Hell On (Two) Wheels 7 – Gearing Up

Hell On (Two) Wheels 7 – Gearing Up

In today’s edition of Hell On (Two) Wheels, we move from the exhaust over to the drivetrain.

Part of the new wide rear end on the Vulcan, if you noticed, was a large sprocket for the rear axle that functions as both the chain drive sprocket as well as the rear brake rotor. That being said, the Kawasaki Vulcan 2000 Classic is a belt-driven bike from the factory. Obviously, something needed to change, and that something was the belt. It has been discarded (along with its driveline pulleys) in favor of a chain-driven setup. Getting the sprocket made resulted in us receiving two parts — the sprocket ring itself, the toothed part that touches the chain; and also, the blank barrel that connects to the driveshaft splines.


Seeing as how these splines are of a design that differs even from other bikes in the Vulcan lineup, custom was the route to take with this part. Upon receiving the pieces back, we test-fit the main barrel to make sure it matched up to the driveshaft splines. It slid on perfectly, without even so much as a hint of free play. We also took to measuring the barrel to ensure that it was perfectly round, as we were told it would be. And it was well within spec, so everything’s checking out perfectly thus far.


Now, everything came in two distinct pieces for a reason — precision fitting. Without the bike there, the man making the sprocket would have no idea where to put it in relation to the rest of the barrel and the bike as a whole. For that reason, the barrel was given to us without welds, only being press-fitted together. The same will have to happen for the toothed sprocket ring; it will need to be pressed on to the barrel and then welded into place. After pressing the sprocket teeth onto the barrel in the desired location and mounting up the barrel to the bike, we tack-welded the sprocket teeth in place.


With everything where it needs to be in terms of fitment, we took the partially-finished chain sprocket assembly over to the welding table, where we filled in both the barrel itself (consisting of an inner and outer segment) and the sprocket teeth. Now, even though the metal is much thicker than what we normally weld, we have to take heat-based warping into account. Given that, we only weld small segments of the part at a time, allowing it to cool in the interim so it moves away from the point where it becomes slightly malleable. Seeing as how we didn’t hover in fab during this process, we’ll share some results from towards the end of our welding adventure.


With everything welded up and subsequently cooled down, we took the mostly-completed sprocket assembly to the lathe for its final adjustment — the removal of the excess barrel. We only need the sprocket to go up to the teeth — anything past that is just extra weight that parasitically draws power from the driveline. So, for that reason, we started rotating it slowly and cutting precisely where we needed to. Thankfully, this part of the procedure gave us several wonderful pictures to work with.


And here’s what resulted. Yes, it’s a little rough, but we’ll address that…


…By polishing it up and mounting it back in place. Much better. And now the bike will be able to move; which, according to most experts, is a good thing.


Thankfully, we won’t have to take additional aesthetic steps to pretty up the sprocket even more — seeing as how it’s a serious moving part that could spell trouble if it snags an accidental shoelace or pant leg, it’s been designed to hide within the OEM Vulcan sprocket shroud. We’d give you a picture, but it would spoil what we’ve got lined up for our next post. So, with today’s chapter closed, it’s time to get back to work!

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