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Engine

Engine Related
498 Topics 4.9k Posts
  • This topic is deleted!

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  • Cutout acceptable?

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    Louis-DT-WRL

    My wr200cc/dt125r hybrid engine runs with lid cut off. I ran it also with the 125 engine. You just need to jet accordingly.

  • Billet Head

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    CalumC

    @ninja As a general rule of thumb, the greater the compression ratio the lower torque spread but the greater the peak power. I don't know the figures, but I'd look to go with a domed head.

  • 2002 3MB cylinder bore size.

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    All depends why reboring it, if the cylinder measures size you say then never been rebored. The cylinder on your year although called 56mm is actualy 55.95mm, if the cylinder is not damaged then just get it honed. If honing the cylinder then this piston is what you need.
    https://www.ebay.co.uk/itm/Yamaha-DTR125-DT125-R-DTR-125-56-25mm-Bore-Namura-Piston-Kit/292513505226?hash=item441b29dfca:g:jyEAAOSwwbdWQwnA

    Whatever size piston you buy whoever is reboring it will bore and hone to match what piston you supply. The best reboring is done by Karl at KPM as had them do a
    few and also by PJME. Karl charges £30 for a bore and hone with return postage at £10-16 postage depending on courier and insurance required.
    He will also fully port your cylinder for £100, just have to tell him what your after like more midrange etc or more mid and topend like a YZ.
    http://www.kpmotosolutions.com/

  • Installing clutch plates

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    Irongamer727I

    The DT has now undergone a kickstart conversion! Feels so cool!

  • Tiny coolant leak.

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    Irongamer727I

    @sgt-robuck-5 doesn't work like that. Air pushes coolant up in the expansion tank filling it and then spits out on the road. Then returns to normal once cool. Just open the radiator cap and bleed it, problem solved.

  • Pv actions

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    declanD

    @irongamer727 I’d say so yes

  • 3SH belgarda engine

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    CalumC

    Aww cool, it's a belgarda engine.

    Italian import, you get mega props for owning one. They have wicked Motori Minerelli Stamps where the original DTR engine doesn't. It's super cool engine.

    Slow as balls though. It's just not comparable to the SP.

  • Is £58 a reasonable price?

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    declanD

    @calum That’s pretty cool might have ya have a check some day

  • Pilot jet advice

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    DartyD

    @irongamer727 The stock Pilot Jet is (25) , My advice is to try (27.5) to support your mods.

    Also dont forget about Needle height! Very important aswell

  • Gasket clutch side

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    CalumC

    That will also do

    alt text

    The clutch cover gasket doesn't need to be anything special.

  • 3bn03 or o3

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    declanD

    @irongamer727 for what bud?

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    CalumC

    Right also, don't be so quick to slate Yamaha for using the bolts that they did.

    I'm not going into here, you can easily Google that information, but trust me when I say there is a perfectly justifiable reason as to why they used the bolts that they did.

  • 0 Votes
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    declanD

    @gilera-sc you have the best of knowledge right here on this forum

  • Slipping clutch after rebuild

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    CalumC

    Mine slipped with Castrol Magentec. I just use Castrol GTX Semi 5-30w

  • Break in new cylinder

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    Glynn123G

    I've always done about 5 heat cycles then a gentle ish ride before riding normal, never had any of my rebuilds seize or fail, obviously you don't wanna be holding it wide open for 2 or 3 rides but don't be afraid to accelerate, with a good forged piston and a few heat cycles you won't cause any harm.

  • Clutch issue?

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    O

    Used 10w40 gear oil in mine with no issues, did replace clutch in 89 and suspect original plates contaminated as very "sticky" when I got them out

  • dragging clutch.

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    Sgt Robuck 5S

    Took it into my college to ask my tutor what he thinks. (he builds race bikes) he said it looks fine and I could file it down very lightly. he also said the scratches on the outside were fine.

  • 1 Votes
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    terry.tzT

    :grinning_face: :smiling_face_with_open_mouth: :smiling_face_with_open_mouth_smiling_eyes: :grinning_face_with_smiling_eyes: :smiling_face_with_open_mouth_closed_eyes: :face_with_tears_of_joy: 🤣 🤣

  • Fuel hose inner diameter?

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    tunertomT

    the proper cotton braided fuel purpose hoses last a lifetime

    using clear ones for fuel is asking for trouble, they go brittle, crack, split, leak and are toss!

    you dont need clear ones, there is 2 filters in the petcock and theres a filter in the carb fuel inlet barb too