• Hello everybody, now I'm look at getting a Dt125 as my first bike, now I have a few questions about the oil and coolant. Gearbox oil what oil would I need how much and how often would I need to change it. Engine oil what oil would I need how much and how often do I need to top it up, and coolant is it just any coolant for a car etc how much and how often would I need to top it up. Sorry the seemingly silly questions I just want to to know the rough cost of running the bike before I get one many thanks. 🙂

  • Gearbox oil is 10w30 engine oil, or lightweight gear oil of the same rating. As long as it's suitable for wet clutches you'll be fine. I've just put this in mine

    Castrol Power 1 Engine Oil 10W-30 4T, 1L https://www.amazon.co.uk/dp/B0064YM5PO/ref=cm_sw_r_cp_apa_CZrQzbRKNBQ3M

    As for engine oil, I use Silkolene, others swear by cheaper oils so I guess that's up to you.

    Fuchs Silkolene Comp 2 Plus 2-Stroke Engine Oil 1 Litre https://www.amazon.co.uk/dp/B071DP83WW/ref=cm_sw_r_cp_apa_t0rQzb5EV2CVX

    And coolant, I use premixed coolant suitable for aluminium engines. Given the price and small amounts of gearbox oil and coolant needed, I'd change them yearly, but every other year would be fine I'm sure.
    Engine oil usage depends on how you ride, as more throttle=more oil used. Unless you're running premix. I can just about squeeze a litre of oil into mine once the light has been on for a few miles.

    Hope this helps

  • So long as you don't get castrol magntec oil you should be fine.

  • Hi, yes thanks very much that helped a lot, so for gearbox oil any engine oil as long as it's 10w30 does it have to be fully or semi , and for engine oil any decent 2t oil I take there no 10w30 or 10w40 for this also does it have to be fully or semi ? Lol and coolant any premixed coolant should be fine? And change the gearbox oil and coolant at least once a year ? And top up up engine oil when necessary. Many thanks. Again sorry I'm very very new to all this 2 stroke malarkey and want to make sure it is well maintained.

  • @yamahaman5000 For the gearbox I have always used castrol gtx semi-synthetic 5w-30.

    Two stroke doesn't have those properties specified. But any decent oil should be sufficient, I prefer silkolene fully synthetic.

    Coolant, I personally have gone for evans waterless coolant, but I used to use CarPlan premix. But each to their own for that one.

    Engine oil, well light comes on and you fill it up.

    Gearbox oil should be replaced according to mileage, if you do lots of miles, then replace the oil.

    The oil is designed to be replaced after 10k miles in a car, so probably doesn't need replacing in a DT. Replace oil when you do the piston and rings, approx every 10k.

    But again it's all down to how you ride.

  • Thanks for help, that's cleared everything up. 🙂 . Is there anything I should look for when buying a dt 125. So you recommend changing piston and rings every 10k is there a kit I could buy online all in one. I know a friend who would do this for me if needs be so should save a lot of money on Labour etc.

  • @yamahaman5000 These bikes are pretty bullet proof. I do piston and rings every 10k because my bike isn't in stock trim.

    I had my bike stolen and ramped and battered on the stock piston for 15k miles and it was in mint condition.

    I err on the side of caution, but others will be happy to leave the engine till its seriously down on power.

    It's cheaper to replace rings earlier than necessary, rather than to have the engine fail and need a full rebuild.

    Many people rebuild the head gaskets using cheap pattern parts, only Genuine or Athena gaskets can be used.

    In which instance the head gaskets tend to be blowing because people "can't" fix them.

    If that's the case it just needs a gentle skim and a decent head gasket. Clues to this will be the expansion bottle missing the little cap, usually the first thing to go when the head gaskets gone.

    There will be a layer of black oil circulating around the radiator system, take the cap off and run your fingers inside and you will be covered in oil

    The swingarm bearings wear and don't get replaced. Pull the bike on its stand, pull it off the wheels over to you and check the swingarm for side to side lateral play.

    This is less common, but is just general advice for DT's.

    They're pretty darn strong bikes, there doesn't tend to be common faults that need looking out for.

    Generally, pay extra for a better condition one and it'll serve you well.

  • And note, not all 2-stroke oils are suitable for premix. Make sure it says so on the bottle, unless you mix it up yourself.

    Just about any half-decent 2-stroke oil will do, but most use some of the best, as the pricedifference per mile is so small nothing.

  • What do you think about this oil?


    It's about £36 for 4 liters.

  • @irongamer727 But the gearbox only takes 750mls....?

  • @calum I have more than 1 bike and will change for more than 1 time..

  • I'm asking for oil quality only, which is the best.

  • @irongamer727 It's subjective I guess. Personally I run Silkolene oils for my four strokes. But currently running Castrol in my Starlet as a quick fix. It's leaking it all over the floor so need to sort that out.

  • @Calum why not castrol?

  • @irongamer727 To each their preference. My mate works in the oil industry for motul, so when I need oil I just ask him and he'll bring the best stuff 😛

  • @minia I think each to their own. No reason, I just prefer Silkolene.

  • It just feels so hard choosing. I want the best possible oil for my machines!

  • @irongamer727 As long as you stick with the bigger well-known brands you can't really mess it up. As for types of oil I use yamaha 10w-40 4t for my gearbox and motul 100% synthetic 2-stroke oil for the engine for all my 2 strokes. If I don't have motul, I just go with castrol.

  • @minia I run Castrol Power 1 2T Racing in all my machines. Cheap and hopefully good.

  • @yamahaman5000 I always found that Silkolene products were very high quality and performed very well indeed. 😉