Kawasaki F9 Bighorn project

[John Conroy]

It's been over a year since I finished my last bike project and I have been feeling like taking on another one lately. I picked up a running 1972 F9 along with a non running parts bike at the Red Deer swap meet a few years ago so hopefulky I wont break the bank buying parts for this one. It will need a new chain and sprockets but I have not been able to find reasonably priced sprockets in the original ratio so I decided to make sprockets using common weld-on ones available at Princess Auto. I picked a 42 tooth and a 13 tooth to match the originals as closely as possible. They fit common agricultural 50 chain but will also fit 530 motorcycle chain. On the 42 tooth rear I bored the center hole to 47mm and drilled six 10.5mm bolt holes on a 104.5mm bolt circle. Then I added six 34mm holes on a 146mm bolt circle to match the look of the original sprocket. My plan is to strip the black finish and zinc plate the new sprocket. Here are a few pics of the process.

The first pic shows a 47 tooth and a 41 tooth from the 2 bikes I have along with the original 13 tooth front and the 2 weld on sprockets from PA.

It fits the wheel hub with the 47mm hole bored.

$25 for the weld on sprocket and a few hours of quality shop time.

 

[John Conroy]

For the front 13 tooth sprocket I re-used the splined center of the original worn out sprocket. I cut off the teeth with a disc grinder. Then I machined an arbor to fit the ID of the splines and with the old sprocket center bolted to the arbor turned the OD of the center of the old sprocket to 1.626" to give a .001" interferance fit into the 1.625" bore of the weld on sprocket. With the 2 pieces pressed together I TIG welded them together.

 

[YYCHM]

With all of this going on, how come your shop looks so clean?

Amazing craftsmanship by the way. Makes me feel like Bubba LOL.

 

[CalgaryPT]

So nice.

Your shop looks too clean though. Please fix that.

 

[John Conroy]

Thanks guys. I have so much stuff jammed in my little 1/2 of the double garage that I can't let it get cluttered. Pretty much everything is on wheels so the floor has to be swept before anything can be moved. I just did a major clean up last week to make room for the new sandblaster.

 

[PeterT]

That a neat way of gripping the gear plate. Kind of a dog action on the tooth. Did you make threaded pins that replace a bolt in the jaw screw hole, or what am I seeing here?

 

[John Conroy]

I just use 5/8" pins fit into the root of the teeth to keep the sprocket centered in the chuck and prevent damaging the tips of the teeth with the chuck jaws. Since the number of teeth on that sprocket is divisable by 4 that works in the 4 jaw chuck. I don't have a 4 jaw for my super spacer so I used flat plates to span the gap between 2 teeth at each of the 3 jaws and keep the sprocket centered in the chuck as well as spread the chuck jaw force over 6 teeth instead of 3. It can be a hassle working on a sprocket with odd number of teeth that doesn't divide by 3 or 4, 41 for example.