Bought a well used '95 300 fourtrax a couple years ago. It has been burning some oil at start up so decided to try to do a valve seal job on it. So one of the long 10mm bolts broke clean off down in the head. Wondering if I have any other reasonable options other than taking it to a machine shop to dig out the broken threaded part? I think someone has done this job at some time in the past and they probably used thread lock on some of the bolts. A couple other bolts were also very tight but did not break. Any help would be appreciated!