Jared's 1982 CM450C Cafe Project

1969Honda said:

In regards to your fork/axle swap comments don't worry so much out the stem and axle diameters. Measure out the bearing dimensions and then model up your own axle and stem. I don't think it would take much for you to figure out a bearing size that is easily available on your rims and then machine a corresponding axle to fit the forks and wheel. As for the stem, it's a actually pretty common to swap stems on the lower triple to get right combination of length and bearing size. You might be limited on your budget to the VFR wheels, but bearing conversions aren't to expensive and turning a new stem or axle shouldn't be to bad either. Also check out misumi-usa.com before you commit to a machinist on the axles, they have pretty competitive pricing for custom shafts with configurable machining options.

On your VFR rear rim, don't be surprised if you have to make any spacers to push the wheel to the right to clear the swingarm as well. IIRC correctly they are so much wider/offset differently than the NT650 you will need to add an 8mm spacer or so, surf around the build threads on customfighters.com, they've got tons of builds doing the SSSA conversions on sportbikes that you can pull applicable information from.

Keep up the good work and post lots of pics for those of us who enjoy the unusual/unconventional!

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Thanks for the feedback CXMAN, much appreciated. I eventually solved the front forks / front axle issue by just going with forks from a 2006 CBR600RR and then using the exact front wheel that goes with that bike. You can't really see the fron wheel anyways since there are two brake rotors, and it doesn't look all that dissimilar from the '94-'97 VFR750 5-spoke wheel that I have. I picked up the sterring stem bearing conversion from AllBallsRacing, so I'm all set! Just need to fine tune the fork placement, triple trees, and spring rates. I also picked up all new seals for the forks just in case.

I did quite a bit of research into the VFR wheel before purchase, and actually found that the rear spindle is exactly the same part between the Hawk and VFR. Since I wasn't constrained to the Hawk spindle (just the hawk SSA), I bought the VFR750 rear spindle with the VFR750 rear wheel. I fit it up recently, and the wheel definitely clears, but I'll have to wait to get the tire on before I'll know if I need spacers. Very good input, and something I'll be paying attention to now.

Stay tuned for more pictures, I'm always working on something!

I like the single side swing arm. I'm interested to see how it looks.

HEY! I have a little progress to report on.... Yay!

So I got all the numbers I needed from the Honda Hawk forum for the Hawk's stock suspension geometry. Then I took some of my own measurements, crunched a bunch of numbers, and came up with this draft for my suspension geometry (see picture below). The main change here is that on the Hawk, the shock top mount is 25mm in front of the SSA pivot. For my bike, the shock top mount is 50mm behind the SSA pivot, for a total change of 75mm. The reason for the 50mm is because the shock's top mount is planned to be mounted on the outside, or rear of, the frame's vertical member.

In an effort to minimize this change as much as possible, I found the shortest shock (eye-to-eye length). This is the CB900f (aka Honda 919). It is 27mm shorter than the Hawk shock, and about the same spring stiffness (100lb/in less stiff, since my bike will be lighter). Still though, with the shorter shock, I still have a significantly different suspension geometry. When I mocked up the bike with the frame and swing arm (see picture), it did not look as drastic as the calculations would suggest. I will definitely have to verify all the calcs with the real world!!

I'm going to take this to my structural steel engineer friend and run some force calculations to further the desing of the shock top mount. Right now, I am assuming rider (170lbs) + sprung mass (400lbs) + driving dynamics + shock loading = 2,000lb of force. Some of that will be taken by the shock/damper, so I'm going to do some more research to find out how much will actually be transferred to the frame.

Thanks for looking and let me know what you think!

Wow I was working on a project like this about 3 years ago the guy did not like how it was going and got a cb350 instead ;D Its still here some place if you want I will take some pictures for you.

cobraace2 said:

Wow I was working on a project like this about 3 years ago the guy did not like how it was going and got a cb350 instead ;D Its still here some place if you want I will take some pictures for you.

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That would be great. I'm interested to see how everything was fit together. How far along is the project?

it was a runner he beat on for a month and then said it still looked ugly ;D and wanted to change the frame again I told him what he owed me and that was that :

Here are some pictures the swinger is sting 1/2 " to the right and the sprocket goes on the back side of carrier no offset sprocket

Thanks for the pictures CobraAce, looks sweet.

I can't tell very well from the third picture how the swinger was incorporated into the frame... Do you know anything about that? Regardless of the swing-arm pivot shaft diameters (Hawk is 15mm and CM450 is 14mm), the pivot of the swing arm was in a spacial conflict with the engine/transmission case...

It's been a while since I've dropped by this place, but glad I did. Shit you guys do is fucking cool and always such an inspiration. How's this going anyway?


Ended up here, looking into fork replacement for my 82 cm450c, btw.

jaredc used 650 swinger bolt hog out frame and cut and shim must be at least 1/2 inch to the right side move sprocket to inside and check for alignment yes it clears trans . after mounted lift bike let swinger fall till ride hight looks good weld top mount 8) or you could get all technical and and get a cheap 13$ starrett angle meter set your head angle like you wanted.

rattpunk said:

It's been a while since I've dropped by this place, but glad I did. Shit you guys do is fucking cool and always such an inspiration. How's this going anyway?


Ended up here, looking into fork replacement for my 82 cm450c, btw.

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Don’t how hes doing but mine is a bout to be an organ donor ;D unless you want to buy it 8)

Yeah, think mine will be going to scrap. Hit the back of a van in SF. Front forks, headlamp, clipons, and other little bits are trashed, but rear frame damage is the nail in the coffin. Coule cut and weld, but have nowhere to work on it and no welding equipment...


The one day I decide to ease up on the lane-splitting too... fuck city traffic.


Was thinking of full rebuild, but honestly the bike was fun and learned a lot working on it think it's time to move on to the next.


So, looks like there are two CM450Cs donors out there for anyone reading this.


I'll be putting up a post with pics and info this Saturday. Then a Criagslist add sometime next week.


oh, and sorry to derail the thread Looking forward to updates!!

Finally back to working on the bike after new work responsibilities and a couple months of being distracted with other projects around the house. Here's the rear monoshock conversion top mounts!

I just used cardboard and scissors to get the right profile to match the frame. Then I made a bracket out of wood with the cardboard templates, a jigsaw, and a sander. Then made the two steel brackets with a port-a-band and a grinder. All-in-all, not nearly as difficult as re-designing the suspension geometry. It took a lot of calculations, but this final setup should be the one. I'll tack-weld the mounts on, put the motor and everything on the bike, see where it sits, and adjust from there if necessary.

rattpunk said:

It's been a while since I've dropped by this place, but glad I did. Shit you guys do is fucking cool and always such an inspiration. How's this going anyway?


Ended up here, looking into fork replacement for my 82 cm450c, btw.

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Thanks Rattpunk. I probably got way in over my head for my first Cafe Build. But, when someones says "...definitely do NOT use a single swing arm, especially with an early 1980's 450cc bike", I can't help myself!!!

I'm just about to weld on the top mount for the rear monoshock conversion. Should look pretty sweet. The only other issue I've had is that the swing arm pushed the rear sprocket out about 5/8" from the front sprocket. But I found a shop in Oregon that made me a custom offset front sprocket. Hoping to get a bike that actually rolls around here in a couple weeks!

Here's some new pictures for some work I've done over the past few months. Really feel like I'm making some headway now.

PS - The guy welding is a millwright/motorcycle enthusiast that I work with... I'm 32 and most of my hairs are brown, and he's been welding longer than I've been alive!

Here's a dry-assembly I did a couple months ago.

I have been working on the rear brakes right now, which is proving to be another very difficult hill to climb. I elected to use the VFR750 5-spoke rear wheel. And since the rear axle/spindles are nearly interchangeable it's been an easy swap. That is, until I tried to mesh the VRF750 rear disc brake with the Hawk NT650 rear caliper. Not so easy! I'm getting a new caliper bracket CNC'd next week though. should be exciting.

Hawk to VFR wheel conversion - http://www.hawkland.de/beatty/VFR_Whl.html

you still need some very substantial outboard support on the swinger pivot and strengthening of the frame between the swinger pivot and top shock mount

xb33bsa said:

you still need some very substantial outboard support on the swinger pivot and strengthening of the frame between the swinger pivot and top shock mount

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You're absolutely right. I'll be taking care of that with the brackets for my rear set pegs. I already have the plates made, but figuring out the right-hand side with the brake pedal will be tricky. Definitely planning to put stiffeners on the outside of the swing arm though. Great catch

the frame has been welded and ground down on both side in 2 spots each side

near where you put the swingarm if those welds crystallized and or were ground down to much

then the frame is essentially been cut in half

i would consider jack plating the sides of the frame if not making a wrap around stiffener

So since last December, I got engaged, married, moved into a new house, and just now picking the porject back up!!! It has been a long 8 months with no motorcycle work in my life, but a super-smart and talented buddy of mine helped me get some momentum again. Here are some pictures from the last 2 weekends!
1.) Remove move "structural" parts deemed "non-essntial". Lighter and faster now! (
2.) Mock up bike so we know what the hell we're working on.
3.) Mock up foot control backets with cardboard, then plywood, and get right foot positioning.
4.) 3/4" tubing (1/16" wall thickness) for stiffeners for the outside of the swingarm to the chassis
5.) Plasma cut some new brackets and machine the swing arm bolt to fit!!