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motorcycle frame bracing

Posted: Thu Aug 14, 2014 1:36 pm
by jcw
I have a new respect for people that fit tube up for welding. These 4 tubes took almost a week of cutting and grinding and cursing and throwing away and starting over.

Fit up looks good for three corners and OK for one. It's bad at one of the center tube joints.

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Next up cleaning and tacking and tigging
Wish me luck...

Re: motorcycle frame bracing

Posted: Thu Aug 14, 2014 1:38 pm
by jcw
Suggestions are welcome!!! ;)

Re: motorcycle frame bracing

Posted: Thu Aug 14, 2014 2:24 pm
by danielbuck
If I were going to be doing a significant mount of tubing work in one or two sizes, I'd probably pick up one of these! Looks like they would remove alot of guess work.

I'm contemplating picking one up (or seeing if I can borrow one from someone) when I start on the cage for my jeep, some of it is already prebent and cut, but I'm going to be adding on some additional tubing, I bet it's worth the price for the time and frustration that it probably saves.

http://www.pipemastertools.com/viewall.html

Re: motorcycle frame bracing

Posted: Fri Aug 15, 2014 1:53 am
by jcw
Cool tool. I know I've seen that before but never crossed my mind. It would have been very helpful.

Here's the crossbrace tacked and then welded together on the bench. These were the joints with the worst fit up and they came out OK considering...

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Re: motorcycle frame bracing

Posted: Fri Aug 15, 2014 4:37 am
by dhc4ever
Is that a yamaha XS 750 triple?

And what do you have planned for the frame aft of the rear shocks?

Re: motorcycle frame bracing

Posted: Fri Aug 15, 2014 10:21 am
by jcw
Yes. XS750 with a XS850 engine rebuilt with higher compression xs1100 pistons, undercut trans, new rods, polished crank, eventually a ported head. Busa front forks and triple. Fun project going on one year.

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I don't know what to do with the rear. The braced frames I've seen don't seem to address it. I'm wondering if it matters less because it doesn't effect geometry as much as long as the swinarm pivots to the steering head maintain the correct geometry.

Believe it or not, those tubes went on for about 6 more inches then terminated. a rear cowl with grab-bar and fender bolted to the rear. I was thinking maybe some simple gussets as long and it clears the rear tire.

What do you think?

Re: motorcycle frame bracing

Posted: Sat Aug 16, 2014 9:11 pm
by dhc4ever
Is this going to be used on the road?
It will need a rear mudguard and somewhere to hang lights / indicators from.
If not a fibreglass rear cowl over the rear tyre should keep it within your minimalist approach.
I quite like the look of this one;
http://astraone.com/yamaha-xs-750/cafe-racer-33/
Theres a few other photos on tha site for ideas as well.
Are you going to brace the rear swingarm? I have vague memories of a couple of old xs 1100's having that in an attempt to stop the high speed wallow they had, typical 1970' japanese issue, great engines, spaghetti frames, average brakes.

Re: motorcycle frame bracing

Posted: Mon Aug 18, 2014 12:39 am
by jcw
Well, searching the net hasn't yielded much on what to do with the front so I built this.

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Not exact, but close enough to give me an idea where would be the best to brace the head stock.

Re: motorcycle frame bracing

Posted: Thu Aug 21, 2014 2:16 pm
by xwrench
You do very nice looking work. That Pipemaster is a very cool tool. I know what I'm saving up for next :D

Re: motorcycle frame bracing

Posted: Thu Aug 21, 2014 4:40 pm
by AndersK
Here's a link to a free software that layout the profile so it can be printed and then wrapped around the pipe.

http://sheldonbrown.com/rinard/tubemiter.exe

Instructions here (scroll down to Software):
http://sheldonbrown.com/rinard/framebuild.htm