My CB450 Project

kachunk

kachunk

Active Member
Hi guys - just wanted to share my build. I started it in 2009 and its been a long process...
It was a running bike when I bought it. I knew I wanted a bike that would perform and look like it was built for speed. I actually did most of the work in 2010 and 2011, but I'm just now getting to posting the pictures ad details.
As purchased:





Beginning disassembly:


Noticed the lower triple was repaired, it coincides with a big dent in the tank and the gouge in the stator cover...
 
Stripped the bike down, and removed the rear passenger peg brackets, battery box



Stripped the gray paint from the engine and planned to freshen it up.





Valve seats looked a little beat up.


Bores looked ok so I just planned to hone them and replace the piston rings.


 
Some "after" pics. I reused the pistons. There was some pitting, but I thought it would be ok.





Had the head powder coated high temp black but left the cam area brushed/natural. Turned out pretty good. I instructed the powder coater about what I was looking for and they did a great job with it.


 
I really wanted a brushed finish on the engine. I did not want mirror polish or black paint. I spent hours scrubbing with scotch brite and steel wool to get the finish I wanted. Then I tried several different clear coat paints to see if they would stick. I believe I had the best result with semi-gloss duplicolor clear.





Reassemble now:



 
I then began working to find the right tank. I thought I wanted a CX500 Deluxe tank, but after mocking it up, I just couldn't get it to do what I wanted. Its an inch or 2 longer than the CB450 tank, and I couldn't get it to sit the way I wanted. Its also really wide. I also tried a CB200 tank, but ultimately I settled on a CB500T tank. I wanted it to sit as low as possible so the bottom edge of the tank would be parallel to the frame under the seat area. So I ground off the front mount and lowered it a little. I was also going to have to fab up a rear mount.









Removed some bracketry from the rear of the CB500T tank so it would sit lower to the frame.
 
Ok rear hoop time. I am an absolute novice welder so please pardon the boogers.... Awful penetration, I know they suck





Here is the mock up of the seat and tank:

 
My idea for this bike was to apply some modern tech (carbon seat) to make a mix of old and new. I purchased a used front end assembly from a 2007 GSXR750 and worked to adapt it to the CB450 frame. The GSXR front end has black adjustable upside down forks, which I knew would look great and offer good performance. I took measurements from the CB450 steering stem and triples and I had a machine shop make a custom steam that would adapt the GSXR triples to the CB450 neck. Measure twice, cut once!




Mockup with the jack under the frame. Not enough room between the rear frame and the tire:




Tried some rear shocks from Works, but they were not long enough for my setup. I knew I was going to change to 17" wheels, and I thought that might also improve the clearance. I spent alot of time trying to figure out how to resolve this...

 
I wound up using shocks from a 90's Kawasaki ZRX1100. They are adjustable and about an inch longer than the OEM shock, which is longer than the Works pieces I had. But the lower mount is an eye, and the stock CB450 is a fork.


I also sourced a CB750 swingarm for several reasons. Its stiffer. It's a little longer, which brought the top point of the tire further back and away from the rear frame hoop. This also helped the bike look more proportional. CB450's rear tire is tucked in close to the engine, and it can look stubby.
The 750 swingarm also has a wider opening near the swingarm pivot, which allows for a wider tire. I had to modify it to fit my frame. I added bosses to mount the ZRX shocks and I had to narrow it near the swingarm pivot to fit. I installed bronze bushings and mocked it up. The pic above does not show the 750 swingarm. I can't find any pics of it until the bike is assembled. You will be able to see it in the next few posts...

So next was the battery box. I knew I wanted to run a modern headlight, so I wasn't confident with a small battery. I know the charging systems on CB450's are not robust. A full size battery wouldn't fit under the seat hump, so I thought mass-centralization would be a good option. I decided to mount the battery under the swingarm pivot. Low and in the middle of the bike. This was my first attempt at sheet metal work. Its not pretty but it works.




I went overkill with the mount. Its offset to 1 side to allow clearance for the drive chain.

 
Welded on new rear set mounts. Removed old rear fender mount (looked like a brace on rear frame). I chose aftermarket rear sets from a CBR600RR, because they had short mounts that wouldn't position my feet too far rearward.



Headlight mounts. I used a stock CB450 bucket, but modified it to fit the headlight that I wanted. The headlight I wanted had a very short bucket that didn't look right at all. I grafted the 2 buckets together and used epoxy to bond them together. It worked great. The headlight is actually a Hella Black Magic driving light.




 
Wheels and tires. I contacted Rad Mfg and they made me a front hub to fit the GSXR rotor and axle. The rear hub is from a CRF450 to fit the rear rotor I chose. It has a cush drive so it will be durable on the street.






The engine shown in these pics is a stuck motor from a junkyard. Its just for fitment.
 
I encountered issues with the front brake caliper interfering with the wheel spokes. The Rad Mfg hubs are wide, they are intended for supermoto applications. I attacked it 2 ways. I made spacers to move the caliper out radially, so its now further away from the axle. I spaced it as much as I could while ensuring full surface area of the pads contact the rotor. There was still interference. So next I ground down the backside of the caliper to allow clearance. This was not ideal, but I bought a scrap caliper and removed material until I broke through to the piston cavity. Then I took my good caliper and removed enough to clear the spokes while leaving enough material to make me feel comfortable.



 
Ok I remember why I made the change to the CB750 swingarm. The rear hub was too wide and there was no room for the sprocket between the hub and swingarm/shock. The CB750 swingarm is much wider at the rear axle and allowed clearance for the sprocket. With the tire I was running, I also needed an offset countershaft sprocket. I had one made (professional welder this time) with a 1" spacing.



Now that's a real weld!
 
I am missing some pics but here we are. Frame and CB750 swingarm were powdercoated. Its kind of a pewter color with metallic in it. Motor in.
You can also see the 2 little tabs I added for the rear brake master cylinder. I had also cut down the rearset mounts, the CBR pieces only needed 1 bolt hole.



Getting Dyna ignition wired, Acewell gauge, clutch.
 
Here is a pic with the CB750 swingarm. You can see there is a lot more clearance to the rear frame, allowing full suspension travel. I realize I made a mistake by selecting the CRF rear hub. I had a hard time finding a rear sprocket that wouldn't completely screw up the ratios.




Mocking up exhaust. I bought a set of CL pipes with rusty mufflers and cut them off. I got a muffler and adapters from 7th Phase Inc. Welded them up and painted with several coats of VHT. Had to angle it out around the rear shock. Black pipe wrap to finish the pipes. I know its cliche, but it works for me. Painted the wrap with VHT.

 
Tank painted. Had a local custom shop do it. Nice metallic brown with red striping. I love it. It sits nice and low and flows with the bike. But I ran into an issue with the spigot and the carbs. I had to make a special fitting that was short so the fuel hose could clear without kinking. I wound up with an inline fuel valve and individual filters for each carb.



Got wiring routed and sorted (generally). I want to redo it at somepoint. I think there is a better way to route some things, but at least its functional.









I spent some time jetting the carbs, but it still isn't quite right. Once it gets hot it does all kinds of weird things. Need more time to develop. Its ridable, but definitely not 100% sorted.
There are a ton more details about this bike I didn't describe here. Some other items of interest: kick only, rick's stator and rectifier, GL1000 ignition, VM30 carbs, modified GSXR kickstand, Custom Dynamics tail light, frame hoop and seat are from Gage Werke Composites, aluminum motor mounts, CRF450 rear brake rotor and caliper. Tank painted by Detroit Brothers Custom Cycles, Countershaft sprocket from DG Chassis, the rear tank mount, the clutch actuator. I had a lot of help and advice from people and it really made a difference when I got stuck. Hope you guys enjoy it!
 
Nice build, I personally would've replaced the pistons, any mark/scratch/indent is a place for detonation to start.
 
I've had an internal battle for a while about removing that rear fender mount on the back of my frame like you did. Have you noticed any problems with the bike after cutting it off?

Sorry to revive this post, but like I said, I've been having a mental battle with myself over this. I want to remove it but most people here on the forum seemed to think it was definitely structural. How do you feel about it having removed it?
 
I haven't experienced any problems since removing that piece. I did ask Team Hansen about it, they said no problems with removing it. (this isn't a race bike). I think its ok as long as the rear of the frame is tied together with a hoop.
 
Thanks for the reply, pretty sure mine is coming off as well. Awesome build by the way, always nice to see someone else going through a build on the same bike as me, provides extra knowledge and inspiration.
 
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