Let the fun begin...RPM Rear Shock

[1tinindian]

I am open to opinion.

Raising rear = Improved turn-in.  to the point that it can become unstable, so you don't want to go nuts.  You can also drop the front.

Frank

That was very noticeable when I raised mine.
That and the RPM fork valves were the two biggest improvements that I could have done to make the FJ a lot lighter on her feet.

Leon

[racerrad8]

True but if you raise the back, this improves ground clearance and will allow you to lean the bike over farther in a turn.

It also raises the center of gravity making the bike less stable. The FJ is so solid this would take a huge change to make it unstable. JMO
Kurt

But if the shock/spring do the proper job of maintaining the ride height while in compression in the corner and not let it completely compress the spring/shock, would there be a need to raise the bike?

Randy - RPM

[Persistant]

"Well, a lot of people got to hold one at the WCR, someone even had a chance to ride my bike with one installed but unfortunately it sat all weekend."

Hey Randy thanks for the update, I figured it would have been a topic of discussion at the WCR.  Although my choice (ok, more life circumstances) that I did not attend the WCR I sure would have loved to and felt a little left out of the loop.....sniff sniff....

Cheers,

Andrew

[racerrad8]

Although my choice (ok, more life circumstances) that I did not attend the WCR I sure would have loved to and felt a little left out of the loop.....sniff sniff....

Cheers,
Andrew

Andrew and everyone else for that matter, start planning now for 2014 and saving your nickels and dimes now...I think it is going to be fun.

30 year anniversary of the birth of the FJ and hopefully a proper way to celebrate the Legendary status of the FJ.

Randy - RPM

[yamaha fj rider]

Randy just a small change in steering heat angle will make a big change in the handling. Raising the back end will do this. As to your question about a proper shock set up and spring. The goal is to bring all the pieces together to make the bike handle as well it can. Yamaha may have not setup our bikes to handle as well as they can. The shock you are working on is an example of this. Set up from the factory, they need to fit a large spectrum of riders. So there is room for improvement. This one of the things I have been waiting to see. What will need to be done to tune the shock for my bike and riding style.

Your fork valves are a huge improvement. I was running progressive springs and synthetic fork oil which made the front much better than stock. When I installed your fork valves and new springs. I would say this was double the improvement of the first change. Very impressive and if you were stock before WOW.

Kurt    

[Flynt]

I think you'll need to read up on steering angles (rake, trail, etc) to see what you're causing to happen dynamically when you raise the back.  The clearance point is a good one as well and I have never dragged a peg on the FJ (or any other bits).  

I don't know exactly why raising the back and/or lowering the front works, but my intuition on physics would say that raising the rear and/or lowering the front decreases rake angle and puts more of the weight of the bike through the forks...  less on the forks from the side = easier pivoting of the forks and less tendency to self center.  This combination makes for light, quick steering.  

If you get to the point where the self centering is too weak to hold the bike up, it will tip into corners and you'll need to counter steer to keep it upright...  that means you've gone too far.  Up to that point I think you're in a "season to taste" situation.  Lowering my front end 1/2" made a huge difference in turn in and cornering stability.

Frank

[yamaha fj rider]

In my experience if you take to much rake out of the bike it will make the bike head shake. Head shake is when the bars pivot from side to side uncontrollably at speed. This is why you see steering dampers on bikes.

Kurt 

[The General]

Although my choice (ok, more life circumstances) that I did not attend the WCR I sure would have loved to and felt a little left out of the loop.....sniff sniff....

Cheers,
Andrew

Andrew and everyone else for that matter, start planning now for 2014 and saving your nickels and dimes now...I think it is going to be fun.

30 year anniversary of the birth of the FJ and hopefully a proper way to celebrate the Legendary status of the FJ.

Randy - RPM

+ 1..Same for the Snowy Ride - It indeed will be Epic, Legendary and Global. ...Oh, also the spot on long range forcast providers for the Aussie Bellingen Rally, already have early March 2014, as absolutely perfect riding conditions... Hoping to get attendees from NZ and Europe as well as those saving their U.S. Dollars. (Some are including Phillip Island WSB +) 

[oldktmdude]

+ 1..Same for the Snowy Ride - It indeed will be Epic, Legendary and Global. ...Oh, also the spot on long range forcast providers for the Aussie Bellingen Rally, already have early March 2014, as absolutely perfect riding conditions... Hoping to get attendees from NZ and Europe as well as those saving their U.S. Dollars. (Some are including Phillip Island WSB +) 

The way the Aussie dollar is falling at the moment, our overseas Rally attendee's will almost have a free holiday.   

[Mike Ramos]

Hello everyone,

I would like to chime in with my impressions of the rear shock from R.P.M.  This will be as it pertains to my 1991 FJ.  As mentioned in a previous post, I had the opportunity to purchase a pre-production unit from the gentleman from RPM.  I currently have over 10,000 miles on the shock over a wide variety of road conditions. 

Re: the comment that "Yamaha may not have had it right - thus the shock from R.P.M." and other discussions about the proper linkage ratios... well yes & no. 

After I installed the Fork Valves (and brace) I blew out the stock rear shock so I modified and installed a late model shock from a Yamaha sport bike.  It is the same shock which I rode with for the Colorado Rally and it performed well (having 3 rebound & compression damping adjustments). 

However it did change ride height which I compensated for by adjusting the dog bone length, thus changing the linkage ratios which at the time I had reservations doing but with no other option.

Enter the shock from R.P.M. -  It must be understood that the shock operates on a different principle (that I do not claim to understand) all the while the full travel of the shock is indeed utilized.  Just as is the full fork travel utilized with the Fork Valves (review the video from the Colorado Rally and you will see the fork operate throughout its' full range) but never is there bottoming - a question I was specifically asked at the time.

Re: sport riding...  As far as when entering a turn under hard braking and then releasing the brakes at a desired point during the turn, these suspension components all but eliminate the chassis 'upset' or spring back that is encountered while cornering and which has been discussed previously.  While my riding ability may be limited, my experience with this phenomena is very real. 

Returning to linkage geometry, ride height & sag etc. - I have long had adjustable dog bones and have experimented with a variety of adjustments.  I do not believe there is benefit in raising the ride height (lowering the rear wheel) - sure the bike will turn in a bit quicker but AS IT PERTAINS TO STREET USE so will putting on a tire with a different profile.  And I have yet to find a road which would have been traversed quicker with the increase in rake.  And as someone else noted it may decrease high speed stability.

I also believe that Yamaha came pretty close to all an all around compromise with regard to the linkage geometry and having changed it to accommodate a very competent shock, using the new shock from RPM allows the linkage to return to normal lengths and thus ratios. Having changed the ratios to accommodate the modified Yamaha shock, I would just as soon return this aspect of the suspension to stock (and I have).

Now, as far as increased ground clearance:  The peg ends and the chin cowl are indeed scrapped up HOWEVER since installing the suspension components I not scraped anything with the recommended spring rates and sag settings provided by Randy.  The settings may not be 'traditional' and admittedly it seems counterintuitive to get improved sport performance from softer spring settings, but the evidence is empirical.  I believe it was mr. happy himself DavidR who first mentioned the excellent ride quality of the rear shock from RPM as it compared to his Penske.  While I have never had a Penske shock I had one comparable to it.

As with other items I have purchased from RPM, and only after many miles under a wide variety of weather & road conditions, I can without reservation recommend the rear shock from RPM.

Ride safe,

Mike Ramos. 

[ribbert]

I do not believe there is benefit in raising the ride height (lowering the rear wheel) - sure the bike will turn in a bit quicker but AS IT PERTAINS TO STREET USE so will putting on a tire with a different profile.  And I have yet to find a road which would have been traversed quicker with the increase in rake.  And as someone else noted it may decrease high speed stability.

Now, as far as increased ground clearance:  The peg ends and the chin cowl are indeed scrapped up HOWEVER since installing the suspension components I not scraped anything with the recommended spring rates and sag settings provided by Randy. 


Ride safe,

Mike Ramos. 

I have raised the rear, but not as much as most (about an inch off the ground) dropped the front a little and it made a noticeable difference. Then I started using a front tyre that has a rounded profile similar to a racing tyre and it was better again.
The aim is not to be quicker from A to B but doing it easier, not having to wrestle the bike into turns. I get to ride a number of new bikes and the FJ still feels surprisingly nimble when cornering hard.
There is certainly no loss of high speed stability, even with luggage. I imagine there would be if you over did it though.
I have a standard bike of the same model also, a quick ride on that confirms the improvement these changes make.

I'm not sure how you attribute no longer scraping things to the shock. In my case I am expecting the opposite by having a shock I can run softer. I have my rear set uncomfortably hard to stop wallowing and I doubt it compresses much in corners and it's a long way over to the chin fairing bolts.

Noel

[hein]

Its not the rake of the front end that gives stability its the positive trail. By raising the backend of the bike you obviously reduce the effective rake but the key result is reduced trail which makes the steering both lighter and quicker.There are a multitude ways of changing trail. To decrease trail you can raise the backend or lower the forks through the triple trees both will decrease the rake and more importantly decrease the trail.Both will change the ride height. A more radical approach would be to cut the neck off and weld back with reduced rake and trail which would not effect ride height. A more common method not requiring this kind of metal surgery is to increase the offset of the triple trees. By increasing the offset between the steering stem and the fork tubes you maintain the same rake but reduce the trail.

Raising the back or lowering the front is obviously the easiest and cheapest solution. An adjutable lenght shock allows you to change the ride height and thus change the trail. It does not affect  spring sag or preload nor will it affect damping.

Changing the links will also do this but an adjustable lenght shock will allow for more tuning without making up an assortment of links to play with.


Hein.

[fintip]

 

[Mike Ramos]

Good evening,

"I'm not sure how you attribute no longer scraping things to the shock. In my case I am expecting the opposite by having a shock I can run softer. I have my rear set uncomfortably hard to stop wallowing and I doubt it compresses much in corners and it's a long way over to the chin fairing bolts."  a quote from Noel

As I stated in the previous post it is counter intuitive.  With the RPM suspension components softer springs are used, however the problems such as wallowing are compensated for (as I understand it) through the valves.  And that is the impressive aspect, a soft ride when not under sporting conditions such as cross country riding but the very same shock settings do very well under actual sporting rides.

I am not easily swayed by individual claims as to a particular product's performance (e.g. the oil pressure & temperature gauges to verify the performance of the oil cooler from R.P.M.). There is a whole lot video & notes of various suspension settings that do indeed verify the veracity of the suspension components.  Empirical experience is not easily compromised.

Recently I posted a copy of an e-mail  sent to Randy following a high speed encounter with an automobile over a very rough & unforgiving surface.  Previously, I have on a video [which I have shown to Randy] a high speed entry into a Bay Area tunnel where the surface undulated rapidly, the full length of travel on both the forks & shock were in play.  My reservation in that instance was that the motorcycle would become airborne and throw me into the wall of the tunnel. Fortunately the wheels never left the ground.

In the first instance with the automobile I was traveling light without luggage.  The second was at the beginning of a cross country with moderately loaded luggage, a full tank of fuel and about two gallons in the auxiliary fuel tank.  The point is that the road conditions and loading are diametrically opposite.  Not to mention the recent WCR where I arrived with full luggage but went on the daily ride sans the luggage.  HOWEVER the suspension setting were exactly the same in all of these situations and the suspension components performed flawlessly. 

Such has been my experience over a considerable length of time and a lot of miles.  There is not a lot more to say...!

Ride safe,

Mike Ramos.

[X-Ray]

Not to mention the recent WCR where I arrived with full luggage but went on the daily ride sans the luggage.  HOWEVER the suspension setting were exactly the same in all of these situations and the suspension components performed flawlessly. 

This statement to me sums up exactly how a quality rear suspension system would ideally work, and sounds like it does. That being the case, it will be the perfect upgrade to most, if not all rear ends of our beloved FJs'.