Monday, September 10, 2012

Axles, spacers, brackets, more spacers...

Lots going on lately...

First of all, I'm still on track to have this thing rolling by the end of the summer. I've been working out the final design/shapes of all the rear-end parts for a while now and I'm finally done.
From my last blog entry where I posted that "drawing" of the rear axle plates, blocks, guides, etc...
I sent a digital file to Hydrocut Waterjet out in Hunnington Beach CA.
Check them out at:
www.hydrocutwaterjet.com
These guys are super professional and nice to work with. I'm definitely not "Joe-CAD-guy" and they treated me like I was. -AND they don't have a minimum order requirement! This is huge (to me anyway...)
So this little package of parts showed up on my doorstep on the Tuesday after Labor day!
What you're looking at here are the rear axle plates and axle block guides (both cut from .375 steel)
The funny looking silver things hanging of the back of each plate are the "swingarm lifters". These will be what the rear-stand hooks into to lift the rear end of the motorcycle off the ground and hold the bike steady (like a kick stand). These are .25" 6061-T6 aluminum.
Under the left plate, there's another silver thing... that's the bracket that holds the rear brake caliper. The axle passes through this bracket so when the chain gets adjusted/tightened the caliper moves with it and the wear surfaces on the rotor/pads stay consistent. -Not rocket science, as almost every bracket is this same design, but because I'm mixing/creating lots of different parts here, I had to redesign this whole layout.
For example, this caliper is from a 1990 Yamaha YZ250 dirt bike. Look and see where the caliper sits on the original bike... On the stock bike, it's about 1:00 to 2:00. On mine, it sits at High Noon.

Here's a loose fitment:
I machined the tops off the stainless bolts that are holding the swingarm lifters on... go figure. Also had to countersink the lifters so the bolts would sit flush. I love this stuff!

I put a braze joint around the outside of the axle block guide for stability (and for a nice, rounded joint between the 2 parts:
You can see the rear caliper bracket here too. This will be it's final position.
I guess looking at all these pics it may seem like there's not too much to the rear end, but I can definitely tell you that there is lots going on. I don't have any pics of the spacers, but in order to space out the axle plates evenly, there are spacers on either side of the hub that are different widths. Taking into consideration the distance between the frame tubing and the chain (don't want THAT to rub...) on the left side as well as spacing the rear caliper EXACTLY over the rotor and having enough "fore-aft" clearance so the caliper bracket doesn't touch the rear frame tubes... etc.

Easy if you're a fo-real motorcycle designer with an engineering degree and 3D CAD software... not so much if your name is Dan and you're using graphic design software to design this stuff...

Anyway, I'm not complaining. Every time I walk out to my design lab (garage) I still get excited just staring at this thing. Sometimes that's all I do... just think and stare. Some people may not get it, but from talking to my friend Jimmy up in IL, he does the same thing with the hot rods he builds. I guess I'm not the only weirdo.

The last thing I need to get done before I'm ready to attach all this stuff the the main frame is get the axle sorted.
The original Suzuki GN400 Axle is 20mm in diameter... The same as a 1990 YZ250 dirt bike. (which is where I got the rear hub/brake rotor/caliper/etc.) Lucky me. However, by utilizing a disc-brake rear wheel/hub instead of the stock GN400 drum brake, I need a little more length in the axle than the stocker. -Guess what other bike uses a 20mm axle? Yep... you guys are smart. A 1992 Honda CBR600. So, I got one.

Here is the difference between the stock Suzuki GN400 Rear Axle (on the bottom) and the '92 CBR600 Axle:
I just need to run the threads up to where I put the tape on the CBR axle. That'll be perfect.
My friend Jimmy who I mentioned earlier has family in Mooresville, NC that own a motorcycle shop called "Prism Motorcycle Co."
Check them out at:
http://prismmotorcycleco.bigcartel.com/
They'll be doing the thread-extending. Hopefully I'll get it back soon, then I can start connecting the pieces!

As always, thanks for reading!