FJ1100 - Raising the rear end with shorter dog bones

[Tools99]

Is there a set of dog bones from another bike that are direct swap and offer a 2" lift at the rear?
I'm keen to raise it up a bit and wated to know what others have done..

Cheers

[aviationfred]

The 1100 has a scissor style shock linkage. There are no dog bones.

If your 1100 has been modified with a later model 1200 swingarm. You can fabricate shorter dog bones for your desired height, or use Soupys adjustable dog bones.

https://www.ebay.com.au/itm/183420326524?hash=item2ab4b4127c:g:Z6QAAOSw-7tg94~a


Fred

[Dads_FJ]

I installed a Honda F4 shock on my 1100 which increased the rear travel.

https://www.fjowners.com/index.php?topic=6549.15

[Pat Conlon]

Robert, will the new RPM shock be height adjustable for the '84 to '87 FJ's?

[Sparky84]

Option of a longer eye would be nice.

[RPM - Robert]

Not at the moment. The shock designer only has them made up for the 89-90 as of now.

[Greenlander]

I installed a Honda F4 shock on my 1100 which increased the rear travel

I also did the Honda F4 conversion on my 84 FJ and it noticeably improved my front wheel grip when cornering and consequently improved front tire wear as well. Probably the least costly way to raise the rear end. I think I paid $60 for the F4 on eBay. There is a very well presented F4 conversion in the modification files section which made it a lot easier

[ZOA NOM]

Wouldn't recommend adjustable dog bones. That's not a place for a weak piece.

[Millietant]

I would normally agree, but Fred and others have done many thousands of miles on their FJ's with Soupy's adjustable dog bones, without issue.

[Pat Conlon]

I have ~40k on my Soupy's and they are fine.....but I agree with Rick. I don't recommend them.
It's not because they are weak.
It's because you have to set each side "dead nuts even" or you will tweak the linkage bearings in your swing arm. You can not get this type of tolerance by adjusting them on the bike. The threads are too course.
I do the final adjustment on a jig where I can get proper accuracy when I snug down the lock nuts.

When you fabricate your own dog bones out of strap steel, you clamp both pieces together when you drill the holes, so we know those holes are even.

[ribbert]

Wouldn't recommend adjustable dog bones. That's not a place for a weak piece.

"I agree entirely with that, mostly for the reason Pat points out, the near impossibility of adjusting them dead even and the subsequent excessive load, accelerated wear etc and the fact the engineering is all wrong. I could not in good conscience recommend them as a permanent fitting. I have seen them used to find the right length then use that measurement to make fixed ones, after all, who changes them after that anyway.

Not having had a failure does not in itself make it a good design.

Pat, didn't you prematurely wear something out from uneven adjustment?

And then there's this FJ.......



...look at the design, you could bet the house where that was going to break."

[Pat Conlon]

Yes, I speak from experience.  I learned the hard way.
In the picture you posted above, see the 5 difference faces of turnbuckle nut on the Soupy dog bone?
I was worried about my ham fisted uneven adjustment so I stamped each face of the turnbuckle nut with a number. Using a reference point on the frame, I made sure the correct number lined up on each side, before I locked it in.......Still not good enough....A millimeter or two off in the length between links will tweak your needle bearings.

Tim (Axiom R) had a failure of a single Soupy dog bone on his R-1 swingarm conversion.
In that case, yes, a single Soupy was too weak. My double Soupy's are holding up fine (so far)

However....Now that I've said that.....

Don't get adjustable dog bones, you don't need them.
What length do you need for your bones?
With the bike on the center stand, disconnect the linkage, put a piece of 3/4" plywood under your back tire and measure for the length of the new dog bones. Clamp them together when you drill the 10mm mounting holes.

Call it a day, keep it simple. I'll bet you a jelly donut you will find the new height perfect.
It will be so much better than the stock height, especially with a 30+ year old sacked out oem shock.

[ZOA NOM]

Mainly, they are easy to fabricate so I don't see the value in adjustability.

If I recall, about 115mm length, center - to - center was an ideal length for a nice ride height.

[ribbert]

....A millimeter or two off in the length between links will tweak your needle bearings.

"Pat, I think you're being generous allowing even 1-2mm.

As for that failure in the photo being a single Soupy, that's exactly what a pair becomes when the adjustment is uneven, all the load shifts to just one. Given that failure would be instantaneous, without warning, total and catastrophic, and it's not even a risk that has any reward, I see no point. There are Rose joints with more of a taper that would be stronger, but once again, why bother.

Haha, anyone familiar with this process .....



.....knows that nipping up the locknut always changes the setting.

As Rick, Pat and others have said, once a length has been determined, adjustability is no longer necessary or even an advantage.

I go one step further than Pat when making linkages, I tack them together until they're finished."

Source: Fjowners Forum

[T Legg]

Haha, anyone familiar with this process .....



.....knows that nipping up the locknut always changes the setting.

 I remember the first time I had to adjust the valve shims on my cb900f . I was intimidated. As a current owner of Volkswagen's , a 92 Toyota truck, and several cb 750's  I still prefer adjusting valve tappets to changing shims.