Finally getting around to changing the timing belt on my 1994 ST1100. Changing the tensioner and spring as part of the project. All went well until I broke loose the tensioner bolt. Thought when it broke loose it was just the factory thread lock giving way. But it continued to turn hard instead of freely. Backed out about a turn and a half, then decided I'd tighten it back up, maybe extra stubborn thread lock. It did not want to move. So my only choice was to continue taking it out, not an easy task. Turns out the first five threads of the bolt furthest into the engine were filled with aluminum casting. Seems the aluminum casting on that end of the bolt welded itself to the bolt. Instead of the bolt unscrewing from the threads, the threads just broke off. Could not even clean aluminum from the bolt threads after bolt removed. Had to use a 10 X 1.25 die to cut the aluminum from the threads. In the course of removing the bolt, aluminum welded to the bolt end threads pretty much destroyed remaining threads in the engine casting. Ran a 10 x 1.25 tap through to clean up the damage. Guessing less than 1/2 the thread depth is left. After a little bit of investigation found there is about 1/2 inch of unused thread behind where tighten bolt would stop. Bolt screws in about 3/4 inch, total threaded depth in casting about 1-1/2 inches. Which option would you folks take.
1. Since 1/2 inch of unused thread left in the engine casting, just buy a bolt 1/2 inch longer than stock bolt, reach those unused threads and call it good.
2. Bore it out 3/4 inch depth and seat a 10 x 1.25 helicoil and use stock bolt. Wish they made helicoils in one inch or longer lengths instead of just 1/2 inch.
Maybe someone out there has something that would work better that I don't know about.
Have heard of this problem with dissimilar metals bonding together happening, but have never run into it before. I am posting this just as we are leaving for three days, so Thank You for your responses in advance.
1. Since 1/2 inch of unused thread left in the engine casting, just buy a bolt 1/2 inch longer than stock bolt, reach those unused threads and call it good.
2. Bore it out 3/4 inch depth and seat a 10 x 1.25 helicoil and use stock bolt. Wish they made helicoils in one inch or longer lengths instead of just 1/2 inch.
Maybe someone out there has something that would work better that I don't know about.
Have heard of this problem with dissimilar metals bonding together happening, but have never run into it before. I am posting this just as we are leaving for three days, so Thank You for your responses in advance.