Skip to content

Engine

Engine Related
503 Topics 5.0k Posts
  • Polini vs OKO PWK carburetors

    13
    0 Votes
    13 Posts
    405 Views
    Glynn123G

    Ive been off this forum for a good few months now but I went through a lot of tuning with a Polini PWK 32mm on my DTRE. On standard engine it took a lot of jetting and needle changes to find one that worked but when it was done it had a little more torque than stock. I had plans in the pipeline for a new engine build and programmable ignition which is why I changed the carb, my engine was worn out when I tried it at first but it does work and go well, you'll need to adapt your throttle cable. I have now built my new engine up with ignitech ignition and advanced map, carbon reeds etc and it needs rejected but goes very well, unfortunately I haven't had the time or enthusiasm to go on any bikes since spring last year but if I get round to it this year I will finish tuning the DT and write more on here, I have wrote some stuff about the polini carb on here before, I'm not sure if you seen it or not.

  • 3 Votes
    43 Posts
    5k Views
    O

    As I have finished the 1988 bike looking for something to do. Seriously looking at doing this to keep me busy. I'll have to look around and see if I can find the parts needed. Nice job!

  • Coolant overflowtank

    7
    0 Votes
    7 Posts
    167 Views
    J

    ill test it when i have time with haynes manual

  • Clutch will not engage

    5
    0 Votes
    5 Posts
    218 Views
    Haako SmithH

    @Calum Thanks for answering.

  • Oil pump

    3
    0 Votes
    3 Posts
    152 Views
    clawsC

    @jonne123 i mean it depends on you. if you want to mix oil yourself then go for it. but i haven't heard of those oil pumps failing

  • 1994 Yamaha Dt 125 RE Carb Replacement Advise

    7
    0 Votes
    7 Posts
    2k Views
    Walney-ReptilesW

    @dtre94

    hiya buddy sorry to hear about your problems, where abouts are you in the world? i work in a garage in the northwest and i could fix this for you if you nearby... let me know 😉

  • DT125X cooling problem

    14
    0 Votes
    14 Posts
    497 Views
    declanD

    @SouthWalesYammy I had the same problem mine fixed it’s self) EDIT) the only thing to do with cooling i changed was the radiator cap maybe that was the issue?

  • Zeeltronic system.

    10
    0 Votes
    10 Posts
    516 Views
    Walney-ReptilesW

    Any updates on this?

  • Floydy Racing

    4
    0 Votes
    4 Posts
    246 Views
    O

    Had a look, impressive work, love to have those skills

  • Float gap on the the crankshaft

    3
    0 Votes
    3 Posts
    159 Views
    M

    @DTR-NSR cheers for that buddy

  • Loud rubbing noise

    1
    0 Votes
    1 Posts
    114 Views
    No one has replied
  • Cylinder head stud length

    1
    0 Votes
    1 Posts
    161 Views
    No one has replied
  • Cylinder Head Nuts

    4
    0 Votes
    4 Posts
    211 Views
    CalumC

    @SouthWalesYammy Stainless doesn't love tension. They don't like to be stretched. But the head bolts are like 11nm so don't need a lot of force.

  • Take off oilpump/autolube

    12
    0 Votes
    12 Posts
    404 Views
    clawsC

    @HassePallisgaard well you can remove everything else but you should leave the pump in its place since it can act as the cover plate. i think that removing it doesnt make a difference but you do you

  • Power jet

    2
    0 Votes
    2 Posts
    299 Views
    P

    Hi , Matthew . I had the exact same problem as you. My temporal solution was indeed to place a clip in the tube of the power jet, thus fully restricting it and fitting a 210 main jet. Even then, on full throttle I was running on the rich side, which made the engine to bog and not go above 8k rpm.

    I managed to fix it some days ago. I will make a post with pics on the whole procedure sometime around the next month when I will have the time, but here’s some things I did to look into:

    Fully clean the carburetor body and jets using an ultrasonic cleaner. Replace all the O-rings with new ones. Replace the needle valve with the seat with brand new ones. Adjust the float height to the Hayens manual specifications.

    After the rebuilt I went from running rich and having hesitation on fast openings of the throttle to actually running a tiny bit lean with crisp response .

    *The lean is probably due to the 210 main jet I’m using instead of the factory 240 one. *

    If you haven’t changed any of the jets, I think the above steps will help you.

    Also be sure to make a plug chop using a new spark plug to verify that you are not running overly lean or rich before and after the rebuild .

  • Petcock/fuel tap help

    4
    0 Votes
    4 Posts
    230 Views
    J

    Thanks guys it's all sorted now I put a rubber o ring on the screw and it works mint 👍

  • Fuel setup

    2
    0 Votes
    2 Posts
    153 Views
    CalumC

    Higher octane fuel from the petrol station won't really affect you too much.

    It could just be a bad set of gas from the station.

    Should try refilling it back up again.

    Higher Octane fuel, if you're wonder, contains anti-knock properties. This property stops the engine detonating.

    The reason why companies say it makes more power, or better on fuel, doesn't reside on the fuel alone.

    It resides in the ability to utilise the higher anti-knock properties.

    For you, on a stock DTR, what would this mean? Nothing. It means absolutely nothing. It doesn't mean more power in any way shape or form.

    If you were in a modern EFI car. It means that the ECU could advance the ignition slightly to utilise the higher knock qualities of the fuel.

    But since our bikes are carb, and I presume you're fairly stock tune, then no, it means nothing.

    Me on the other hand, I run higher compression, more agressive advance ignition, higher combustion temperatures. All of those encourage detonation. Thus, higher octane fuel is a must.

    There really is a lot to fueling, this was just a quick dump of information. Read Graham Bell's Two Stroke Performance Tuning if you want more information.

  • ULEZ & The DT

    6
    0 Votes
    6 Posts
    447 Views
    Louis-DT-WRL

    Run it with some methanol.. that will reduce emissions. Although you need to upjet

  • Dt125x carb

    1
    0 Votes
    1 Posts
    175 Views
    No one has replied
  • Stator plate/Flywheel positioning.

    9
    0 Votes
    9 Posts
    246 Views
    J

    Thanks mate.