Possible to bore out a 2005 SX125 cylinder from 54mm to 58mm (144cc)?

Hello guys!

 

I have a question regarding my KTM SX 125 2005. I have been rebuilding my bike during the summer, and now it is time to rebuild the engine before the upcoming season. I just came off a YZ250 which I needed to sell because of the arm ripping power. Going down to 125 is much more fun, but I kinda miss some of the instant power I had on the 250. Therefore, my question is if it is possible to bore out my 125 to 144? I have used Eric Gorr before on a YZ85->YZ105 with good experiences. One thing I am unsure about is if the cylinder skirts are big enough to accept the bigger bore and also if there is any potential to increase power. To those of you saying that I just should buy a KTM 150, this is not an option. I really like my old thing and want to use it since it has rebuilt racetech suspension fitted for a person just my weight (approx 190 lbs / 90 kg geared up).

 

Anyone with any experiences?

 

Greetings from Norway,

Sindre

Edited by sindre_a

First post, welcome! Unfortunately I'm not 100% sure, but I don't believe the cylinder has enough wall to bore. Maybe someone else with more knowledge on the subject will chime in, you might be stuck using bolt on products to increase the performance of your bike.

I had an 03 125sx previous to my 150, that 125 was one of the fastest I've ridden, not sure what the engine changes were between the 03 and 05? Mine had Vforce 3 and a Pro Circuit pipe and r-304 set up, fun bike to ride, should have kept that one...

Revalve your suspension first and then worry about the motor. I know this sounds rediculous but trust me it makes a huge difference

Revalve your suspension first and then worry about the motor. I know this sounds rediculous but trust me it makes a huge difference

 

If you read my post you will find out that I have had my suspension rebuilt with race tech components after my weight and riding style.

Edited by sindre_a

Not sure if they still do it, but Langston Racing used to do just what you are asking about. No info on their website about it, but call them and they may be able to help you. langstonracing.com

I have tried to reach them by mail, but they have not reaponded yet..

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