Define 'a few km'.  I ask cause some noobs think anything over 10k means the bike is for the scrap heap

more compression is why.

I got 30 degree pistons made to order from JE just had heads machined to match as Cow at L A Cycles told me long before i saw Hammer using that, the 30 degree chamber helps flow as well as i got a really clean burn. but Hammer sell you barrels. might be ok if you have 883, but if i had the feel of my bike & could ride it at track & use every horse i had. and just got JE pistons 30 degree got heads machined to match in my 1200 you got the hammer kit 1250 . and we went to the track and you could use every horse you had too. would be nothing in it. if we did not miss a shift LOL. just saying this as have raced and seen myself. the track is an eye opener.