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FJ1100 - Raising the rear end with shorter dog bones

Started by Tools99, September 16, 2021, 12:32:07 AM

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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
I'm not the fastest FJ rider, I am 'half-fast', the fastest slow guy....

Current
2008 VFR800 RC46 Vtec
1996 VFR750 RC36/2
1990 FJ1300 (1297cc) Casper
1990 VFR750 RC36/1 Minnie
1989 FJ1200 Lazarus, the Streetfighter Project
1985 VF500F RC31 Interceptor

Dads_FJ

John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'92 Yamaha TDM850
'80 BMW R100S/Sidecar
'81 Yamaha IT250(H)
'77 Yamaha IT175(D)
'39 BSA WM20

Pat Conlon

Robert, will the new RPM shock be height adjustable for the '84 to '87 FJ's?
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Sparky84

1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

RPM - Robert

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

Greenlander

Quote from: Dads_FJ on September 16, 2021, 12:05:09 PM
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 :good:
Keep the rubber side down
1975 Harley 250 (Cagiva ) fun but unreliable. Sold After 6 M
1975 Honda CB 550 fun and reliable,sold
1980 Suzuki GS 850 daily driver,weekends.Very dependable. Sold for the FJ in 89
1984 FJ 150K of year round (fun)commute in SoCal

ZOA NOM

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

Current:
2010 Honda VFR1200 DCT (Full Auto!)
1993 FJ/GSXR 1200 (-ABS)
1987 Porsche 911 Carrera (Race)
1988 Porsche Carrera (Street)
Previous:
1993 FJ1200 (FIREBALL)
1993 FJ1200ABS (RIP my collar bone)
1986 FZ750
1984 FJ600
1982 Seca

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. :good2:
Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - complete runner 2024 resto project
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.

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.

1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

ribbert

Quote from: ZOA NOM on September 17, 2021, 03:42:39 AM
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."

"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

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..... :dash2:

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.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

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.
Rick

Current:
2010 Honda VFR1200 DCT (Full Auto!)
1993 FJ/GSXR 1200 (-ABS)
1987 Porsche 911 Carrera (Race)
1988 Porsche Carrera (Street)
Previous:
1993 FJ1200 (FIREBALL)
1993 FJ1200ABS (RIP my collar bone)
1986 FZ750
1984 FJ600
1982 Seca

ribbert

Quote from: Pat Conlon on September 17, 2021, 11:27:19 AM
....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
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

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.

T Legg