I have a offer on a 12.5 piston for a standard bore. But I'm mechanically inclined but have never did any major repairs on the ds. How hard is it to change pistons. do I have to adjust the valves again or can I just pull the timing sprocket off and lift the complete head off with cams. Would keeping the stock cam and adding more compression be a good alaround combination for woods riding. maybe just getting a mild pport job.

 

i think that is a great way to go, and no you won't have to do any cam shiming with just a piston. the only thing is if you want to do a cam later and want heavier springs you will have to pull the head again. the over all job is easy the rotax engine is very friendly to work on, so easy that i actually enjoy it and mechanics isn't my favorite thing. the tricks are the intake manifold it takes a round end allen to get the top screw out and then there is a lot of info on what has to be done on tilting the engine forward and sliding the head off, some have to grind, i never have and it comes off great, but it isn't a big deal some are saying to remove that mount altogether. i have two ds's one is stock one is stage two and on the flats the stage really whips the other on the hills it is a lot closer, so for what you do the cams might be nice also.