NC30 Lower Engine Mount Seized
Posted: Mon Feb 06, 2012 6:32 pm
Hey guys, I'm in the middle of a rebuild. I recently bought a replacement engine as my existing one has a really whiney first gear and I wanted to rebuild it, so I bought a replacement as a stop gap so I wasn't off the road for too long.
I've taken all ancilleries off of the engine, unbolted the radiators, carbs, exhaust, front sprocket, etc. I'm basically left with a swingarm, frame, forks and engine. All the other bolts have undone with no problems. The lower engine bolt, however, has been a right troublemaker. So far, I've undone the locknut with the special Honda castellated socket Rick O sells, and undone the M12 (?) nut from the left hand side. All attempts to undo the bolt that goes through the frame and engine, and the slotted M20ish bolt that surrounds it, have been futile.
We started by soaking the whole lot in GT-85 and then trying to turn it with a 6mm allen key. That quickly rounded off. So then we knocked a T40 torx bit into the head and tried turning that with a socket. That didn't round off, but we did manage to twist the splines on the torx bit. Either way, the bike still laughed at me. Next we broke out the paint stripping gun and tickled the bolt at around 500 degrees C. Still nothing. More heat and then a bit of persuasion with a punch and a hammer from the other end. Still nothing. I'm starting to run out of ideas.
We thought about possibly trying a blow torch, and another friend suggested the possibility of using two nuts on the left hand end and undoing it like you would an exhaust stud. I've already bought a replacement bolt, so it's really just a case of getting the existing one out by any means neccessary. Obviously, I'm concerned about writing the frame or engine off, which is why I'm wary about using a blow torch.
Has anybody come across this before? Any ingeniously little tips that makes this all a doddle? Or should I just use a bigger hammer?
I've taken all ancilleries off of the engine, unbolted the radiators, carbs, exhaust, front sprocket, etc. I'm basically left with a swingarm, frame, forks and engine. All the other bolts have undone with no problems. The lower engine bolt, however, has been a right troublemaker. So far, I've undone the locknut with the special Honda castellated socket Rick O sells, and undone the M12 (?) nut from the left hand side. All attempts to undo the bolt that goes through the frame and engine, and the slotted M20ish bolt that surrounds it, have been futile.
We started by soaking the whole lot in GT-85 and then trying to turn it with a 6mm allen key. That quickly rounded off. So then we knocked a T40 torx bit into the head and tried turning that with a socket. That didn't round off, but we did manage to twist the splines on the torx bit. Either way, the bike still laughed at me. Next we broke out the paint stripping gun and tickled the bolt at around 500 degrees C. Still nothing. More heat and then a bit of persuasion with a punch and a hammer from the other end. Still nothing. I'm starting to run out of ideas.
We thought about possibly trying a blow torch, and another friend suggested the possibility of using two nuts on the left hand end and undoing it like you would an exhaust stud. I've already bought a replacement bolt, so it's really just a case of getting the existing one out by any means neccessary. Obviously, I'm concerned about writing the frame or engine off, which is why I'm wary about using a blow torch.
Has anybody come across this before? Any ingeniously little tips that makes this all a doddle? Or should I just use a bigger hammer?
