
     
  10. Callumity

    Callumity Elite Member

    Feb 25, 2017
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    Nr Biggar
    With the starter mounted over the gearbox and under the throttle bodies it is not an obvious place for a leak..... it doesn’t sit in oil nor have an oil supply. The pinion will get splash lubricated but you shouldn’t have too much crankcase pressure pushing oil that way.

    However, there are two O rings; not just the pinion but the motor body with the ring visible in the engine casing. Are you sure the leak isn’t higher and forward but blowing back in the slipstream and pooling?
     
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  11. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    I will try investigating elsewhere as you suggest. But if you scroll to the top of the thread you will see a pic of the oil buildup inside the starter cap around where the starter shaft goes. Not sure if that is normal... also, the highest point that I see oil pooling is in the "troff" under the starter. I've cleaned and taken the bike for short 15 minute rides and it always re-accumulates there.
     
  12. Callumity

    Callumity Elite Member

    Feb 25, 2017
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    Nr Biggar
    I can see lithium grease where the pinion fits but no tell tale drip down the casting to the outer O ring and thence into your trough - though you seem to have thoroughly cleaned the creux. Your thoughts?!

    If the outer O ring is doing its job oil should accumulate inside the motor housing and pour out when you unscrew. It might help if the problem persists to photograph it dirty. Hot oil is semi invisible on black cases but clean kitchen towel can reveal its path.
     
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  13. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    That first picture does show the green synthetic engine oil on the inside of the starter cap.. when it drops down under the starter it flows down that trough and towards the other side of the bike... I have not found another place the oil might be coming from...
     
  14. Callumity

    Callumity Elite Member

    Feb 25, 2017
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    Nr Biggar
    I am limited by the resolution of the photo but I can see what appears to be oil glistening at 3 o’clock and the outer o ring looks chewed from there to about 7 o’clock but that may be shadow. Am I imagining oil on the lower engine fins?
     
  15. Nickga

    Nickga New Member

    Aug 6, 2020
    1
    3
    Montreal
    No I there is no oil on the fins.. I thought at first the the gunk around the seal was a chewed seal but It cleaned out quite easily more like funk. I brought the starter to a seal specialist and he replaced my shaft sea with another similar looking one. I wish I could see the inside of someone else's starter to know for sure if I am missing an additional seal or oring of some kind.
     
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