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Author Topic: CB450 Tracker  (Read 280 times)

Offline Pete12

  • Posts: 4
CB450 Tracker
« on: Oct 17, 2017, 10:06:22 »
Long time lurker, first time poster...

Picked up a CB450 from a mate for free with the idea of turning it into a street tracker. I built an RD350 racer last year that turned out OK, so this is being built for my brother. His only request was that it be fitted with pillion footrests and a long enough seat to fit his girlfriend's behind on behind...

https://i.imgur.com/HhKoLA0.jpg[/img]]

It was pretty weathered externally, but turned over freely with good compression.

https://i.imgur.com/lwiwtJN.jpg[/img]]

The outer covers were a bit knocked around so we found another CB450 on Gumtree for $210 that was incomplete and had been seized at some stage. The frame was in good condition so we decided to use that and keep the other one complete for the mock-up stage.

I had a set of YZ250 Excel hubs that I bought for my race bike years ago, so they have been donated to the project. I ordered 19"x2.75" Sun rims and S/S spoke from Buchanan's and laced them onto the hubs...

https://i.imgur.com/q98Cbx8.jpg[/img]]

https://i.imgur.com/xxGXl3v.jpg[/img]]

..and fitted them up with some DOT approved Shinko flat track tyres.

https://i.imgur.com/y3Z4T5n.jpg[/img]]

I started the frame mods by pulling the steering head back a couple of degrees to 25 to give it a tracker stance.

https://i.imgur.com/WBB02j3.jpg[/img]]

Obviously the bigger diameter wheels and pulling the steering head back has affected the trail and the wheelbase, so I plotted it out on AutoCAD to work out the new values for swinging arm length and fork offset. I made a new square section swinging arm that will bring the wheelbase to 55"-56". It still needs to be gusseted at the front and the shock mounts installed but it is OK for the mock-up.

https://i.imgur.com/HHxYYCV.jpg[/img]]

I also made all the hardware for the back wheel adjusters but still have to make an axle for it.

https://i.imgur.com/GDMEZAb.jpg[/img]]

I ordered a big hunk of 6160 aluminium that arrived a couple of days ago so I will start making the triple trees tomorrow night.

Please excuse the photo's, they are a mix of camera and phone and I have had a hell of a time trying to post them on here, so I will try and correct that for any future shots.

Offline Rat_ranger

  • Posts: 131
Re: CB450 Tracker
« Reply #1 on: Oct 17, 2017, 10:30:09 »
Good start, I'll be watching this to see how it ends up.
Xs650

Offline Pete12

  • Posts: 4
Re: CB450 Tracker
« Reply #2 on: Oct 18, 2017, 07:05:48 »
Made some progress today. I finished making the back axle out of 4140, but still need to mill a couple of flats on the end for the wrench. I have a really old indexing head that weighs a ton, so I'll wait until I have a few jobs to do before I wrestle it up onto the mill bed.

https://i.imgur.com/jyPMwG9.jpg[/img]]

Started boring the holes for the triple trees on the mill,

https://i.imgur.com/V0qbOky.jpg[/img]]

got them to size and then cut the bar in half (which turned out to be a big job), and tried them for size - all good. I'll set them back up in the mill and finish the thickness, profile, slots and retaining screw holes.

https://i.imgur.com/0Z4GEcZ.jpg[/img]]

I'm using the original CB450 stem with All Balls tapered roller races, just have to make a threaded insert and weld it in the top as I will make a S/S bolt instead of using the existing chrome nut. I'm giving it 0.0015" of interference so that it fits up nice and tight with the aid of my press and judicious application of heat.

After looking for a long time I picked up a perfect set of R6 forks from eBay for $150, pretty happy about that. They came with an axle which I will be able to modify to suit the YZ wheel.

I'm still trying to decide whether to use an R6 or YZ caliper on the front. The rear will be YZ and in the interests of uniformity, I will probably use the YZ one. Either way I have to make up fork or disc adaptors, so that's not really a deciding factor. The bike will be considerably lighter than it was from the factory, and I don't plan on doing anything to the motor aside from a rebuild, Mikuni carbs and a free flowing exhaust, so it shouldn't be too hard to pull up. I'd appreciate any thoughts on why I should pick one over the other.


Offline Rat_ranger

  • Posts: 131
Re: CB450 Tracker
« Reply #3 on: Oct 18, 2017, 09:36:51 »
Make an adapter for a 320mm rotor and use the r6 caliper.  Reasoning: supermoto guys upgrade to a larger rotor and 4 pot calipers to improve brake feel and fade.  Although if you already have the yz caliper it would do fine, just might not "feel" as good, which is subjective.
Xs650

Offline Pete12

  • Posts: 4
Re: CB450 Tracker
« Reply #4 on: Oct 18, 2017, 17:17:38 »
Make an adapter for a 320mm rotor and use the r6 caliper.  Reasoning: supermoto guys upgrade to a larger rotor and 4 pot calipers to improve brake feel and fade.  Although if you already have the yz caliper it would do fine, just might not "feel" as good, which is subjective.

Good advice, thank you.


Offline canyoncarver

  • DTT SUPPORTER
  • *
  • Posts: 3027
  • 'hacking is learning'
Re: CB450 Tracker
« Reply #6 on: Oct 19, 2017, 16:41:28 »
Cool build!
--
YZF750/1000R The Fly
KZ 750 Twin
ZRX 1100
The Shovelhead springer chopper
A bunch of KZ's...some Suzukis', and a disassembled CB550
--

Offline Pete12

  • Posts: 4
Re: CB450 Tracker
« Reply #7 on: Today at 01:02:12 »
Thanks Guys...

Got the triples profiled finally. I ended up with 55mm of offset which equates to around 95mm of trail when it's all assembled, which should be pretty good I think.

This is the lower one and the two holes in the bottom are for the steering stops which will just be a couple of cap screws that will locate against the existing frame lug.

https://i.imgur.com/1SpICl8.jpg[/img]]

This is the upper one and the two holes in it are for the handlebar clamps. I am going to use Maico rubbers on the clamps to try and reduce the vibration that these CB450's are rumoured to have...

https://i.imgur.com/mcTxuTS.jpg[/img]]

The forks assembled to check the fit. The steering stem will get pressed in and then I can install them and get on with making the handlebar clamps.

https://i.imgur.com/sQpLJCP.jpg[/img]]

I bought an Acewell tacho from Dime City Cycles (what a great bunch of guys to deal with there) so I'll make up a mounting bracket for it once the handlebar clamps are finished - it will attach to the front of the top tree

https://i.imgur.com/GY5CVAu.jpg[/img]]

Apologies again for the varying size and quality of the photos - not too sure what's going on there but I'll try and get some uniformity with them (I hope)...