Honda CB450 Cafe Racer

Mike450

New Member
New project time! This was the bike that started my vintage Honda obsession and after nearly ten years of getting pushed aside it’s finally time to finish this Honda CB450 cafe racer project. I bought this non-running, mostly complete 1972 Honda CB450 K5 back in 2010 to give myself something to tinker on and get better acquainted with motorcycles in general. At the time I had a 2008 Suzuki SV650 and a 2008 Triumph Bonneville T100. Neither of which needed me taking them apart to see how they worked.

The tank and side covers had been painted several times, it was missing it’s original seat, and although it was a low mile bike, it had endured a hard life. I later discovered that the frame was bent which further attests to the abuse it had suffered at the hands of its previous owners. I was able to track down a titled, straight frame from a 1973 K6 on eBay to replace the bent one so technically this is now a 1973 CB450 even though the majority of the parts are from the original K5.

As many of us do with our first project bikes I immediately started ordering a slew of parts and chopping tabs and brackets off of the frame (the bent one) without having a solid plan. Ultimately I settled on a cafe racer style bike as my target. At the time I was watching Cafe Racer on Velocity and reading Cafe Racer magazine so I suppose it was inevitable. The following year I bought my 1974 CB360G and quickly lost interest in the CB450 project. After all, the CB360G was a complete, running bike that I could jump on and tear around the back roads with. So, the CB450 sat for several years while my collection grew and pushed the CB450 further and further back in the garage.

A few years after that I decided that I lacked the motivation to finish the bike and passed it along to my brother. We tinkered with it a bit but then it continued to sit and collect dust in his garage. Which brings us to the present. With the CB77 restoration complete, I needed a project. Ideally one that wouldn’t cost me a pile of money. So the CB450 cafe racer is back in my garage and with a little luck, and a little of my brother’s money, the kids and I are determined to complete this project and get it back on the road by next spring.


Getting ready for the 5 hour drive home.



First look after unloading it. I stuck latex gloves between the filters and carbs to keep the rain out on the drive home.



To my amazement the bike fired right up. I always drain the carb bowls when putting bikes away for any length of time and this one was no exception. We had also fogged the cylinders.



We've settled on a seat from Tuffside. Here is a quick Photoshop mockup. I have no idea what color the tank will be. We're miles away from that step.

 

Mike450

New Member
Already has a proper look to it.
I think we're pretty close to the overall proportions. Originally I had bought a BCR fiberglass tank/seat set which pushed the seating position way back. Now that we've decided to run the stock tank and shorter seat it changes things a bit. The foot rests need to come forward for sure but I won't know how much until the seat arrives.

looks pretty good to me.
Thanks! Coming off of a long restoration project I'm excited to have a bit of freedom with this project.
 

Mike450

New Member
I installed the Red Wing shocks I was running on my other 450 for a while to try and get an idea of the shock length to look for. These are 13" center to center compared to the stock 12 3/8". With a properly adjusted chain the max is around 13 1/2" which still leaves a little clearance between the chain and top side of the swing arm. Unfortunately the Red Wings are too fat at the bottom to run the chain guard so I'll have to find an alternative or try modifying the guard slightly to clear the shock.

 

Mike450

New Member
Here's a quick project update. The Tuffside seat I ordered arrived last week. I'm very impressed with the quality and workmanship. I had heard good things about the seats in the past but had never seen one in person. The rear hoop that was on the frame already was setup for a BCR tank and seat combo which is about 4.5 inches longer than the setup we're working with now so the hoop needs to be shortened and angled up about 12 degrees to follow the line of the new Tuffside seat. I took advantage of the cool, dry evening we had here in SW PA yesterday and got started on the modifications. Weather permitting, I'll tack the modified hoop in place this evening and move on to the the mounts.













 

Mike450

New Member
Progress has been slower than I'd like but that's the way it goes sometimes. I ran into a bit of trouble trying to modify the frame hoop to follow the "egg" shape of the Tuffside seat's tail end. My first attempt failed as you can see in the video below but fortunately I had the hoop on the original bent frame to give it another try with. The second time around worked out much better.






 

Mike450

New Member
Hey folks, Just a quick update, mostly pics, on the CB450 project. I've got the seat mount and hinge setup basically complete. One of my favorite things about these older Hondas is the flip up seat to access the battery, etc. so I figured why not make a similar setup for this project as well. The weight of the rider will supported by several rubber pads and the whole thing will be held in place by 2 quick release latches.



Mocking up the electronics tray out of wood.



The actual tray is made out of 16 gauge steel sheet. It took me 2 attempts to get the dimensions just right but it was a pretty straight forward process. I cut it out with an angle grinder and then made the bends with a vice break.



Checking for fitment. The battery can fit in either the tray or under the seat hump. I'm leaning towards the seat hump just to keep things from getting too cramped.



Lots of masking tape and paint stir sticks used in this project.

 

Jimbonaut

Over 1,000 Posts
DTT SUPPORTER
Nice, I like the flip up seat plan. What quick release latches will you be using?


Sent from my iPhone using DO THE TON
 

Mike450

New Member
Quick update on the CB450 project. I got the hinged seat mount and latching setup worked out and installed. I also built the electronics tray and mounted that. Next up is the battery mount and then on to the rearsets.










 

Mike450

New Member
Ah man that's a super cool idea for mounting the seat!
Thanks. It does use up a little space in the electronics tray but with the battery under the seat hump I don't think it will be and issue. The trickiest part was getting the hinge mounted where it would allow enough clearance between the seat and frame as it lifts up. I had to adjust and relocate the hinge 3 times. Worked out in the end though.
 

Mike450

New Member
Small but important steps this week. I worked out the location of the rearset mounting points. The tabs were welded to the frame and then I mocked the mounting plates up with some wood scrap (which quickly broke) and then in 1/4" PVC. Once I get all the linkage squared away I'll make the final plates in 1/4" steel.






 

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