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Do whatever you feel like.
#1 it doesnt sound like u are interested in the warnings from the group
#2 it's the subframe, as long as you arent 300 pounds or your girlfriend/boyfriend isn't, anything reasonable as support other than a simple cantilevered loop should do fine. The subframe does add some structural support to the main frame, but if you are welding, i would throw some well placed frame bracing in there at the same time.


You see the issue here is by your questions you reveal your general lack of mechanical knowledge. No offense, but it's like a regular joe asking at a doctors conference if he should remove an appendix by an up and down incision or a sideways incision.
 

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Thanks for the advise ill do the minimum
View attachment 97719
If that's your frame, it looks plenty beefy to me...

OK maybe I was a little premature with the whatever comment. Look where your monoshock mounts to.
You need to make sure that is as well braced as original or you WILL have issues.

Going out for a ride right now, but I will compare the pics when I get back...
 

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Discussion Starter #24 (Edited)
so i cut of the unwanted part and left the top bar to the length i require have to shorten it to include the hoop. after having space n a being able to see how the rear swing arm n suspension work i came up with 3 options again lol.

1. would be to just put a supporting bar extending the existing bottom bar to the middle of the seat option
option1 build.jpg

2. would be to use bars but totally eliminating the existing bottom bar and creating a new one like the xj600 design and putting a bar across (blue bar) the top of the shock mount to give it that extra strength
option2 build.jpg
option2 build2.jpg

3. would be the same as option 2 but instead of using round bars i would use 5mm thick plate to create the support. Sort of the the xj600 major lazer by wretch kings. of course my will have a bigger plate but similar concept. Making sort of a box with thick plate and using the bottom plate (blue plate) of the box to reinforce the top mount of the shock
Of course the side plate n bottom plate would extend to make the seat base
option build plate.jpg
Yamaha_xj600_bigs_03.jpg
Yamaha_xj600_bigs_09.jpg
 

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Ok, so ideally you should have cut the frame with the weight off the rear shock. Even cut and weld with the frame in some kind of frame jig.

This thread is a whole bunch of fail...

I suspect when you cut it the frame went boooooiiiiingggg and the upper shock mount moved. Thats just changed critical geometry points on the bike.

These are things you just should know before starting...
 

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Discussion Starter #26
Ok, so ideally you should have cut the frame with the weight off the rear shock. Even cut and weld with the frame in some kind of frame jig.

This thread is a whole bunch of fail...

I suspect when you cut it the frame went boooooiiiiingggg and the upper shock mount moved. Thats just changed critical geometry
points on the bike.

These are things you just should know before starting...
No the top of the shock is still secured in the bottom frame I have not cut the frame top mount supports. I have edited the pictures to show no support.
 

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Courage is knowing it might hurt, and doing it anyway.

Stupidity is the same...

...and that is why life is hard.


I'm out. Let us know when the "for sale" ad is posted of the unfinished project
 

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Discussion Starter #28
I have not cut the supports for the shock I only edited the pic. I will finish it and won't be for sale. I'll let you guys know it goes

IMG_20190505_224440.jpg
 

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you need to support those two tubes you cut the tops off, as they provide the rear support to the top shock mount. that plate will need some structure under it at least. the way it was would have been the most effective strength vs weight vs packaging wise.
 

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I have not cut the supports for the shock I only edited the pic. I will finish it and won't be for sale. I'll let you guys know it goes

View attachment 97769
What I believe they are trying to tell you is that the tubes that you cut off were what was holding the frame and shock mount in square. The proper way to modify a structural member is to put your new stuff in before cutting off the old so that the frame doesn't torque out of place when you cut off the old. To demonstrate this, if the piece you cut off is still in one piece see if it would line up if you wanted to weld it back in place. I've got no motorcycle frame experience, but that is what you would need to do before modifying a truck frame.

At a minimum you need to tie those cut tubes into your structure above so that when you hit a bump it doesn't rip that shock mount off or just bend the whole upper works upward.
 

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Discussion Starter #32
Okay i just work differently. so im going to remove totally the top bar and bottom bar and move the shock on the top of the swing arm like in the XJ600 s-l1600 (2).jpg
weld the shock top mount under the tank. might need to change the shock depending on the distance i need
 

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Discussion Starter #33
i hope this makes sense to you all n im on the right path. would like to know would the stock do or can i use the XJ600 rear shock

xj with shock mod.jpg
 

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Discussion Starter #38
Yes 600 is chain drive and my is shaft i will not be changing the swing Arm but simply creating the same style shock mount to be able to mount the shock on top of my swing arm.
shock move.jpg
 

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Is this your real live bike and does it have a linkage type monoshock suspension?
& is your plan to turn it into an inferior non-linkage type suspension?
if yes ... that's a really bad idea dude :|
I don't believe the OP will have any idea what your talking about.
 
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