Those OWB's are high quality, it's not the roto starts fault. It's HPI's fault for failing to put instructions in the engine manual for a proper breakin without breakage. A new engine at ambient temperature plus rich needle settings =broken OWB's.
To prevent this, preheat your engine for the first 8 tanks or so. Loosen the glow plug a little to relieve the strain on the bearing.
HPi will tell you it's user error, which is true. BUT they do not tell you the proper way!
You switch to pullstart and you'll be carrying home a non-running truck in one hand and a broken pullstart in the other. Roto is the best starting method except for starterboxes. Can't use those on a Savage though.Good strong batts help too, the faster it spins, the easier it starts.
Follow my advice and your OWB's will last 3-4 gallons easily.