I decided that I wanted to change the (rather antique style) grips on my SR500 for something more comfortable.
I'm pretty happy with them but unlike the older styles, the ends are "uncovered" on modern grips. This left me the task of attaching end covers for aesthetic and functional reasons. I ended up selecting these:
as (before I'd taken the grips off) I figured they'd be suitable no matter what I found (empty hollow bar end or filled in with something. As it turns out the Yamaha bars had solid steel rod inserted into the bar to assist with damping vibrations. So I had to drill and tap a thread into this.
This task was done by:
- carefully identifying the center and then marking that with a center punch
- drilling a small pilot hole (that was straight and con-centric to the bars)
- successively drilling this out to the final diameter needed for the thread cutting tool
- cutting that thread (there's a technique)
- shortening the supplied bolt
- screwing it in and using light grade thread locker on that
- turning gently (two fingers)
- only turning till it bound
- back off at least one, sometimes two turns to feel for the 'break' of the cutting tool swarf
- backing all the way out to double check the measurements of drill depth
- knowing how far I'd been able to turn the cutting tool into the newly cut thread...
Of course now I haven't fucking got a cover on that side because when you break these off in there, there's just no drilling it out ...
On the place it broke, I'd felt that while the screws had enough thread I did not test that on the many occasions I'd backed out. I should have been doing this to be clear exactly how many turns of thread the cover mounting screw had (and it only needs a few right!!).
Had I done that I may well have saved this issue, had a good looking bar end on the right and maybe just more loctite on that one ... FCK
This is as much a warning to others as an exercise in accident analysis and self punishment
FCK!
