They can be stuck tight. One should oil the threads on assembly. FWIW I have not had a great time with snap off torx bits. I got tired of them doing just that. I got a set of TENG ones , on advice of a tool rep and have had them for ages with good results.
I left half a torx bit in my Sprint taking the heads off for someone that wanted them, I didn't pursue it and further, scrapped the engine, crank was broken.
Sonny they make a plus size in the torx and this may be what the head bolt is
TP55 carlyle socket napa part number CHT S38TP55 $11.99
or u can search the net for tp55 or torx plus
hth
It does seem contradictory that the cheap Chinese bits are good, I have certainly found that. Also had the same issue with my speed triple , bugger snapped off and stuck inside the bolt head. Having the upper body strength of Calista Flockhart doesn't help getting the rocket head bolts undone either.
some of the gm transmission have that and we fight to get them off.
inpac driver, heat and sometimes team up on it with cheater bar and the air hammer with dull point.
Im definitely gonna heat these bolts before cracking on em, its cold in my basement garage. 55ish, im thinking definitely advantageous to remove head while in bike for torque pressure and engine not trying to move on ground, i have to split to get my trans off to robinson industry for the race cut service for street/strip, not the race only version thats next . does this sound ok guys head off, then engine out, then split case?
some of the gm transmission have that and we fight to get them off.
inpac driver, heat and sometimes team up on it with cheater bar and the air hammer with dull point.