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Post by thetank on Jul 21, 2008 14:54:55 GMT -5
I am not happy with the stock subframe. I want to cut the old one off. I want to shift the entire sub 1.5 inches up. I need the inches for three reasons: 1) The rearset design I am developing will leave my legs too folded to function properly. 2) The extra ground clearance in turns, as well as the rear wheel clearance for the rear fender, and 3) Will give me the room to fabricate a proper upturned exhaust for racing. Has anyone else attempted such a thing? Thanks in advance. Frank
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pcnsd
Full Member
Posts: 113
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Post by pcnsd on Jul 21, 2008 20:52:12 GMT -5
I have cut up a fair number of frames in my time, but have never completely separated a frame component, reattached it and been happy with the results. When you separate the sub-frame it will move in unpredictable ways without bracing. You will need to construct a fixture ($$) to get it back together straight. There is a sub-frame mod called the "Lefever mod" after its inventor, usually found on mid seventies Husqvarnas. You cut loose the top two tubes only. Heat the rear tubes first just below the shock gussets and bend the top of the sub-frame back and up. Then heat the rear tubes again as low on the tubes as practical and move the sub-frame back to position on the upper frame tubes and weld. The mod will raise the seat position and move the top shock mount forward allowing more travel to the rear wheel. Careful work will provide good results, shoddy work will send the frame to the trash heap. The maximum change doing the Lefever mod is .75 -1.0 inches. This link shows John doing the mod but not all the steps. www.vintagehusky.com/framemods.htmGood luck PC |
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Post by thetank on Jul 23, 2008 8:10:35 GMT -5
Thanks, PC. I appreciate the input. After your input, I have thought long and hard about this mod. I believe that I can do what I need to do by simply cutting off the "unnecessary" portion of the subframe (aft of the shock mounts), and weld up a simple U-shaped piece of tube steel in place of it. I will keep you posted with pics. Frank
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Micky V
Junior Member
1978 SR500
Posts: 43
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Post by Micky V on Jul 23, 2008 23:05:20 GMT -5
I was thinking of doing the same thing Frank. That chunky rear end has to go! I'd like the U shaped rear to sit nicely under the custom seat I'm about to start on.
Please let us know how you go.
Mick V
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pcnsd
Full Member
Posts: 113
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Post by pcnsd on Jul 24, 2008 22:42:39 GMT -5
I believe that I can do what I need to do by simply cutting off the "unnecessary" portion of the subframe (aft of the shock mounts), and weld up a simple U-shaped piece of tube steel in place of it. Weld on frame loops in various configurations are available from most dirt track frame shops. Cost is about $150.00. Cut off the old, slide the new frame loop into the old tube openings at some proper position for the tail section being used and weld together. This may help, Look under Chassis/Frame: www.flattrack.com/Suppliers%20List.htm |
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Post by thetank on Jul 26, 2008 22:57:50 GMT -5
Thanks for the head's up, pcnsd! I will research that immediately after this post.
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