the 2003 was easy to derestrict the standard 3rm-20 cdi I actually found very good. Restrictions were the standard exhaust and the reed switch in the back of the speedometer. They came with the powervalve from factory unlike some other years which I can't believe they did fit servos! Back when mine was 125cc it would destroy an 1990 DTR
@sgt-robuck-5 Don't forget the ignitech @Darty rates them.
I used Zeel because it came recommended to me.
I will be buying zeel for my upcoming project.
I've had problems with them, I contacted them and they sorted it out no quibbles.
Peace of mind.
Oh dear, back on topic anyhow....Let us know how you get on with the PV. If it still struggling then it would sound like it's still restricted and needs sorting ASAP! 2003 models were the WORST for restrictions!
2strokes in general is jetted plenty rich, to make sure they dont seize.
I run my 94 R with snorkel removed, and the airbox opened slightly more.
Stock mainjet, and half a notch leaner on the needle. The mainjet is still plenty rich.
Stock header, and aftermarked end can, otherwise stock.
You shouldn't be polishing either really,
but here is a used MITAKA vs a New WOSSNER to illustrate. Carbon does help to a point. The Wossner is a CNC finish, but if your hunting power there wont be any difference.
Problem with forged is the difference in thermal expansion to a cast alloy. MITAKA is a good choice for the DT.
Smooth yes, but a rough surface lends itself to optimising fuel atomisation, that is more important.