Chewtoy Posted June 1, 2013 Share Posted June 1, 2013 After accumulating parts for a few years, I finally started the upgrade to my CB750F swingarm. The original arm is made of reinforced tubular steel, and flexes very noticeably when hitting bumps in turns. A popular upgrade in Japan is installing a CB400SF swingarm. So, I got a CB400SF arm via Rinkya, and a chain guard and rear brake system to boot. Finally got a set of Kawasaki ZXR shocks to mount up, and a set of F2 rims, which I got refinished @ FastForward wheels here in LA - a great wheel shop. Then I got the swingarm pivot set up to use the stock shaft in the Honda frame, and the rear wheel set to use the CB400SF axle. First mount shows the wheel is ~ 3/8" off to the right. I'll get some better measuring tools and get some numbers I can get bushings cut from. Might have to cut down the sprocket carrier as well (sigh). Oh, and the top bushings on the shocks don't fit the pins on the Honda frame. Need some work there as well. Perhaps some delrin or teflon bushings will do the trick. If anyone has some helpful thoughts, please LMK. Pics here: https://plus.google.com/u/0/photos/10798003...644367370603601 Quote Link to comment Share on other sites More sharing options...
XXitanium Posted June 2, 2013 Share Posted June 2, 2013 Nice. Are you trying to do it so it can be easily turned back to stock? Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted June 2, 2013 Author Share Posted June 2, 2013 Nice. Are you trying to do it so it can be easily turned back to stock? Well, it could be turned back, no frame mods, but it's pretty crappy with the tubular swingarm. Just going for a tasteful mod. Putting Honda F2 forks on the front next, and I have a CB900F motor waiting on the shelf as well. Going for a similar look as this guy's bike. Have the blue bodywork here as well Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted June 9, 2013 Author Share Posted June 9, 2013 OK, I grabbed some copper pipe from the hot water heater replacement last month, and made up some temp spacers for the swingarm pivot. I just spaced the drive side a washer's thickness from the left hand frame side, and took up the rest on the right side with a temp shim of copper pipe. Lined up the sprockets with the mark 1 eyeball and made a temp shim, Will go to get a el-cheapo laser and make fine adjustments. The brake side of the axle isn't shimmed yet, but I can see I'll need to extend the tab for the brake backing plate. Ordering new seals for the rear wheel, and also found new driveline buffers on ebay for cheap, so things are looking good. Once the seals show up, I'll do the final measurements, and get the shims made up. One thing, the guy that sold me the shocks sold me two right hand shocks. Wonder where I can find a 'KYB' decal for the left hand shock Updated the album with the weekend's work. https://plus.google.com/photos/107980032549...644367370603601 Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted June 15, 2013 Author Share Posted June 15, 2013 Well, still waiting for parts, but in the meantime, found a nice CAD program at www.sketchup.com to draw the spacers. The dimensions in the below are ALL WRONG, this was just a test. Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted June 24, 2013 Author Share Posted June 24, 2013 Got the laser set, and made some adjustments. Looks aligned. Got the F2 rear wheel seals, check bushing sizes, and finalized the blueprints for the machinist. The rear brake tab has about 50% engagement, and the disk could stand to be about 1/2" larger. Anyone know what other disks fit the F2 rear hub? More photos at https://plus.google.com/photos/107980032549...644367370603601 Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted June 26, 2013 Author Share Posted June 26, 2013 Found custom brake disks here: http://www.bikehps.com/isr/isr_brake_discs.html Price is not too bad. looks like this will be one of the finishing touches for the project. Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted July 29, 2013 Author Share Posted July 29, 2013 Finally got my machinist working on the spacers. Also, Honda sells the top shock bushings from the original Honda shocks for only $3 and change each. So I hope to not need to machine up some bushings for that. Should pick up the bushings on 8/3. Amazingly, Honda still sells the upper shock bushings so I can pop them into the ZRX shocks to solve the problem of them having the wrong ID for the frame pins. Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted August 17, 2013 Author Share Posted August 17, 2013 Got the bushings back from the machinist, and did a test fitment. Axle/wheel end is good. One bushing on the swingarm pivot is too thick and is riding on the end of the swingarm instead of the inner bearing race. Am taking them back for a tweak next week. Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted September 14, 2013 Author Share Posted September 14, 2013 Got the bushings back after two three tries @ the critical chainside swingarm bushing. My great idea about using Honda top shock bushings failed, went with delrin inserts. Bolted it all up and it looks gooood. Now to get a tire and take her for a ride! I have a CB400SF chainguard too More photos at https://plus.google....644367370603601 Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted September 14, 2013 Author Share Posted September 14, 2013 . 1 Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted September 15, 2013 Share Posted September 15, 2013 Give us a ride report. Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted September 16, 2013 Author Share Posted September 16, 2013 Give us a ride report. It'll be a little bit yet, doing the forks now Might put in that CB900 mill sitting on the shelf as well... Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted February 2, 2014 Author Share Posted February 2, 2014 Finally got the tire on the wheel, and did a full test fitment. Now I need a longer chain (sigh). It all looks good anyway, though the arm does push the wheel back a couple of inches. Now to get a larger disk made, hook up a chain, and install the rear brakes. Have to admit, part of me wants to take the arm to a fab shop and pull the wheel forward a couple of inches. Perhaps before the final finish and assembly. For now, will complete the brakes and chain, and get the front end done. More photos in the album here: https://plus.google.com/photos/107980032549223313420/albums/5884644367370603601 1 Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted February 2, 2014 Share Posted February 2, 2014 Before hooking the shocks up, did you run the wheel through its travel to see if the tire would hit the fender? Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted February 3, 2014 Author Share Posted February 3, 2014 Before hooking the shocks up, did you run the wheel through its travel to see if the tire would hit the fender? No, good suggestion, will do that next weekend. Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted February 3, 2014 Author Share Posted February 3, 2014 Oh, can't shorten the swingarm, no clearance between the front of the tire and the swingarm. Am fairly confident that the wheel will clear the fender, this is a common mod on Japanese F-bikes. But will still check fender clearance. Quote Link to comment Share on other sites More sharing options...
RichardCranium Posted February 14, 2014 Share Posted February 14, 2014 Cool project. Sounds like its been a bit frustrating. That red/white/blue CB looks hot. Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted February 14, 2014 Author Share Posted February 14, 2014 Not really, just one problem after another to fix. The F bike is my first real motorcycle, so I have sentamental attachment. And I pulled the shocks and jacked up the tire, it clears the rear fender, but not with a lot of clearance for chain stretch. Other F-biked that have done this mod have gone to a different rear fender. I'll ponder my options, it's not a big deal. Might pull the old forks off this weekend. New ones are ready to be test fitted. Quote Link to comment Share on other sites More sharing options...
Cogburn Posted September 22, 2017 Share Posted September 22, 2017 It's been some time but I was wondering if you are still working on this project? I appreciate the detail you posted and wanted to know if you made any other progress with the CB750F? I have a 81' CB900F and just started working on the swing arm. I noticed you have the NC31 version which is longer. I just bought an NC39 which I hear is 52cm +/- 1cm from the pivot to the axle centerline. Maybe this can be an option for you? Also have a CB1000SF (Big1) swing arm but that puppy is long and wide. 1 Quote Link to comment Share on other sites More sharing options...
tomasmontagnini Posted December 2, 2022 Share Posted December 2, 2022 HEY I just picked up a cb900f and i want to do the swingarm, any tips? 1 Quote Link to comment Share on other sites More sharing options...
XXitanium Posted December 2, 2022 Share Posted December 2, 2022 A common upgrade was to find a CB1100F swingarm. I think there was a year of Suzuki GSXR that adapted fairly well also. Quote Link to comment Share on other sites More sharing options...
XXitanium Posted December 2, 2022 Share Posted December 2, 2022 On 6/1/2013 at 5:36 PM, Chewtoy said: A popular upgrade in Japan is installing a CB400SF swingarm. So, I got a CB400SF arm via Rinkya, .... Then I got the swingarm pivot set up to use the stock shaft in the Honda frame, and the rear wheel set to use the CB400SF axle. .... Pics here: https://plus.google.com/u/0/photos/10798003...644367370603601 Quote Link to comment Share on other sites More sharing options...
XXitanium Posted December 2, 2022 Share Posted December 2, 2022 Check out CB1100F.net also. How much work are you up for? CB900 Hornet swingarm and modern-ish wheels? Maybe some cutting and welding? eBay linky Quote Link to comment Share on other sites More sharing options...
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