Jun 14, 2002
I am wondering what would be better/easier. I have a 2003 125sx, and know that the 200sx is the 125 with different cylinder and piston. Would it be easier and more reliable to just get a 200 cylinder? would it be easier to have eric work out a "normal" 125 bigbore? I was also looking into getting exc pistons, because they have 2 rings, and although they are hard to come by, I wouldnt mind a little less time in between rebuilds, I go about 20 hours (on my hour meter) between rings and go 40 hrs on a piston. I know of a 200sx for sale, but they want wayy to much for it, and I have a friend that has a 200exe and raves about it, that is what started this whole thing. I love this darn KTM, and am willing to try some new things. Any other suggestions?? I just put a new topend in it 20 hrs ago, and did a rod about 30 hours ago. I LOVE THIS BIKE!!


Jeff Gilbert

N. Texas SP
Oct 20, 2000
I had this mod. If you want to use the 200 piston & cylinder on the 125, you'll have to change the rod too. It will become a 174. Overall the bike rips but it made it a little hard for me to ride. The throttle response was like a toggle switch. The power delivery was so intense that I got more wheel spin than traction. You will want to regear it too. I bought an 07 250sxf and sold the 125/174.


Aug 13, 2000
I could have sworn the 200 had a longer stroke. If so, using a 200 cyl on a 125 would result in unusual power issues.

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