Seems like the new case still does not fix the cracking crankcase problem... mine cracked at the mounting tab... I really love this engine but really???

Does anyone know if the internals can be put into the ninja jx21 bo1a?? My case has also cracked in the same spot

Yes they can.

We have been running these engines for a while in stock and. Modded form. Never had a block crack on the newer engines. We do have few os blocked with arrow internal and carbs modded. Assuming pretty much any vzb based block will do the trick. But we have seen a higher performance in an old vzb speed block over the others. Could be the fastest one yet.

this is a really good engine!!!!!

Do you use the OS crank and carb?

Atom Vortex .21- Any one run this motor yet? I have a speed ii vzb that had a screw break off holding the head button. Looking at using this case for the internals? New OS crankcase is 109 at tower. When I could get a hole engine for a few dollars more.