Replacing a 17-year-old Critical Component
From the time I'd bought my Hawk, regular discussion took place on the Hawk-list regarding the importance of replacing the cush-drive. These five rubber spacers act like a damper between the rear sprocket and the rear wheel and are critical to suppress harsh jolts traveling between the motor and the rear wheel. Slam on the throttle and the cush drive prevents damage by absorbing a portion of the abrupt energy.
On traditional bikes, every time you pull the rear wheel the sprocket falls off and the little rubber dampers bounce all over the garage, facilitating easy inspection. But on the single-sided-swing arm Hawk, the cush-drive rubber dampers lie hidden somewhere within the mysterious confines of the rear hub. By the time urgency overcame me these rubber dampers, critical at protecting the final drive of my little Hawk, were over 17-years old. Other Hawk-listers had reported opening their Hawk-hubs to discover the cush drive rubbers had been reduced to a chalky powder.
With five fresh dampers and my Hawk shop manual in hand, I was ready to open the mysteries of the elf-designed, single sided swingarm.
The first obstacle is the massive rear nut. Located on the left side of the bike, this nut is "staked". Meaning that a section of the nut has been mashed down into a recess in the axle. The manual simply says, de-stake the axle nut. Okay, then.
Not knowing exactly what this required, I used a very precise, specialized tool to perform this delicate procedure. A small flat-head screwdriver and a hammer. A few careful smacks with my ball-peen and the axle nut was no longer staked.
Fortunately for me, the axle nut is the exact same size as the axle nut on the Speed Triple; 46mm. A breaker bar was all that was needed to spin the nut off the axle. From what I understand a more common 1&13/16 should also fit.
Removing the axle nut, and the lock washer is not enough to release the hub from the swingarm. (there is also a third, thick spacer that centers the hub on the axle - not pictured). The chain prevents the hub from sliding off the axle. Even after loosening the chain all the way, the hub would not clear the axle. I decided that pulling the sprocket would be the simplest solution.
Only six bolts stand in the way. Once the sprocket is separated from the hub, the hub should slide right off the splined axle.
I was surprised by the simplicity of the design. But baffled on how to separate the obvious two pieces of the sprocket carrier/hub. Behind the sprocket carrier, the eccentric chain adjuster can be seen for its simple, yet brilliant design. It's all making more sense!
After a few minutes of fiddling, and having no luck at separating the two parts, I very gently tapped the carrier onto the floor. It popped apart, straight-away, revealing the green rubber cush drive parts to be replaced. While I was delighted to learn that my cush-drive rubbers had not been reduced to dust, they were rock-hard and had turned from the green color they started life as, to a distinct aluminum color.
The new cush-drive parts (Honda part number 41241-MN8-003) did not have the dashing aluminum staining and were much softer and more pliable. They are shaped to go in a proper way and a wrong way. The tapered end, (facing the top in the picture) should face the bottom of bowl shaped half of the carrier. Also, the cush rubbers are connected by a little strap. Do not break the strap! The strap is designed to sit on top of the ribs to help hold the cush rubbers in place.
Look how nice and happy those new cush drives look. Once installed, I sprayed them down with a light coating of WD-40 (I hope this is okay) and slid the two halves together. I tried to put the pieces together without a slippery catalyst, but the traction of the rubber cush-drive bits would not allow it.
Before putting the carrier back onto the axle and buttoning the whole thing back together, I thought back to my old ST1100. The shaft drive splines were known for disintegrating if high pressure moly grease was not used every time the wheel was removed. What could it hurt to do the same to my Hawk. I put a thin coating over the axle splines, then put a thin coating over the female splines at the center of the carrier.
The rear nut is to be torqued down to 120ft.lbs. and re-staked. Don't skip this step as this is the bolt that holds the rear wheel together. This whole job took about one hour to perform. After it was complete, and riding it for a bit, surprisingly, I noticed a slight difference. With the old, hard cush drive rubbers in place, there was a bit of slop in the rear end. After installing the new cush drive, the entire drive system of the bike smoothed out, including shifting! Whoda thunk?