Rear wheel conversion, or RPM fork valves

[ELIMINATOR]

I have just fitted a 16" Avon Storm 3DXM to mine.

[jvb_ca]

Do the front end with Randy's RPM fork valves. You will not be disappointed.

http://www.fjowners.com/index.php?topic=9670.msg92044#msg92044

Cheers...Jake

[FJscott]

To my way of thinking, it's most important to keep whatever rubber you have in the best contact with the road.  I would (and have) put suspension well ahead of wider tires.  Straight-rate springs, fork valves and a proper rear shock will make your bike feel more "planted" on the road.  After that, think about your best path to fat tires.

+1 on the suspension first. I have Randy's fork mod and shock. I was very happy with the handling at the Central Rally twisties in the Ozarks riding on 16" wheels. I am running Avon Azaro radials and am happy with their performance and longevity. Unfortunately I have just received another 16" rear tire and understand Avon is discontinuing the 16" Azaro. I might be forced to find 17" wheels. Dave 

Could not agree more. if its an Either or decision suspension or wheels, suspension would be my priority with the front having priority over the rear.

when I did my 92 I did the front first;
blue dots
rotors
ss braided lines
RPM valves
.85 race tech straight rate springs
3.5" wide front wheel
and I did it all at the same time, I just wanted it done. part of me wishes I had done it in stages to see how the improvements affected the handling in progression. EG... forks, then brakes, then fatter rubber...

when I did the rear, again I did it all at once;

FZ1 swingarm, FZ1 shock, FZ1 blue dot, 5.5" wheel with 180 conti-motions. I raised the ass end 2inches but did it by welding a new upper shock mount instead of doing it with dog bones. I wanted to keep the shock linkage geometry as Mr Yamaha designed it.

My FJ is officially done... now my XR650 is scratching my Moditus itch

Scott

[ELIMINATOR]

Just ordered the bits from Randy.............. well, it is The Black Friday sale

[FJools]

Hi

Newbie here - this is my second post !

I was drawn to this topic straight away 

I picked up my '92 FJ1200 yesterday and although it has a race tech front end, my first consideration is replacing this with some 43mm R6 triples, forks and blue spots I have lying around. I first need to measure axle to fork tops in the extended position to see how close they are.

It already has EBC rotors on the front but the brakes don't seem to have much initial feel.

Then the rear shock, which is probably original. What do you guys recommend? - bearing in mind I'll probably go 17" at the same time. Any tyre clearance issues ?

Jools

[FJmonkey]

Then the rear shock, which is probably original. What do you guys recommend? - bearing in mind I'll probably go 17" at the same time. Any tyre clearance issues ?

Jools

Many of us have posted up on 17" conversions for the front and rear. If ya go to a 5.5 inch wide rear then you will get mixed results on a 180 wide tire clearing the chain. I run the Continental Motion combination and the rear clears the chain with a few MM to spare. When I ran the Dunlop Q2 set the chain machined off about 3 to 4 MM of the side of the tire. Not enough to worry about but the side load on the chain might reduce the chain life. Poke around, lots of good info already posted. If you get lost then holler for help....

Rear shock you ask? Many good options. I chose the RPM rear shock after installing the RPM fork valves. Awesome product, made my FJ feel like a new machine.... The fork valves have made my FJ and I faster in the corners, they are so smooth now...

[FJools]

I just finished reading the link to the UK site (?)

There seem a lot of options for the rear conversion but I might go with the simpler option of a new shock until this new rear Pirelli wears out.

The main reason for going to the R6 front end is because the std 41mm FJ forks will go nicely in my Period 5 CMR chassis for my TZ750 race bike, which needs a better chassis and 17" wheels to be competitive these days. I bought the R6 items thinking they were 41mm, but they are of course 43mm so can't be used - neither could the blue spot callipers.

[FJools]

How different is the 86 - 87 rear shock from the 92 ?

[FJmonkey]

How different is the 86 - 87 rear shock from the 92 ?

Here is my stock 84/87 shock next to the RPM 89+ shock:





I did not take any measurements of the difference, you will have to take a swag at the approximate difference. I am guessing about 0.75 of an inch.

[movenon]

A question Mark, When you look at the front cross member of the swing arm (the area behind the shock spring) do you have clearance between the spring coil and that cross member under load?  Any signs of rubbing or binding on the swing arm cross member ?

I do not run the RPM shock but have a shock of similar dimensions as yours the coil bottom is lower than the stock FJ spring was and initially when I installed it with raised dog bones when I sat on it (under load) then it would impact/rub slightly against the swing arm cross member.  The fix for me was to adjust the dog bones now I have a few mm of clearance. My rear end is still approx 3/4-1 inch higher than stock. My problem was that my dog bones were to long for where the new spring was located.  It did take some fine tuning of the dog bones.

I was just looking at your photo's remembered a problem I had with a slightly longer shock with the spring mounted lower.  
George

[FJmonkey]

George, you ask a good question. I am breaching uncharted territory in my quest for dog bones on my 86'. I have some miles on my 86' with the 89+ shock and longer than expected dog bones. I found that I cannot have my center stand (CS) installed, it is held/pushed down low enough that I could lean over and hit the CS and lose control under normal riding conditions. I was lucky to discover this before my recent ride with Cap'n Ron and Simi_Ed. I am sure Ed has cleaned and repainted my CS by now. I will get a ratchet strap and compress the rear to make sure the current configuration will not hit any unexpected hard stops. As it is I am riding with caution, I have made changes and that alone is cause for caution. And the changes are beyond the OEM intended geometry so things could go really wonky. The current set up feels better than the sacked out OEM shock so I am happy to be putting the miles and smiles on the SoCal roads this season... 

[FJools]

The reason I asked was that looking at Ohlins shocks (just looking -= honestly!)

They list different types for:

1986 - 87
1988 - 90
1991 - 93

But without listing the differences. Makes it hard to work out if an earlier shock will still fit the later bike, taking in to account the latest replies of course.

[FJscott]

Hey Mark,

when I was installing my FZ1 arm and shock I thought I would need some adjustable dogbones. I ended up making a new top shock mount and keeping the stock doggies on the link arm. you are welcome to the adjustables if you want them. Ill be home first of jan.

Scott

[movenon]

George, you ask a good question. I am breaching uncharted territory in my quest for dog bones on my 86'. I have some miles on my 86' with the 89+ shock and longer than expected dog bones. I found that I cannot have my center stand (CS) installed, it is held/pushed down low enough that I could lean over and hit the CS and lose control under normal riding conditions. I was lucky to discover this before my recent ride with Cap'n Ron and Simi_Ed. I am sure Ed has cleaned and repainted my CS by now. I will get a ratchet strap and compress the rear to make sure the current configuration will not hit any unexpected hard stops. As it is I am riding with caution, I have made changes and that alone is cause for caution. And the changes are beyond the OEM intended geometry so things could go really wonky. The current set up feels better than the sacked out OEM shock so I am happy to be putting the miles and smiles on the SoCal roads this season...  

My shock is 290mm center to center of the mounting holes just for info.  My center stand is back on so far no problems dragging but you are a much more proficient rider than I am.  The stand when retracted rests on the muffler stop so I guess it is as it should be.  My current spring diameter might be larger than your also. All I can say is mine is close with the modified dog bones. On mine I could bounce hard on the seat and her something down there squeaking and it didn't feel right. If it is impacting or rubbing against the swing arm cross brace you should see some marks on the cross brace and marks on the back side of the spring.  You are probably OK I am just throwing out what happened to me.

It will be interesting to hear what you find out about the upper mount. I know the 91-93 mounts are higher and offset, they use a shallower but wider battery than the 84-90"s enabling Yamaha to raise the upper mount.
George

[FJmonkey]

Scott, I may be interested in the adjustable bones. That will help me dial things in when I start playing around with any corrections I may need to do. No rush, I am waiting to hear back from Randy after he has had the chance to look at few different years of frames. My bike is ride-able, just pissing rain right now so I will stay inside where it is warm.

George, my CS was held down an inch or more and would not rest on the bumper. Not safe for any skill of rider. Once I get the shock mounted correctly, the CS will fit properly once again.