Rear arm change

[bartha32]

Hi, I'm slowly progressing in building my bike. I've started it 5 years ago,hopefully this summer i'll finally be able to ride it. Unfortunately the landing gear is in bad condition, so I'd built in the back swing arm and rear shock absorber from 1991. I had already had them, so I thought I'd try it. Their position isn't like the original 1100 ones' but like the one on the picture.
Something i've noticed is that the center stand is touching the dog bone's screws when bent up and the drive chain is touching the inside of the silencer. I think i will remove the center stand and the lack of it won't bother me. The chain won't touch the exhaust, becouse the back swing arm is never fully open while riding. My question is: Could this cause any problem or damage anywhere, or ruin the bike's manouverability? So far the 1100 engine has got an 1200 crankshaft, con rod, piston, cylinder&head. New piston ring, all bearings, seal. 1991 front fork&wheel, Fjr silver  brake.The green sketch on the picture is the 1100's original parts' position. The red is where the center stand touches the dog bone. The sizes difference is about 30-40 mm, which I think is caused by that the shock's upper screw is lower on this 1100 than on the 1200.thanks in advance. Hope i get reassuring answers. Bye.

[bartha32]

Hi, I'm slowly progressing in building my bike. I've started it 5 years ago,hopefully this summer i'll finally be able to ride it. Unfortunately the landing gear is in bad condition, so I'd built in the back swing arm and rear shock absorber from 1991. I had already had them, so I thought I'd try it. Their position isn't like the original 1100 ones' but like the one on the picture.
Something i've noticed is that the center stand is touching the dog bone's screws when bent up and the drive chain is touching the inside of the silencer. I think i will remove the center stand and the lack of it won't bother me. The chain won't touch the exhaust, becouse the back swing arm is never fully open while riding. My question is: Could this cause any problem or damage anywhere, or ruin the bike's manouverability? So far the 1100 engine has got an 1200 crankshaft, con rod, piston, cylinder&head. New piston ring, all bearings, seal. 1991 front fork&wheel, Fjr silver  brake.The green sketch on the picture is the 1100's original parts' position. The red is where the center stand touches the dog bone. The sizes difference is about 30-40 mm, which I think is caused by that the shock's upper screw is lower on this 1100 than on the 1200.thanks in advance. Hope i get reassuring answers. Bye.

[Pat Conlon]

Your mistake is using a shock and linkage off a late model FJ on a early FJ and expecting the linkage geometry to work out.....It does not as you see, the top mounting point for the shock on the frames are different.

Here are 2 problems and 2 solutions.
1) Your relay arm is at too steep of an angle. You need a shorter shock, about 1" shorter should do it.
Get a shock that has adjustable shaft length for fine tuning.

2) Now with the shorter shock, you can reduce the length of those dog bones (links) to clear your center stand.
With the bike on the center stand, shock linkage disconnected, rest the tire on the ground, now slip in a piece of plywood between the ground and your back tire, now measure the length for your dog bones.
When you make your new dog bones, it is *critical* the the holes in the links line up perfectly....uneven holes will cause uneven loading on the linkage bearings and shorten the life of those bearings...don't ask me how I know this.
Therefore, when you drill the holes in the dog bones (links) use a vice, squeeze them tight, and drill both links at the same time so the holes match.

Cheers

Pat

[FJ1200W]

Your mistake is using a shock and linkage off a late model FJ on a early FJ and expecting the linkage geometry to work out.....It does not as you see, the top mounting point for the shock on the frames are different.

Here are 2 problems and 2 solutions.
1) Your relay arm is at too steep of an angle. You need a shorter shock, about 1" shorter should do it.
Get a shock that has adjustable shaft length for fine tuning.

2) Now with the shorter shock, you can reduce the length of those dog bones (links) to clear your center stand.
With the bike on the center stand, shock linkage disconnected, rest the tire on the ground, now slip in a piece of plywood between the ground and your back tire, now measure the length for your dog bones.
When you make your new dog bones, it is *critical* the the holes in the links line up perfectly....uneven holes will cause uneven loading on the linkage bearings and shorten the life of those bearings...don't ask me how I know this.
Therefore, when you drill the holes in the dog bones (links) use a vice, squeeze them tight, and drill both links at the same time so the holes match.

Cheers

Pat

You are the man!

[Pat Conlon]

It is important to note that starting in 1991 Yamaha offset the shock to allow for clearance for the ABS pump.
This off set was at each end of the shock, at the top frame mount and on the lower shock mount on the relay arm.
Remember that the '84-'90 FJ's had center mounted shocks.....the shock offset started in '91.

Therefore...

If you use a relay arm on your early FJ, you do not want to use the offset relay arm from the '91-'95 FJ.

You want to use the relay arm off the 89/90 FJ that has the shock centered. This centered lower relay arm will line up with your existing centered top shock mount.  On the shock shaft itself, the lower mount on the early FJ's is an eye mount and on the lower shock shaft for the later shocks is a clevis mount.....so, you will need a shock with the clevis lower mount to use with the relay arm linkage.

Here are some side by side pictures of the difference between the shock centered 89/90 and the shock offset 91/95 relay arms. The '91/95 is the silver colored.....sorry for the dark pictures.

[andyoutandabout]

Well that's another interesting factoid about my ABS bike.
This is like the online learning so many students are now involved with nationwide, except I'm paying attention

[FJ_Hooligan]

And not incurring any student debt.

[andyoutandabout]

Yep, in reality probably saving money at some point.
It's safe to say that the Fj has provided much bang for the buck.
With this forum, ownership experience has proved greater than the sum of its parts.

[bartha32]

Thanks for the advices, it has helped a lot! I've got 1100 parts in good condition, it works well. Thanks to everyone!