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Lightening a narrow-case frame for racing

Posted: Thu Oct 01, 2015 9:29 am
by ElmrPhD
Hi guys,
Finally got my '66 350 "on circuit" - a true (long-coming) dream-come-true.
So, this is in the context of a race-dedicated narrow-case:
Was wondering if any engineering types have analyzed the prospect of removing all that metal that lies below and aft of the swingarm pivot point. It's obvious purpose is to support the passenger pegs (gone!) and center-stand (gone!), but does it also help resist the swingarm bearing bracket from moving? It is very tempting to cut it all off as it would save more weight than most of my other efforts, BUT I also recognize that MAYBE it still helps to stiffen the notoriously flimsy swingarm pivot. So, I really don't want to further weaken the weak point of a narrow-case frame.
It looks, from what I can see from posted photos, that the old factory racers (F3, see attached) omitted this metal, which supports my temptation, but I'd like to get an engineer's opinion.
Oh, and, no, my bike has not YET had the cool mod' of bracing extended/widecase swingarm bushes to the rear (sub-)frame down tubes. That's, obviously the proper solution and is on my wish-list.
Thanks for any advice.
Steve, in the NLs

Re: Lightening a narrow-case frame for racing

Posted: Sat Oct 03, 2015 6:20 am
by KarstenH
Hello Elmr,

i think the photos can help you, you need a longer swingarmaxle.
The frame is with a usual modifaction for racing.

Karsten

image.jpeg


image.jpeg


image.jpeg

Re: Lightening a narrow-case frame for racing

Posted: Sat Oct 03, 2015 3:39 pm
by ElmrPhD
Thank you Karsten,
I hope to use those pix in the future when I hope to do this mod', but for now...I was just wanting to know what original metal I can remove if I do NOT already have the strengthening mod' in your pix. Sorry, I'm probably not being clear - it was a late night...