For all the tightwads, cheapskates and poorboys...

[racerrad8]

FJ shock spring rate information from Penske. Data in lbs/inch.
Divide by 56 to convert to kg/mm

                          Spring     120-160#      160-190#            190-225#          225-260#
                          Length    with gear       with gear            with gear          with gear
FJ 1100   85-87....... 6..........850...............900.....................950..................1000
FJ 1200   88-89........6..........900...............950....................1000..................1050
FJ 1200   1990.........6..........850...............900......................950..................1000
FJ 1200   91-93........5..........900...............950....................1000..................1050

Man those are stiff springs, that applied a lot of unwanted twisting force to the upper shock mount and cross member which I have seen cracked and twisted open.

The RPM shock, which as most know was specifically designed for the FJ1100/FJ1200, is valved and sprung properly for the FJ. It is not a universal shock that uses a soft valving in the shock to control the oil flow and then must rely on a higher rate spring to control ride height.

I noted a while back while riding an FJ with a Penske shock that the shock, "tops out" which means it travels to full shock extension and then the rear tire starts coming off the ground. If the spring is so stiff and the adjustment is that so the shock can top out under only moderate braking, it really is unsafe.

The reason it is unsafe is the fact once the shock tops out, the rear wheel does not have any pressure holding it to the road. This might be great for kids doing stoppies, but for sport riding it is dangerous.

The top out was one of the hardest things to get tuned out of the RPM shock during the design & testing. The FJ is heavy and there is a lot of weight transfer, so the valving we started with was way off. I am not sure if those who were at the 2012 Renegade rally recall, but that was the issue I was dealing with that day and that was the 4th or 5th version of the valve package. Once that was tuned out of the shock, the final product was read to go and that is what you get today.

I appreciate the fact guys are trying different shock combinations for their FJ's, but if all of the parameters, like swing arm linkage angles, springs rates and internal valving are compromised to accommodate something else; ones safety is that they are taking into their hands.

Ride safe and when you convert over to some form of altered shock combination, make sure you test ride at a graduated pace to make sure something does not sneak up on you that you were not expecting.

I am not say this just because I make a rear shock for the FJ, I say it because I do not want to see anyone get hurt using modified items on their FJ's. We do all of this for "fun" and I think all of us have something important to wake up to everyday; loved ones, family, friends, jobs, retirement compared to being in the hospital or worse, six feet under.

Randy - RPM

[Alf]

I am not say this just because I make a rear shock for the FJ, I say it because I do not want to see anyone get hurt using modified items on their FJ's. We do all of this for "fun" and I think all of us have something important to wake up to everyday; loved ones, family, friends, jobs, retirement compared to being in the hospital or worse, six feet under.

Randy - RPM

It is just that I say to my friends when they speak about "saving" in tyres, pads...

Is it really worth the effort to look for a 2nd hand shock in good nick and take the job of adapt a shock not designed for the dogbones relation, with a damper force dialed for a different spring?

Buy an OE shock (with short dogbones is stiff and unburstable), repair the OE unit, buy a Wilbers shock (excellent, but I´ve not checked the fiability) or Randy´s, the only specially designed shock for our bike

EMC, Betor, Hagon, WP or öhlins are not worth the money because sooner or later leak

[Arnie]

Randy,

I don't understand how any change in rear shock valving or springing can affect "top-out".
If there is sufficient braking force to rotate the mass of the bike then the rear will lift off the ground.
If the rebound damping is high, the lift off the ground will be a bit earlier than if the damping is low, but if you have enough force to lift the rear wheel off the ground, it will lift.
How much and how quickly the front suspension compresses will affect this lift off.
How can the rear shock change this?

[racerrad8]

Too stiff of a spring will not allow the shock to "sag" to the proper level of the shock travel, and already be at or near the full extended position (top out). So the shock already starts at or near the top of the stroke and has all of the compression stoke it could ever use, but the spring to allow that to happen.

Also if the dampening of the shock is too weak, it will allow the piston to travel through the oil too quickly and cause the shock to top out. That was what we have to dial out of the RPM after the shock was set to the dyno numbers the Penske offered up as a starting point.

If the dampening is too high (stiff) then the shock will not top out but it will unload the rear wheel and cause it to get light, but the suspension will keep traveling downward towards the roadway. Whereas a shock that is "topped out" has no more rebound travel in it and that means it will lift the wheel.

Sure, every shock, including the stock shock will reach top out/maximum travel and cause wheel lift, but when the Penske on the bike I was referring to, is sprung so stiff that when you sit on the bike it barely sags, then the shock is at or near top out. A softer spring will help this issue, but the valving inside the shock is set up for use with the stiff spring and if you go lighter then the compression valving is too soft and the ride quality drops off as the shock now bottoms out.

The Penske is a good product and has a track record of being a better product than the stock shock, but the shock has always been a universal product adapted to work on the FJ; not offer the optimum performance for the FJ. Plus, that was really the only option as well and it is head & shoulders better than stock.

It is a balance between the spring & valving. If the valving is compromised to give a better ride, which is how the Penske is done, then they have to use the spring to keep the shock from bottoming out on compression and the dampening is not really working because the shock is already basically topped out because of the stiff spring. Based on the spring offering George posted up, the softest spring is the stiffest spring offered for the RPM shock and that is for 275# plus riders or two up.

All shocks are a compromise, unless you have access to the patented design of the RPM shock with the inertia bypass valving, which now gives the shock a dual valve and offers the optimum ride for the FJ. Then a softer spring can be used to make sure the shock is in the centered range of travel and can perform as designed. The valving has been explained many times regarding the RPM rear shock and this is not the topic for that discussion.

Randy - RPM

[movenon]

The information I posted was just for information as to what Penske has on there spring rates for others to evaluate. Hard to find published data on the spring rates. Internet rumors aside.

Also I noted that Yamaha 1992 service guide pg 4, stock spring rate 13.5 kg/mm (a little over 750 lb/inch). 

Reference Yamaha Service Guides; Rear shock spring rates.
FJ 1200 S/SC   17 kg/mm     (952 lb)
FJ 1200 W/WC  20 kg/mm    (1120 LB)
FJ 1200 B/BC    13.5 kg/mm  (756 lb)

Gets confusing.....

But what ever spring rate anyone uses, in the end it has to balance with the front end and that is reflected in the sag measurements. You have to adjust the spring rate accordingly.  If you sit on a bike and you don't have enough sag then the spring is to stiff,  if you have to much sag then it is to soft. In either of those cases the shock isn't set up for you and a new spring (or shock) is in order.  In choosing a correct spring rate for any one person without a dozen springs on your shelf and time to test ride it becomes a "WAG".  The above information adds to the "WAG" factor that's all.

I have a 14.7 kg/mm rear spring and weigh 212-220 lbs + top box, tank bag etc. and at present I am out of balance (to much rear sag). I am going up to a 16 kg/mm spring (my WAG) and if that's to stiff then it will end up on e bay and I will adjust accordingly.  But in the end my bike will balance. Then I will adjust damping as needed.

IMO choosing a shock to modify it helps to select a shock that you can modify the internal damping if needed. Rebuilding some of the newer performance shocks is no more difficult than rebuilding your forks. Not going to go into what the best shock is because I don't have to foggiest idea. I would think that the RPM shock fits that bill because it is tuned and set up specifically for the FJ. "Plug and Play" so to speak.  As just opinion I would also recommend RPM's fork valves with the springs they recommend to keep things in balance. 
George

[Mike Ramos]

Good evening everyone,

I have been using the RPM shock for a considerable length of time and many miles.  Throughout this period there has not been any degradation in the performance of the shock that can be determined.  The performance remains unsurpassed by any other shock - is there one that can match it?  Perhaps but doubtful.

I carry 11 gallons of fuel, and often fuel up a full ten gallons.  That is a significant amount of weight (much of it directly over the rear wheel) to add without making any changes in suspension settings and more importantly, there is no noticeable difference in handling characteristics; regardless if on a back country road or the interstate.  

At times soft luggage is used as well, yet I never bother with suspension settings - even the ride height is unaffected - the vaunted sag settings are practically unchanged.  Ride quality remains constant with or without the added weight at the same exact settings.

Although [admittedly rather rotund for my short height] at 230 lbs. with full riding gear, add the fuel, the tank bag & soft luggage the RPM shock is fitted with a soft spring (as compared to other shocks) and yet fully loaded or just with the rider the suspension performs remarkably well and the preload remains the same.

I rode to the ECFR in September logging over 6000 miles round trip, riding every kind of Interstate and secondary road imaginable and never changed the settings.  Road the Dragon & Cherohola without the added weight (leaving the baggage in the cabin).  I spent last weekend in San Diego and the mountains.  A month or so ago I spent the day chasing around with Flynt and friends at a mini Renegade Rally in northern California.  In between all that there has been a lot of additional miles.

Which leads to another (perhaps not previously addressed) aspect of the RPM suspension: the increase in tire life.
I am changing out my tires at 12,000 + miles - the set I had for the above travels I was using the soft compound Michelin Pilot Power 3.  While there was still life left in them I have recently installed Pilot Road 3's for the winter riding.  Prior to using the components offered by the gentleman from RPM, tires were worn out at a considerably faster rate, especially the front which often would wear unevenly.  

For all around ride quality, both spirited back country riding and extended cross country Interstate cruising the suspension from RPM is a great combination.

Speaking of balance: there is a particular zone previously described as a "harmonic window" where the ride rivals anything else on two wheels.

Happy New Year, ride safe & keep smiling,

Mike Ramos.

[Dan Filetti]

Good evening everyone,

I have been using the RPM shock for a considerable length of time and many miles.  Throughout this period there has not been any degradation in the performance of the shock that can be determined.  The performance remains unsurpassed by any other shock - is there one that can match it?  Perhaps but doubtful. <snip>

Nice report Mike.  Randy's new shock sounds like a winner, and perhaps the definitive way to optimize the suspension of the FJ. A couple of questions: Would you mind taking a stab at more specifically, how many miles, and how long?  Also, regarding your extended tire wear, I forget, do you also have the RPM Valves up front, or something else?  I did not go back through the thread so that second answer may well be there.

I am not going to be one to consider this shock, my FJ is long dead, but I have been watching the progress of this shock with anticipation nonetheless.

Dan   

[racerrad8]

A couple of questions: Would you mind taking a stab at more specifically, how many miles, and how long?  Also, regarding your extended tire wear, I forget, do you also have the RPM Valves up front, or something else?  I did not go back through the thread so that second answer may well be there.

Well, Mike received the second shock ever made when the testing process started. He has put over 25K on the rear shock in a multitude of different valving settings as well as spring rates.

Yes, he does have the RPM fork valves too which were also tested and variety of ways as well. He probably has close to 35-40K on the front fork valves.

I do believe the rear shock has only just now changed over to the third tire and was changed more due to tread design that were as he lives in a snowy region and he wanted to make sure he had plenty of grip.

I am sure he will come along later with more details.

Randy - RPM

[Pat Conlon]

........just now changed over to the third tire and was changed more due to tread design that were as he lives in a snowy region and he wanted to make sure he had plenty of grip.......

So Mike's running studded snow tires? It figures.....

...my son reported seeing a '92 rolling thru a blizzard at the top of I-80 by Truckee.....

He called me all excited..."Dad...What kind of crazy people do you have on that FJ forum?

Yea, it figures...

[Mike Ramos]

Good evening everyone,

Pat, let's not forget that you were one of the fellows who recommended the PR 3's to me!  Next you proclaimed to me that '92 is the best year for FJ's and then you tell me mine is "okay" but not as nice as yours...  Now you insinuate that I am crazy?  Well I am here to tell you that I deeply represent that remark!

That being said, if it was Thursday evening and not I-80 but Hwy 36 between Red Bluff and Fortuna in far northern California it would have been me whom your son noticed.  It had snowed several weeks ago to the valley floor in the Redding area but the snow soon melted away.  

Thursday afternoon I left Redding about two hours before dark heading to the Bay Area for the weekend and thought first traveling west on Hwy 36 would be a lot of fun - and it was for an hour or so and it was just great riding UNTIL I entered & climbed into the mountains and hit the still existing left over snow, mud, falling rock and especially the gravel that is put down which is good for the autos but not so good for the motorcycles....!

So Pat, arriving in Fortuna and Hwy 101 I had high regard for you and your guiding me to the proper wet weather tires, stopping only for fuel before heading south.  Luckily for all of us out on the left coast the temperatures never reached freezing (so no studded tires needed) and I proceeded south into the Bay Area.

Now on a serious note.  Dan re: the rear shock from RPM - I have over 25,000 miles on the shock in about 14 months.  Initially on the 1991 and these last 16,000 or so on the 1992  (when I purchased the '92 I switched over all the mods from the '91) with the same exceptional results.  

I notice that the gentleman from RPM has speculated that I have "35-40K" on the fork valves.  No, I would say at least double + - considering it was one of my first mods from RPM.

Decreased tire wear has not been happenstance however it has been a most welcome surprise.  Although, like oil we all know what are the best tires for the old FJ (!), I lean towards Michelin and to date the RPM shock has seen a set of Pilot Road 2, two Pilot Power 3's and now at over 25,000 additional miles the Pilot Road 3 for the winter.  In all instances each set still had miles left in them but as I was going on a cross country I changed them out for fresh tires.

Have fun everyone, keep smiling & ride carefully,

Mike Ramos

[clarification from moderator - the Midget intended to express his dissatisfaction with Mr. Conlon's statement about him being of unsound mind - aka "crazy"; the remark is not "deeply represented" but "deeply resented"...]

   

[Flynt]

hit the still existing left over snow, mud, falling rock and especially the gravel...

...and for me the sand.  I was out on the Hyper (PR3 F&R) three weeks back and found patches of ice, snow, sand, gravel, branches, etc all over the road between Mt Hamilton and Livermore.  Stopped at The Junction (halfway to Livermore) and found I was covered in dried on grey slurry from the kicked up mess that had me looking like a ghost.  Massive clean-up job after that, but at least I got through it.  Riding on ice I just took it slow and the bike tracked like a charm...  I think the tires are pretty amazing giving me a fun ride on that day.

Frank

[Flynt]

[clarification from moderator - the Midget intended to express his dissatisfaction with Mr. Conlon's statement about him being of unsound mind - aka "crazy"; the remark is not "deeply represented" but "deeply resented"...]

Agressive passive agressive?   

[Country Joe]

Does any one have an optimal rear sag number for the FJ? I'm looking for 25-30 mm but if anybody has a different number I'm all ears.

Joe

[movenon]

Does any one have an optimal rear sag number for the FJ? I'm looking for 25-30 mm but if anybody has a different number I'm all ears.

Joe

I don't know if there is an "optimal".  What kind of riding do you want to set up for?  Also what is your front sag?  25mm seems pretty tight on the rear for street use to me. You don't want your rear sag to far off from your front.  I am sure there is a spec range for a stock FJ but I haven't found it yet. Keep up the good work. Standing by for opinions  
George

For me (as my bike has been totally changed) I will target 40 - 50mm up front and 40mm the rear. And see what my free sag measures. That's roughly based on the FJ front fork travel of 5.9" (150mm) and rear shock travel of 4.7 " (119mm).  But that's me and I don't do track days or aggressive riding.
George

[Country Joe]

George,
I appreciate your thoughts. I will most likely drop back to the stock Goldwing spring if I want to get maximum sag and work up from there. I will start testing with as much sag as I can get in the rear, as I still have the stock springs in front with slightly longer spacers than stock. I don't remember how much longer they are, but I am not getting coil bind, I still have full fork travel according to a zip tie. I need to start writing this stuff down...........don't expect any testing for a while, work has me out of town quite a bit this month and the weather is going to be, well, variable.

   Joe