2016 Bonneville T100 - Question About 2 Mystery Plugs

Discussion in 'Technical Help' started by MoreCowbell, Sep 19, 2023.

  1. MoreCowbell

    MoreCowbell New Member

    Apr 24, 2021
    6
    3
    New Mexico
    Just behind the exhaust crossover tube are 2 small plugs: one that threads front to rear, and another that threads from the bottom up.

    The heads both appear to be 6.5mm Allen.

    Does anyone know what these plugs are for?

    I may consider using one of them for an oil temp. sender tap site.
     
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  2. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    55
    28
    Cheshire UK
    A picture would help....

    Wont an oil temp sensor need to be in sump oil.
     
  3. Sandi T

    Sandi T It's ride o'clock somewhere!
    Subscriber

    Dec 3, 2018
    22,259
    1,000
    Tucson Arizona
    Oh my gosh, @MoreCowbell, although I have no idea how to answer your question, I just had to respond to your post because your online name--MoreCowbell--brought a huge smile to my face. I love that SNL skit with Christopher Walken. :joy::joy::joy:
     
  4. MoreCowbell

    MoreCowbell New Member

    Apr 24, 2021
    6
    3
    New Mexico
    To NickJaxe, it is very difficult to get a good picture. I tried. The location of the 2 plugs is exactly where I described. They are also just below the starter. If you have a 2016 T100, you will see them.

    To Sandi T, I appreciate your enthusiasm. Most people don't pick up on that.
    Don't Fear the Reaper ;)
     
  5. MoreCowbell

    MoreCowbell New Member

    Apr 24, 2021
    6
    3
    New Mexico
    I meant to respond to this - good point. Yes, of course the sensor would need to be within the sump oil. The horizontal plug (below starter/behind the exhaust cross-tube) I am entertaining may meet that condition. This must be determined. Next time I change my oil. I will first remove that plug (uses 6.5mm Allen) and see if it seems to be below the oil level. If not, it won't be suitable.
     
  6. MoreCowbell

    MoreCowbell New Member

    Apr 24, 2021
    6
    3
    New Mexico
    I'd like to update this thread. After reaching out to 2 different sources in the UK, the best response I got was from Triumph Motorcycles America LTD:

    "What you are seeing is likely oil galley plugs used in manufacturing."

    This seems plausible but I still wish that I knew whether the full oil sump level comes up to the level of at least the bottom plug. (I could probably find out the hard way ...)


    Recall that I thought the plug heads were a "6.5mm Allen". Besides the fact that this wrench is impossible to find, I laid under the bike again a few days ago and probed the head a little more. After a lot of inspection, I discovered that the head isn't an Allen at all; it's Torx !! Specifically, a T-50 wrench fits perfectly.

    Without more/better information on that plug, I'm not sure where I go from here, But I at least wanted to let anyone know that the plug head is Torx T-50.
     
  7. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    55
    28
    Cheshire UK
    Wont the oil level in the sight window tell you what you need to know.
     
    • Agree Agree x 1
  8. MoreCowbell

    MoreCowbell New Member

    Apr 24, 2021
    6
    3
    New Mexico
    The level in the sight window might give me a ballpark clue ... you're right Nick. I haven't tried that but probably should.

    The very best way would be to warm up the engine ahead of an oil change, get the bike vertical with the earth, and remove the lower plug with my Torx wrench. That's what I meant about "the hard way". ;)
     
  9. Eldon

    Eldon Elite Member

    Nov 14, 2018
    5,909
    800
    North Yorkshire
    The only way to create certain oilways in manufacturing castings such as crankcases or heads is to drill right into the core from the outside. This solves one issue and creates another, the oil now leaks externally.

    If you do decide to remove the plugs, which personally I wouldn't, then ensure you use some appropriate sealant on the threads on refitting.
     
  10. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    55
    28
    Cheshire UK
    Think I would try nipping it up before removing.
     
  11. MoreCowbell

    MoreCowbell New Member

    Apr 24, 2021
    6
    3
    New Mexico

    If I get to that point, that is exactly what I would do. And actually - if you've been following this thread from the beginning - the goal, if the plug is immersed in sump oil and there is room inside, is to find a 12V sender to insert for an oil temp gauge. It may be the very best spot.
     
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