Does anyone make a big bore kit for the Yamaha XT 225?

Discussion in 'Thumpers' started by Ross Foy, May 8, 2008.

  1. Ross Foy

    Ross Foy Been here awhile

    Jan 30, 2008
    Have a Yamaha XT 225 that needs some engine work, but overall is in good condition. Was thinking of adding a big bore kit to up the power if the price is right. Does anyone know of a good one on the market?
  2. Cigar Mike

    Cigar Mike Too Old and Too Slow

    Jan 16, 2007
    Centennial, Co
  3. montesa_vr

    montesa_vr Legend in his own mind

    Mar 24, 2006
    If you do a big bore kit, be sure to change your jetting. At the very least you will need a much fatter main jet to keep your new thirstier engine from running dangerously lean. A big bore kit with standard carburetor and exhaust will gain a lot of torque down low in the rev range and no noticeable difference on top. Might be just what you want.

    Big bore kits increase compression, which will probably force you to use premium gas. Changing the cam might give you more top end and slightly reduce your octane requirements (and reduce your new low end power at the same time). Or it might just be a big hassle to install and maintain.