One more 180 tire conversion FZR1000 swinger

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Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

One more 180 tire conversion FZR1000 swinger

#1 Post by Ollies930 » Wed Sep 03, 2014 2:40 am

RZ350 Frame cut b 1.jpg
RZ350 Frame cut b 1.jpg (241.79 KiB) Viewed 3879 times
Trying to build a chassis for vintage racing, allowing 17x5.5 wheels with 180 tire in this particular class.
Wanted to do this the simplest way possible in the least visually obvious way. After doing the math to
see how much room I needed, I decided to widen the frame by approx. 18mm, which should give me
the required room for 180 tire using an 18.6mm offset sprocket sourced from fastfromthepast.com.
Then I cut the frame and used the existing swing arm pivot with spacers totaling about 19.5mm in
spacers (expected some flex back) and welded in some clam shell pieces I made up to fit the four
spaces where the frame was cut. Based on the recommendation of my welder, who repairs light aircraft
frames, I made the ends of the clam shell pieces diamond shaped, to lessen the chance of the frame
cracking along the welds. Grind off some of the original paint and off to the welder it went.
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RZ350 Frame cut a 1.jpg
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RZ350 Frame cut 1.jpg
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Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

Re: One more 180 tire conversion FZR1000 swinger

#2 Post by Ollies930 » Wed Sep 03, 2014 2:42 am

Clean up welds with solvent/brake cleaner and hit it with some epoxy paint.
Attachments
RZ350 Frame welded b 1.jpg
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RZ350 Frame welded 1.jpg
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Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

Re: One more 180 tire conversion FZR1000 swinger

#3 Post by Ollies930 » Wed Sep 03, 2014 2:48 am

Frame did flex back somewhat, but not enough to make install of swing arm impossible.
Swing arm was shortened at the pivot point by approximately 10mm/side and new IKO
bearings installed (25mmx33mmx20mm). Original bearings were 30mm wide, so the
20mm wide bearings were perfect for the 10mm reduction in width.
Will post pictures of R6 wheel and machined sprocket carrier later to show what else
was needed to align everything.

mkane
Posts: 921
Joined: Wed Feb 20, 2013 11:43 pm
Location: Cloverdale, CA

Re: One more 180 tire conversion FZR1000 swinger

#4 Post by mkane » Wed Sep 03, 2014 10:17 am

This bike came to me with 17" and a 180 tire. Don't believe the frame was cut. Seems like a lot of work. I'll sit back and enjoy your build.
Image

Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

Re: One more 180 tire conversion FZR1000 swinger

#5 Post by Ollies930 » Fri Sep 05, 2014 10:22 pm

Interesting, I found that for the chain to clear the tire by 2mm on one side and the frame by about 3mm on the other side, I ended up having to widen the frame by 19.5mm between the swing arm pivot points. At that point everything was string lined and the wheel was centered in the frame and aligned with the front wheel. Then the front sprocket, which was an 18.6mm offset needed to be spaced out a further 1.5mm and the rear sprocket carrier and spacers machined to push the rear sprocket more towards the center.
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Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

Re: One more 180 tire conversion FZR1000 swinger

#6 Post by Ollies930 » Fri Sep 05, 2014 10:26 pm

After that the swing arm needed a 3/8" thick pad welded on for the rear brake arm to rest on and drilled and tapped for a securing bolt.
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Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

Re: One more 180 tire conversion FZR1000 swinger

#7 Post by Ollies930 » Fri Sep 05, 2014 10:28 pm

Then a little bit of trimming on the front sprocket cover to clear the offset sprocket.
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20140905_160030.jpg
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Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

Re: One more 180 tire conversion FZR1000 swinger

#8 Post by Ollies930 » Fri Sep 05, 2014 10:32 pm

And the finished product (just needs some minor touches and a good cleaning). And the front wheel needs to be powder coated black.
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Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

Re: One more 180 tire conversion FZR1000 swinger

#9 Post by Ollies930 » Sat Sep 06, 2014 12:05 am

Incidentally, I retained the original linkage from the frame to the shock and used a couple of pieces of 1"x3/8" aluminum plate from the shock to the swing arm linkage, 104mm center to center 12mm on one side and 14mm on the other side (those dimensions worked for my long Fox shock to raise seat height to 32"). Round the ends with a 4" disc sander and it is done. Interestingly, with the FZ600 swing arm and linkage, the suspension was very soft, but with the FZR1000 swing arm I had to back off the preload to get the right amount of sag and it feels a lot stiffer.

Ollies930
Posts: 109
Joined: Fri Jun 29, 2012 11:17 am

Re: One more 180 tire conversion FZR1000 swinger

#10 Post by Ollies930 » Sun Sep 07, 2014 5:30 pm

Swing arm linkage, could be made prettier, but it works.
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