Timbone
Well-Known Member
Well, I broke the motor mount on my GTA-2 pre built aluminum frame. This is complicated by the fact that I have already broken one of the four 6mm motor studs: the one on the rear left. I have successfully dealt with this problem, using a wooden block and metal strapping to hold the back of the motor tight. Still, with hundreds of miles of riding, the smallest front to back spring was enough to break the weld on the mount over time.
With cold weather having moved in, it's a good time for experimenting. I'll be buying a new motor soon, so I can't really go wrong.
I did a LOT of thinking to come up with a fix. I bought two thick angle pieces made of thick steel (at least 12g). I cut them so they would make two "L" shapes, using the first "L" to affix to the downtube and resting on the now useless cross member that used to hold up the old aluminum motor mount. I used a 5/16" U-bolt to hold that part on. I inverted the other "L" and affixed it to the first "L" with 4 3/8" bolts. Threadlocked it and it is beefy! It would take a nuke to bust this thing up! I affixed the inverted "L" to the motor with 5/16"Grade 8 bolts and nuts.
Grabbing the back of the engine is my big problem. My plan is to JAM the engine into a position that nothing can move. I actually had to start with this end.
I am using two thick stainless steel couplings as spacers. On the right side, with the stud in good shape, I used a bolt and made a kind of cylinder with a tight packing of small washers that squeezed one side of the stainless couple/spacer. The other coupling was filled with 6mm washers that I glued together inside the coupling to make it all easier to handle and to fit up. These two spacers are basically jammed into the bottom rear of the engine, and held together by a 1/4"-20 U-bolt. The U-bolt is not as tight as I would like, but the left shaft feeds up and into the very tight spacer rig (an inner cylinder of washers) and really has no where to go. The right shaft of the U-bolt rides far into the coupling/spacer and won't allow it to move.
The final step was to attach the motor to the seat tube with carefully measured muffler strapping. As of right now, the motor is tight and cannot move! I'll have to do some extensive testing when it gets a bit warmer.
The good news in this is that the motor moved slightly forward giving me the ability to take all the slack out of the drive chain. That's it! The Holy Grail of Motorbiking! No need for a chain tensioner. Now all I gotta do is tighten up the pedal chain and adjust the fuel line to optimum length.
I'll post photos if anyone asks.
=Timbone=
With cold weather having moved in, it's a good time for experimenting. I'll be buying a new motor soon, so I can't really go wrong.
I did a LOT of thinking to come up with a fix. I bought two thick angle pieces made of thick steel (at least 12g). I cut them so they would make two "L" shapes, using the first "L" to affix to the downtube and resting on the now useless cross member that used to hold up the old aluminum motor mount. I used a 5/16" U-bolt to hold that part on. I inverted the other "L" and affixed it to the first "L" with 4 3/8" bolts. Threadlocked it and it is beefy! It would take a nuke to bust this thing up! I affixed the inverted "L" to the motor with 5/16"Grade 8 bolts and nuts.
Grabbing the back of the engine is my big problem. My plan is to JAM the engine into a position that nothing can move. I actually had to start with this end.
I am using two thick stainless steel couplings as spacers. On the right side, with the stud in good shape, I used a bolt and made a kind of cylinder with a tight packing of small washers that squeezed one side of the stainless couple/spacer. The other coupling was filled with 6mm washers that I glued together inside the coupling to make it all easier to handle and to fit up. These two spacers are basically jammed into the bottom rear of the engine, and held together by a 1/4"-20 U-bolt. The U-bolt is not as tight as I would like, but the left shaft feeds up and into the very tight spacer rig (an inner cylinder of washers) and really has no where to go. The right shaft of the U-bolt rides far into the coupling/spacer and won't allow it to move.
The final step was to attach the motor to the seat tube with carefully measured muffler strapping. As of right now, the motor is tight and cannot move! I'll have to do some extensive testing when it gets a bit warmer.
The good news in this is that the motor moved slightly forward giving me the ability to take all the slack out of the drive chain. That's it! The Holy Grail of Motorbiking! No need for a chain tensioner. Now all I gotta do is tighten up the pedal chain and adjust the fuel line to optimum length.
I'll post photos if anyone asks.
=Timbone=
