Project Bimota CB400F
The basic frame layout is close to being finalized, and I am spending a lot of time right now getting the rear swingarm and suspension sorted. I have been using Tony Foale's Suspension Kinematics software, http://www.tonyfoale.com to analyze the rear suspension system. As a baseline I have the performance curves from a 2005 CBR600RR, and a VF500 Interceptor, and I have been modeling my new parts to mimic the suspension action of the CBR. But, there are many ways to physically build the parts and have them generate similar curves.
![](./user/gimage/vf500-susp-info_500_340.jpg)
Snap shot of the parameters used to calculate the wheel forces vs wheel movement, VF500.
|
![](./user/gimage/cbr600rr-susp-info_500_340.jpg)
Snap shot of the parameters used to calculate the wheel forces vs wheel movement, CBR600RR |
This is the suspension rising rate curve generated by Tony Foale's suspension kinematics software for a VF500 Interceptor. What we are most interested in is the wheel force rate vs wheel movement. The curve steepens at the end of the suspension stroke, presumably to provide a smooth ride for a single person, and still deal with the load of a passenger without bottoming. |
This is the suspension rising rate curve for a CBR600RR. Note the more linear curve of the wheel force vs wheel movement. I think this reflects the fact that the bike's sporting intent. The designers were less concerned with rider comfort, or accommodating a passenger than when designing the VF500. |
I have analyzed the design of swing-arms from a CBR600RR, a CBR600F1, and a VF500 to get an idea of how stiff Honda is making their swing-arms. It is interesting to see the progression in stiffness from 1983 (VF500) to 1990 (CBR600F1) to 2005 (CBR600RR) . I applied the same 400 lbs per side torsional load on the arms.
April 16/2010 - I have added in a new gull wing swingarm that I designed fabricated out of 1.5" OD x .0625" wall and 1" OD x .0625" round tubing. Because this bike is more street/custom oriented vs. a race/track bike I will probably go with the gull wing design, even though I could have made it simpler and lighter, I like the look of it, and it is reasonably strong and light.
![](./user/gimage/b1328_350_325.jpg)
- CBR600RR swingarm assembly, strong but heavy - 17 lbs
|
![](./user/gimage/b1327-para2test3displacement_350_325.jpg)
- 400lb load on each side of arm, 0.003" deflection
|
![](./user/gimage/cbr600f1swingarm_350_325.jpg)
- CBR600F1 Swing-arm, welded steel - 11 lbs
|
- 400lb load on each side of arm, 0.060" deflection
|
![](./user/gimage/vf500-swing-arm_300_278.jpg)
- VF500 Swing-arm, Cast Aluminum - 6.5 lbs
|
- 400lb load on each side of arm, 0.137" deflection
|
![](./user/gimage/b1374_300_218.jpg)
- Steel tube swingarm, 11 lbs.
|
![](./user/gimage/b1374fea-disp_300_240.jpg)
|
![](./user/gimage/g1205_300_277.jpg)
|
![](./user/gimage/g1205fea_300_277.jpg)
|
While researching CBR shock specs, I came accross a site that had a really nice write up on rebuilding a CBR600RR Showa shock. I received permission from the site owner to reproduce the write up on my site, because I didn't want to risk losing the information. Click CBR600RR Shock Rebuild to see the reproduced article, or http://www.peterverdonedesigns.com/600RRshock.htm to see the original article. Thanks to Peter Verdone for a great write-up.
I am slowly getting around to actually building parts for this bike. Detail Pics |