Skip to content
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
Skins
  • Light
  • Cerulean
  • Cosmo
  • Flatly
  • Journal
  • Litera
  • Lumen
  • Lux
  • Materia
  • Minty
  • Morph
  • Pulse
  • Sandstone
  • Simplex
  • Sketchy
  • Spacelab
  • United
  • Yeti
  • Zephyr
  • Dark
  • Cyborg
  • Darkly
  • Quartz
  • Slate
  • Solar
  • Superhero
  • Vapor

  • Default (Slate)
  • No Skin
Collapse
Brand Logo

DT125R FORUM

  1. Home
  2. Owners Build Threads
  3. DTR
  4. What temp should a dtr125 run at

What temp should a dtr125 run at

Scheduled Pinned Locked Moved DTR
31 Posts 8 Posters 4.5k Views
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • R Offline
    R Offline
    ryanjimccfc
    wrote on last edited by
    #8

    It's in the cylinder head

    1 Reply Last reply
    1
    • F Offline
      F Offline
      finnerz89
      wrote on last edited by
      #9

      My temp probe sits in the radiator fins (it's a trailtech) and the max I've recorded is 87degs.
      Bear in mind that's with waterless coolant so nowhere near it's boiling point and it runs higher anyway.

      Current bikes:
      DT125X '07
      Street Triple R '11
      Aprilia ETV1000 '02

      Previous:
      DR650RSE '96
      FJ1200 '92

      1 Reply Last reply
      0
      • Irongamer727I Offline
        Irongamer727I Offline
        Irongamer727
        wrote on last edited by
        #10

        Mine is in the cylinder head.

        declanD 1 Reply Last reply
        0
        • R Offline
          R Offline
          ryanjimccfc
          wrote on last edited by
          #11

          Mine goes upto about 88 some times just wondering if that's to hot

          F 1 Reply Last reply
          0
          • R ryanjimccfc

            Mine goes upto about 88 some times just wondering if that's to hot

            F Offline
            F Offline
            finnerz89
            wrote on last edited by
            #12

            @ryanjimccfc that's fine mate

            Current bikes:
            DT125X '07
            Street Triple R '11
            Aprilia ETV1000 '02

            Previous:
            DR650RSE '96
            FJ1200 '92

            1 Reply Last reply
            0
            • Irongamer727I Irongamer727

              Mine is in the cylinder head.

              declanD Offline
              declanD Offline
              declan
              wrote on last edited by
              #13

              @irongamer727 i have a temp reading coolant cap yea I thought it was a little hot but it seems to run fine and iv had a lot hottter engines than that

              CalumC 1 Reply Last reply
              0
              • declanD declan

                @irongamer727 i have a temp reading coolant cap yea I thought it was a little hot but it seems to run fine and iv had a lot hottter engines than that

                CalumC Offline
                CalumC Offline
                Calum
                wrote on last edited by Calum
                #14

                @declan Bear in mind, by the time the temperature at the coolant cap reaches X, it's already too late.

                Personally, I'd run the temperature underneath the spark plug using a thermal coupling, or failing that at the cylinder head.

                If your engine is bog standard, then you haven't got to worry, but once you start modifying, temperature is key to understanding the risks of detonation.

                So getting as accurate reading as possible is going to help.

                The hotter the engine, the more at risk you are to detonation. My DT runs savagely hot in traffic at idle even reaching temperatures of 110 degrees celcius.

                But you must appreciate the forumula

                pV = nrt

                The specific latent heat of a substance is increased as pressure increases. So whilst water may boil at 100 degrees at sea level, that's not the case at 1.3 bar, which the radiator cap is rated to.

                Always Originate, Never Pirate!

                1 Reply Last reply
                0
                • MiniaM Offline
                  MiniaM Offline
                  Minia
                  wrote on last edited by
                  #15

                  You shouldn't need to really worry until it sits at more than 105 or so.

                  Yamaha DT125R Blue 2002, XT 125 1982, Yamaha WR250Z 1992, BMW GS650F 1994, Benelli BN302 2015

                  declanD 1 Reply Last reply
                  0
                  • MiniaM Minia

                    You shouldn't need to really worry until it sits at more than 105 or so.

                    declanD Offline
                    declanD Offline
                    declan
                    wrote on last edited by
                    #16

                    @minia mine sits at 100 at the cap so I guess mines overheating? I don’t get coolant over boil

                    CalumC MiniaM 2 Replies Last reply
                    0
                    • declanD declan

                      @minia mine sits at 100 at the cap so I guess mines overheating? I don’t get coolant over boil

                      CalumC Offline
                      CalumC Offline
                      Calum
                      wrote on last edited by
                      #17

                      @declan As I say, pressure needs to exceed 1.3 bar, which is massive. If you imagine my car only generates 0.8 bar of boost pressure.

                      This is a why waterless coolant has its benefits. 1.3 bar of pressure is exerted on the entirety of your coolant system. It's going to be mainly the radiator that will take the most damage. The drawback is that the specific heat capacity of it is less, resulting in higher operating temperatures.

                      Always Originate, Never Pirate!

                      declanD 1 Reply Last reply
                      0
                      • CalumC Calum

                        @declan As I say, pressure needs to exceed 1.3 bar, which is massive. If you imagine my car only generates 0.8 bar of boost pressure.

                        This is a why waterless coolant has its benefits. 1.3 bar of pressure is exerted on the entirety of your coolant system. It's going to be mainly the radiator that will take the most damage. The drawback is that the specific heat capacity of it is less, resulting in higher operating temperatures.

                        declanD Offline
                        declanD Offline
                        declan
                        wrote on last edited by declan
                        #18

                        @calum have you seen the workshops videos on yt about waterless coolant I wouldn’t touch the stuff it’s a good listen either way if you get free time

                        1 Reply Last reply
                        0
                        • declanD declan

                          @minia mine sits at 100 at the cap so I guess mines overheating? I don’t get coolant over boil

                          MiniaM Offline
                          MiniaM Offline
                          Minia
                          wrote on last edited by
                          #19

                          @declan You're not overheating as long as your engine and coolant system still run efficiently. Keep in mind when water is pressurised it requires more energy for it to boil, which is why if you're riding hard on a bike your thermometer might say 105 celcius, but actually it's fine because it is pressurised and therefore your boiling point is raised.

                          And besides you will feel it if your engine is struggling, it will smell hot, you'll lose power, you'll hear it struggle at lower rpms etc

                          Yamaha DT125R Blue 2002, XT 125 1982, Yamaha WR250Z 1992, BMW GS650F 1994, Benelli BN302 2015

                          declanD 1 Reply Last reply
                          0
                          • MiniaM Minia

                            @declan You're not overheating as long as your engine and coolant system still run efficiently. Keep in mind when water is pressurised it requires more energy for it to boil, which is why if you're riding hard on a bike your thermometer might say 105 celcius, but actually it's fine because it is pressurised and therefore your boiling point is raised.

                            And besides you will feel it if your engine is struggling, it will smell hot, you'll lose power, you'll hear it struggle at lower rpms etc

                            declanD Offline
                            declanD Offline
                            declan
                            wrote on last edited by
                            #20

                            @minia it’s not something that worries me tbh I ain’t rode it in ages it’s rotting on the garden sadly

                            1 Reply Last reply
                            0
                            • J Offline
                              J Offline
                              Jens Eskildsen
                              wrote on last edited by
                              #21

                              Normal, what is normal? Outside temps vary by 20c theese days where im located. You'll have a hard time to reach 70c at the cap in the morning just cruising around, and having a hard time not to exceed 110c at the head in the afternoon on a tight track. Some valid points to where you meassure, temps will read higher in the head, compared to on top of the radiator.

                              Waterless coolant boils at higher temps, but something like Evans actually remove less heat from the engine, so...whats the point of that? I've never heard of anyone damaging a radiater due to cooling preassure. 1,3 bar isnt normal running pressure, but maximum pressure, before the cap lifts and "bleeds of" the excess. If you're worried, buy a cap with less pressure.

                              Unless it boils, its fine. Bike is designed to function with 100c or more coolant, otherwise it wouldnt have a 1,3bar cap on. Everyday use should be less of that, ofcourse. But the thermostat isnt even fully open at 80C, come on people...

                              Unless something is off, its also just about impossible to get detonation in our bikes with super low compression. I've ridden mine on 20% diesel as part of a bet, no issues.

                              Theres always small exeptions for modified engines, which generate more power and heat, but that goes for any engine.

                              1 Reply Last reply
                              2
                              • J Offline
                                J Offline
                                Jens Eskildsen
                                wrote on last edited by
                                #22

                                Btw, isnt our stock cap a 1,1? Thats what I recall anyway.

                                CalumC 1 Reply Last reply
                                0
                                • J Jens Eskildsen

                                  Btw, isnt our stock cap a 1,1? Thats what I recall anyway.

                                  CalumC Offline
                                  CalumC Offline
                                  Calum
                                  wrote on last edited by
                                  #23

                                  @jens-eskildsen 1.3 on my Starlet, I've been away from my DT so long I can't even remember.

                                  Always Originate, Never Pirate!

                                  1 Reply Last reply
                                  0
                                  • J Offline
                                    J Offline
                                    Jens Eskildsen
                                    wrote on last edited by
                                    #24

                                    Found one on ebay that said 1,1 and listed as beeing for a dt125r 🙂
                                    0_1529947732020_cap.jpg

                                    declanD 1 Reply Last reply
                                    1
                                    • J Jens Eskildsen

                                      Found one on ebay that said 1,1 and listed as beeing for a dt125r 🙂
                                      0_1529947732020_cap.jpg

                                      declanD Offline
                                      declanD Offline
                                      declan
                                      wrote on last edited by declan
                                      #25

                                      @jens-eskildsen yeah I don’t get Evans because people say it’s safe because you don’t overheat well yes you do it’s just the coolant doesent boil until such a high temp id much rather it boil over as then I know something is wrong rather that having a full rad but a melted piston

                                      CalumC 1 Reply Last reply
                                      0
                                      • declanD declan

                                        @jens-eskildsen yeah I don’t get Evans because people say it’s safe because you don’t overheat well yes you do it’s just the coolant doesent boil until such a high temp id much rather it boil over as then I know something is wrong rather that having a full rad but a melted piston

                                        CalumC Offline
                                        CalumC Offline
                                        Calum
                                        wrote on last edited by Calum
                                        #26

                                        @declan It's not about overheating. It's about the pressure not building up in your coolant system. It's a trade off at the end of the day. And since it's not water, it doesn't oxidise and rot your engine. Our engines are Aluminium, but on a car with a steel block it makes more sense.

                                        You need to take into all the factors into account.

                                        For something you are going to use once in a blue moon, it makes sense since you don't need to drain the coolant system for periods of storage.

                                        Always Originate, Never Pirate!

                                        declanD 1 Reply Last reply
                                        0
                                        • CalumC Calum

                                          @declan It's not about overheating. It's about the pressure not building up in your coolant system. It's a trade off at the end of the day. And since it's not water, it doesn't oxidise and rot your engine. Our engines are Aluminium, but on a car with a steel block it makes more sense.

                                          You need to take into all the factors into account.

                                          For something you are going to use once in a blue moon, it makes sense since you don't need to drain the coolant system for periods of storage.

                                          declanD Offline
                                          declanD Offline
                                          declan
                                          wrote on last edited by
                                          #27

                                          @calum that’s about the only thing that makes sense to me

                                          1 Reply Last reply
                                          0
                                          Reply
                                          • Reply as topic
                                          Log in to reply
                                          • Oldest to Newest
                                          • Newest to Oldest
                                          • Most Votes


                                          • Login

                                          • Don't have an account? Register

                                          • Login or register to search.
                                          • First post
                                            Last post
                                          0
                                          • Recent
                                          • Tags
                                          • Popular
                                          • Users
                                          • Groups