REMOVING TROUBLESOME FINAL DRIVE FILLER CAP

[Granpah]

I decided as part of my winter maintenance to replace the final drive oil which hasn't been done since I bought my bike two years ago.

Problem: The final drive filler cap which used to be a 17 mm hexagon is now a 16 mm pentagon. Someone who didn't know that 17 mm hex sockets and wrenches exist chewed off one of the points while nearly rounding the others. I've ordered a replacement from CheapCycleParts.com (about $8 plus $3 for the O-ring). I've tried the obvious (forcing a 17 mm wrench, and then power grip wrench -- while trying to avoid further damaging the filler cap. It didn't budge.

Surely someone else has had this or a similar problem. So what is the "easy" way of getting a chewed up filler cap out and not destroying either what's on inside or the outside of the final drive compartment.

I had thought of drilling through the cap and then using a bolt extractor for removing it. But I worried about metal shavings getting into the final drive housing and damaging the gears, etc.

What to do? hock: :-SS B-(