rear shock

[racerrad8]

So randy do you have a used rpm shock in great condition in the $500/600 range?

Sorry, no used ones that I am aware of.

Randy - RPM

[yambutt]

Randy what is the length of the 1992 original rear shock, slso I will be ordering your fork valves and springs next month....thanks

[Pat Conlon]

I will concede that that the IAT valving technology is a more modern design***than the tried and true shim stack technology. I will concede that for a stock FJ, using the stock tire sizes, the RPM shock is fine.

**The IAT valving will become last week's news when the new generation ESA shocks will hit the market.

So, getting back to the subject of rear height adjustment, on the '89-93 FJ's Ricor thinks it's fine to alter the dog bones?
It's just that the early FJ's are SOL?

Rim conversions vs Ricor recommendations:

How about the early FJ folks who want to do the 17" rim conversion and have the ability to use modern (read superior) 17" tires in the 180/55 size?

What does Ricor recommend for FJ suspension adjustment to compensate for the smaller diameter tire?
Don't do the conversion? It's not needed?
Modern tire technology has no place on a 30 year old bike?
Lower the front forks?

Where we fundamentally differ is the understanding of adjustability.
You keep saying that the Penske/Hagon/Ohlin shocks are inferior because they can be set up for many different applications. I disagree.....Adjustability is good. The more the better.
I believe the more adjustability a product offers, the wider the application the product can fit.

**It is a tactical error for Ricor to make a $900 shock for our FJ's with no provisions for height adjustment**

Period.

Like I said, IAT valving technology is cool, but the writing is on the wall, it will be superseded by the ESA shocks with push button adjustability (there's that word again: adjustability) when they become available for our bikes.

Want to bet that those ESA shocks will also be height adjustable?

There's that word again.....

[FJmonkey]

Some time back the lengths of all three shocks were posted. Have you tried the search function? Many find Google searches easier when they include "FJowners" in the search line (remove the quotes).

[yambutt]

Think I found it on here, thanks, looks like its 300mm

[simi_ed]

shock length site:fjowners.com

[FJmonkey]

Ed, gonna post up pics of our defiance of El Nino ride? A tad cold but really good weather and riding....

[rktmanfj]

Ed, gonna post up pics of our defiance of El Nino ride? A tad cold but really good weather and riding....

     

[racerrad8]

Nice redirect Pat...

ESA shock for a FJ  

Lets get back to the topic at hand and not worry about the future. I seem to recall a movie made 30 years ago that predicted we would all have flying cars by now, hell even the "hover board" still has wheels...

I will answer the questions I posed to you, plus answer your questions below.

Are you really being serious to tell me they have spent any time with 30 year old FJ specific motorcycle testing? I'll let you answer this one
Did they invest in an FJ and design a shock specifically for the FJ?   NOPE
Did they ask Penske, Hagon, Ohlin or Fox to design a FJ specific shock?   NOPE
Do any of the above manufactures offer any patented technology?   NOPE
Does Penske use it? (IAT technology)   NOPE

I will concede that that the IAT valving technology is a more modern design(*)than the tried and true shim stack technology.
(*)The IAT valving will become last week's news when the new generation ESA shocks will hit the market.

   Do you really think your shock is a "true shim stack shock"? What do you think you are adjusting when you adjust all of those adjustments on your shock? I'll tell you, needle valves in orifice to control oil flow, not the shim stack. (just like your idle mixture screws)

I will concede that for a stock FJ, using the stock tire sizes, the RPM shock is fine.

   How can you concede to something you have no idea what you are talking about, when was the last time you rode a stock FJ with RPM suspension components? Maybe that is the reason for the re-direct to ESA

So, getting back to the subject of rear height adjustment, on the '89-93 FJ's Ricor thinks it's fine to alter the dog bones?

Yes, the rear height adjustment is much better completed after the relay linkage. Just like installing a drop spindle to lower a car or a block to raise or lower the ride height of a leaf spring vehicle; in both of these examples, the ride height is altered but the suspension geometry is not.

   If the relay arm geometry is changed there are leverage issues that come into play that alter the shock valving throughout the stroke. There is a thing called moment of center (similar to TDC & BDC in an engine) and 99% of all shock relay linkages are design to operate on the moment of center. That way no matter what, the up or down movement of the relay arm is on a constant arc, but the shock pivot point gets closer to the pivot above & below the moment of center. This moment of center affects all kinds of things on bikes & cars. Your chain tension with the swing arm down compared to perpendicular to the front sprocket is the best example I think everyone can understand. If the chain is adjusted too tight at rest, when you sit on the bike and the swing arm come closer to level, the chain gets tighter.

   On a car the moment of center applies to both front & rear suspension that affect caster & camber changes through the suspension travel, rear steer in the rear suspension. Shock performance due to angle changes through the suspension travel.

So here is a little theory on changing the relay arm linkage, lets move the relay are down 3/4" with your shock and the relay arm is now at the 7 o'clock position compared to the original 9 o'clock. The leverage it take to come back to the moment of center (9 o'clock in this example) in compression is greater. That is because the leverage of the shock, since it is now not at the moment of center is closer to the actual pivot pivot point. So, you have now increased the leverage required to move the shock, which requires the valving in the shock to be lighter because of the additional require force to move the relay arm to moment of center. Then the linkage arm gets to center and goes over and the shock valving is too soft.

   So, with the Yamaha design, the relay arm is at or near the moment of center (depending on rider weight) and the RPM shock valving can be even and consistent. There is no compromise required in valving to make the shock work properly.

   Now, with your longer Penske shock, you have to adjust the compression of the shock to compensation for the moment of center dependency due to the light shim stack, but hey, you have an adjustable shock.

It's just that the early FJ's are SOL?

In Ricors eyes, raising the rear of the bike is not their issue. They designed a specific shock with all of the linkage geometry in mind, not the end users modified ride height requirements. I started looking at designing a rear portion of the early linkage to raise the rear of the bike, but I looked at investment Vs. return and I am not sure I can ever recover the invest made to change the system. (maybe someday I will manufacture a solution)

Rim conversions vs Ricor recommendations:
   How about the early FJ folks who want to do the 17" rim conversion and have the ability to use modern (read superior) 17" tires in the 180/55 size?

My 86 is running a pilot power 3 in the aforementioned size and I did not notice a difference in the ride height while riding, in fact when I changed over to the RPM shock, the bike was some much quicker due to the back tire actually stay connected to the pavement. Even Monkey Mark says the same thing, he does not feel he is riding any "faster" but his lean angles have increased as well as his speed due to the improved performance of the RPM suspension components.

I cannot vouch for them as I went from a sacked out old OEM shock to the RPM shock. The difference between them is Night and Day. My last ride was a pleasant surprise to me. I found my Chicken Strips reduced by half, I did not feel that I was riding any harder or faster than my normal rate. Having a better shock than OEM allowed this new comfort zone to happen with no intentional input from me.

What does Ricor recommend for FJ suspension adjustment to compensate for the smaller diameter tire?

Again, not their problem, they are a shock manufacture, not a suspension design & manufacturing company (Again, maybe someday I will manufacture a solution)

Don't do the conversion?

They don't care what you do with your wheels, that is not their field of operation; they manufacture shocks.

It's not needed?

Once again, my 86 rides on stock suspension components and I have not had any personal issues. I have also not heard from a single early RPM shock purchaser regarding ride height issues.

Modern tire technology has no place on a 30 year old bike?

Not sure what you mean there, sure we all want the latest & greatest.

Lower the front forks?

Why would you need to do that, because the rear of the bike went down by 1/4"?

Where we fundamentally differ is the understanding of adjustability.

You are right there, I am speaking from knowledge, experience, education & on the job training with both race car and motorcycle suspension systems. So far you have offered the advice of "experts" for which you have received.

You keep saying that the Penske/Hagon/Ohlin shocks are inferior because they can be set up for many different applications. I disagree.....Adjustability is good. The more the better.

I never said any of those shock are "inferior", I am telling you there a universal product that can be bolted onto a variety of motorcycles and they have to provide the adjust-ability to be able to cover all of the differing applications, you seem to think those are there to give you a better product.

Here is question for you, how many hours did it take for you to get your Penske and the USD's dialed in?

I believe the more adjustability a product offers, the wider the application the product can fit.
**It is a tactical error for Ricor to make a $900 shock for our FJ's with no provisions for height adjustment**
Period.

That is your opinion and that is all that it is. Yes, with all of the adjust-ability you can bolt the shock to a bunch of different bikes and it will work. As far as I know you have never ridden an FJ with a RPM shock, early or late design or fork valves, maybe I am wrong. But, I have no doubt based on the directions of this topic each & every time, your preconceptions would never offer any of the RPM suspension components a fair assessment.
   

Like I said, IAT valving technology is cool, but the writing is on the wall, it will be superseded by the ESA shocks with push button adjustability (there's that word again: adjustability) when they become available for our bikes.
Want to bet that those ESA shocks will also be height adjustable?
There's that word again.....

You have got to be kidding again right, who is their right mind would invest the cubic dollars into the application of a ESA (Electronic Suspension Adjustment) shock on a FJ? Hell, where would you place the stepper motor, and then you have to have an ECU and key pad; you had to modify your side panel to make your current shock work now...


I am sure you nor anyone else for that matter is aware, but once I sell this final batch of the RPM shocks I have received this past month I am finally able to completely recoup the investment I had to make to design & produce the RPM shock; It has taken three years to do that. Ricor told me I was crazy investing into a 30 year old motorcycle when I first talked with them, but they gave me a price, I evaluated and determined I could make it a go; and I did. Hell, Hindle said the same thing when I started the header system a few years back for the FJ and I am still working on recouping that investment.

Pat, I question for you: Do you know why the raising of the rear ride height makes the bike handle "better"? There are two main reasons why this affects the handling, do you know what they are?

Pat it is time for you to bring some tech to this topic and please leave the "expert advice" & the future out of it.

I received this email today from yambutt who is working with HyperPro for his rear shock needs.

Name: yambutt
Email: XXXXXXXXXXX@yahoo.com
Message: Randy, would've loved to get a used RPM shock but anyways have to go with hyperpro, so they need to know the length of the original rear shock on my 1992 fj, gonna stay with the factory length and raise it with the dog bones....thanks.

By the way Klaus Huenecke with hyperpro agreed with keeping the rear shock the length Yamaha intended it to be

With that, I guess we are in a dead tie on this topic...Ed and Donnie say longer shocks are the ticket and Randy & Klaus say, the factory designed geometry should be maintained...

I will close my post out with a statement I have both heard personally and has been written on the forum by our own Mark O who is a Penske shock and RaceTech fork valve owner. I know he posted it a while back, but it still hold true as demonstrated at the 2015 Renegade rally where the stock wheeled, RPM outfitted FJ lead the pack and there was only one who could keep up and he was riding an aprillia.

Alright boys, here is the dealio .

I had the opportunity to follow Mike Ramos at the WCR on the hwy 20 rip and grip . He was able to hang with the Nor cal Renegades . Known at the Wcr as the "fast five".

I purposely followed Mike R. so I could see his bike in action with the RPM front and rear set up in action. It performed flawlessly , no unsettled wiggle or big ass bouncy wiggyness . We were flying and even with the last second quick downshifts to 2nd gear and throttle up reducing corner surprises the suspension took it.

So, to sum it up the RPM stuff works as advertised.

I believe adjustable dog bones would be better than an adjustable length shock. The raising of the rear is necessary just to bring back to stock when you put a low profile 17" wheel on the rear. Those of you who want a better turn in ratio can raise it a little more for your liking.

Monkey Mark has a plan to use the shock linkage from a 89-90 on the earlier 84-87 fj's and says it matches so you can use the later model shock.

I have the race-tech springs and emulators on the front and the penske 3-way adjustable rear on My 86 . I have spent a bazillion hours and thousands of miles getting my fj just the way I like it.

With RPM Randy offering a one size fits all Rear shock I am thrilled . I will be doing a straight up comparison to how it works right out of the box as opposed to literally years of dicking around with the penske. Look for the Muppet Labs report when I am finished.

MarkO    

Randy - RPM

BTW, I got your pistons cut this afternoon, everything is assembled for the final pour in the morning. If all good, final assembly tomorrow.

[simi_ed]

Yea, it's coming...  Like a fine whine, no pix before their time ...

[ribbert]

BTW, I got your pistons cut this afternoon.......

Subtle! 

Noel

[Pat Conlon]

oooooh, I wake up and what do i find...

I concede: meaning I will accept as true many other FJ owners anecdotal evidence on the performance of the RPM shock.

I love quizzes: By increasing the height of the rear end you change the handling of the bike by reducing the rake of the front forks and by increasing the angle of the swing arm, you slightly shorten the wheelbase.

So what I've learned is this:
1) The RPM IAT shock made by Ricor is custom tuned for our FJ's and the tune is so fine that a 3/4" adjustment on the shock shaft will negatively affect the tune.
2) If the owner wants to change the geometry of the linkage by installing shorter dog bones, the IAT shock will be fine with the change.
3) If you don't have a suspension with dog bones, there will be no future provisions for length adjustment in the RPM shock.
4) Manufacturers, vendors and suspension folks who make, sell and tune height adjustable shocks advise that (slightly) lengthening the shock is advisable vs changing the swingarm linkage.

This is different than saying: There is no reason or benefit in raising the back end on our FJ's.

Heh heh, where else, but on our FJ forum can you lather up the best FJ vendor in the world while he is right smack dab in the middle of building your engine?

At this point in time is this really a good idea?

I thought about it before I replied, but what the hell, Randy is also a friend. I seem to recall that I introduced Randy to Don Richardson of Ricor. Don is the guy that came up with the tuned damper used in the Vibranators.

Discussion is good. Different view points are good. It's all good.

[giantkiller]

So I enjoy the quicker steering. From raising the rear of the bike. (And slightly lowering the front) Monkey Mark when are you going to make the upper shock bracket. So the early owners can adjust the rear ride height via dog bones and use the RPM shock. Randy someday I will put your exhaust on the 1350. Awesome exhaust. Unbelievably light. Are those pistons. Cut for the better oil rings for the 1350? Or is it something else?

[Pat Conlon]

I decided to change direction. Those are the 83mm long skirt Ross pistons. Randy's cutting them down to get the compression down to ~10:1

The report I had on new oil ring design for the Hank Scott Pro Lite pistons was that it did reduce oil consumption, but was still using oil, 1 quart every 3k miles.

[giantkiller]

Ross won't make them with lower compression? I thought they would make pistons to your spec's. And why are you going to long skirts?