just shot for a OS, replacement parts bearing, conrods, sleeve and piston, all are very reasonable and less expensive than nr

I just picked one up brand new from absolute hobbyz 190$ brand new. Absolute screamer, great top end with tons of low end grunt.

i saw that one. is this engine with NR's notorious odd side expensive bearing?

Spent half an hour trying to look up the specs for the rear bearing since you mentioned it. Either way if it is, you can usually go aftermarket with a bearing supplier without the crazy markup. Was able to put new bearings in my R2101 from boca for about 50$

A fellow driver is using a 15 dollar Trackstar bearing set (front and rear!) in his OS w/o any issues. OK, no ceramic but ceramics does not add a noticeable value to the performance.

Regarding the Keep on. Yes, it has the expensive bearing which is not listed anymore on the bearing list on the Novarossi site. But if you know someone with a lathe you can modifi the crankcase to fit normal 14.5x26 bearings.
Placing cheap "normal" bearings in a Virtus

Yeah ceramics are good for "look how fast my engine can rev!"
As a machinist, that seems like it'd be a small nightmare indicating the crankcase in

just wonder what is the difference with keep on and flash.21PT? the latter one has very cheap non NR bearing

For the .12 engines, the bearing was the only difference between the Keep-On and the Flash PT, making the Flash PT a much better buy.

Eh...I don't like how OS has specially designed parts for damn near every engine they make. Sharing parts is a good idea, that's why we invented mass-production in the first place.

WHAT ??? What are you trying to state or say?????