Street Triple Oil Leaks

Discussion in 'Triumph General Discussion' started by Justin_dunn46, Dec 30, 2025.

  1. Justin_dunn46

    Justin_dunn46 New Member

    Nov 9, 2025
    13
    3
    South Africa
    I find after a hard ride, there's a bit of an oil leak. More of a sweat.

    Does anybody know if this is common in this motor? Is it just an o ring that isn't sealing properly? All help is much appreciated.

    Bike is 2023 street triple with 9000km on it.

    20251230_082949.jpg
     
    • Like Like x 1
  2. stinger

    stinger Senior Member

    Nov 28, 2017
    793
    243
    Yarnbrook
    I have had my street triple 8 years and have noticed the same once or twice. I just nipped up the oil filler cap a bit tighter, did the trick for me. Just by hand i might add, not using any sort of pliers. If memory serves it really only happened after a "spirited" ride in warmer weather. Made me wonder if there was an expansion issue with the engine casing. Just for information my bike is a 2015 675.
     
    • Agree Agree x 1
  3. Justin_dunn46

    Justin_dunn46 New Member

    Nov 9, 2025
    13
    3
    South Africa
    Okay thats interesting! Yeah I'm down in Cape Town and summer has been REALLY hot this year. So I'll just clean it and tighten it up thanks so much
     
    • Agree Agree x 1
  4. Eldon

    Eldon Crème de la Crème

    Nov 14, 2018
    9,091
    1,000
    North Yorkshire
    Check the following;
    1. O ring on the caps condition
    2. Ensure the breather system is clear and pipes aren't trapped i.e. under the tank.
    3. Oil level is correct, dipstick fully screwed in NOT like Honda's with it hovering above the threads.
     
    • Like Like x 1
    • Useful Useful x 1
  5. Iceman

    Iceman Crème de la Crème

    Apr 19, 2020
    2,948
    1,000
    Lancashire
    It is a common problem, just replace the O-ring with a new quality aftermarket one, the anodised aftermarket Triumph ones don't seem to leak at all, different manufacturer, I guess. However, my advice would be replace it befor eyour next ride out. In the summer I set out for a day's ride, about 2 mile sinto the ride and into a tight series of bends, when I had a huge slide, and I mean huge. I parked up to have a look, and there was oil all over my boot, the footrest, the exhaust, and the culprit of the slide, the rear tyre covered in oil. The O-ring was letting oil past. I replaced the dipstick with a new anodised one, never had an issue since then. Not all machines suffer from this, the newer STRS are known for oil leaks, including porous cylinder heads. Since production moved overseas, it is either the QC or the independent parts manufacturers who supply Triumph that are the issue. The last purchase I made for a number of parts from Triumph, included China, India, Portugal, Taiwan, Germany, and the fasteners from the UK.
     
    • Useful Useful x 2
    • Agree Agree x 1
  6. ajc400

    ajc400 Senior Member

    Jun 4, 2024
    956
    243
    Glasgow
    Often, owning a Triumph seems to be about nostalgia, but adding oil leaks is just going too far!! :joy:
     
    • Agree Agree x 5
  7. thc

    thc New Member

    Feb 20, 2018
    23
    3
    Sussex
    ...As Iceman has said, it is common problem. Had the same & I too just replaced the filler cap with the triumph anodised one. Having now read Iceman's post, i will also be replacing the dipstick as well, pronto! I'd not heard of porous cylinder heads, but...in response to someone having the same problem as I had, I recently posted this on the TriumphRAT forum: "Scenario...out for a sunny afternoon ride, bike running beautifully...not long back from the Isle Of Man, where I must have done over a thousand miles on that trip alone, earlier in the summer spent three months in the Pyrenees (French and Spanish sides) no problems at all with the bike. Anyway, stopped for a pint at a lovely pub, went to leave...bike doing exactly what yours appears to be doing..fuel pump primes, turns over but not starting. Call out the AA, no ideas from them, call a local garage who come out and pick up the bike, take it back to the workshop and leave it with them. Call the following day, 'come and pick her up, all fine just fouled plugs. Phone call shortly after, same problem upload_2026-1-7_0-15-21.gif Long story short(ish) after several weeks trying several things, including a 'sniff test' for head gasket (which it passed with no signs of that being the issue, despite everything pointing to just that!) they discovered a hairline crack in the middle cylinder!! So, one secondhand engine sourced from eB*y later, I got up and running again. Severely out of pocket but thankfully for the past year and a half she's still running beautifully!"...having now heard of potentially porous heads, I'm feeling a little paranoid about my replacement engine to say the least!
     
  8. Regit nogara

    Regit nogara Active Member
    Subscriber

    Apr 22, 2025
    175
    43
    North, North Wales
    My Tiger 900 Aragon been weeping from filler cap from day one. Taken your advice.
    Just ordered a silver metal one from Lind Triumph, on offer for £15 + £4.99 P&P.
    Thanks for the info.
     
  9. TRIPLE X

    TRIPLE X Senior Member

    Sep 1, 2021
    678
    243
    Norfolk
    I have found in the past that the oil filler cap o-ring was a sloppy fit and prone to distorting if overtightened. I replaced it with a tighter fitting o-ring from a mixed size pack from Halfords.
     
Loading...

Share This Page