max bore on dtr



  • what is the maximum bore i could go to on my dtr i want to squeeze more power out without big bore kit and where would you recommend getting this done i live in Norfolk



  • You won't see any noticeable gains from boring the DT barrel mate.

    The way to get more power is either a Resleeve with a biggerbore. So the old sleeve pressed out. The bore taken out and plated, or a new sleeve with bigger dimensions. The question then is can you find a piston that will fit the bigger bore.

    The Athena kit, or equivalent.

    Or just go old fashion tuning.

    The last one is the one to go for if you asked me.

    Stuff like, cleaning up the ports, bigger carbs.

    My favourite and best bang for buck alteration is the Zeeltronic Ignition system. Radically transforms the whole RPM range.

    Then theres a decent underslung pipe.

    Lighter flywheels.

    Lighter bike in general.



  • @jimmydc98 I've just had my spare DTR cylinder bored out to 58.40mm but have yet to install it so can't comment on performance but I believe 58.80mm is as far as you can go I've not seen Pistons over that size for the DTR .



  • @Biker_123 said in max bore on dtr:

    @jimmydc98 I've just had my spare DTR cylinder bored out to 58.40mm but have yet to install it so can't comment on performance but I believe 58.80mm is as far as you can go I've not seen Pistons over that size for the DTR .

    You need to modify the powervalve if you take it out.



  • where can i get it done though as it need a bore



  • @jimmydc98 PJME do it or if you search dt125 rebore on eBay there's a few offering the service! I got my local motorcycle garage to do it and I supplied the piston and gave them the cylinder,piston and they done the rest. Remember to leave the power valve in the cyclinder when getting it rebored like Callum says as it needs machined down to stop the piston catching it .



  • @Biker_123 I wouldn't leave the powervalve in since they will charge you to remove it.

    Modifying the valve is a trivial task you can do at home.


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    The worst mistake I made was leaving my power valve in my cylinder when I sent it to a Yamaha dealer. Without asking they removed and modified it and the labour charge for it was ridiculous. I think about £90.



  • I guess so that's a good point that I forgot about my place didn't charge for removing it and machining it down or whatever they had to do to it but if you can do it at home that's the way to go .



  • How would I go about that then is there any videos or anything