I had drilled the swinging arm of my '11 990 Adventure Dakar when it was new so I wasn't sure if it really did any good or not . I sold that and picked up '10 990 SM-T recently that had 17000 on the clock. I noticed that the swinging arm was not drilled so I drilled both sides. I was amazed by the amount of water that drained out.
If it was not drilled the chain adjuster bolts are probly trashed , I bought a SE a few years ago and the po had not drilled the drains and had also put zipti axle blocks on it . That was a major pia , close to 8 hours . I ended up stripping the threads trying to get the pos aftermarket crap out and helicoiling new threads . Replaced the blocks back to original and lots of antisize . At least it was correct when I sold it .
I pull the bolts and grease them with moly-grease at every new chain/sprockets. Also, several times when I change a tire.
I had the bolts seize on my 08 990 around 2015. I drilled drain holes as advised from fellows on Advrider and applied antisieze after a struggle to remove the stock bolts. Changed out the tires recently and made sure I screwed in and out the bolts in question. All is good:) Thanks fellows it is good to have camaraderie keeping the 990 on the road. On the TAT, crossing a desert Playa, Utah Nevada border... Yep had to remove the fender to continue.
