Let the fun begin...RPM Rear Shock

[p51bombay]

p51 Bombay,

If you review Randy's post explaining how the Fork Valves & rear shock were developed SPECIFIALLY for the FJ then any "logic" that you are using to justify your statements comparing a H-D to the FJ's is sheer, well just say it is comparing apples to oranges.

I did read it, my point was not to compare a HD to an FJ because you really can't- in fact I just sold this one yesterday and will be replacing it (so to speak) as my main street bike with another FJ1200, most likely a 90 model that I am looking at Monday.  Why?.........because despite the fact that I spent nearly three years making it what I thought it should look and perform like, over this last winter it occurred to me that I had done about all I could in making it into a cafe styled bike, if an admittedly heavy one.  While the look is right where I wanted it, the fact remains that in spite of suspension changes to improve things, it has very limited ground clearance on even the most mundane corner and I could never get my feet into a rearset position due to the placement of the rather large primary.  What WAS my point then?...........only that before I even knew the RPM valve was essentially a reworked Ricor unit, I had prior experience with the concept and can verify that they do actually work.  FYI - I don't get into the one bike is better than the other bike, aka: Harley's suck, or are better than everything else depending on which side of the barn you stand on - a HD is a well built machine well suited to its purpose as is an FJ and many other bikes.  I sold mine because it didn't suit the kind of riding I like to do, simple as that.

[BSI]

p51 Bombay

forgive us if we are a little loyal to Randy, you obviously have no clue to how much he has contributed to helping us all enjoy our FJs more than we ever envisioned....his total FJ knowledge that he shares, his superior developed FJ parts and a sincere desire to provide help is very valuable to all us, including you.. which he immediately did this Sat afternoon when I emailed him a question and got an immediate answer...good luck on getting another manf/distributor to do that

Best regards,
Louie

[Mark Olson]

hey Mikey , he likes it.

[brentjgordon]

REALLY I WANTED TO BUY ONE  BUT YA KNOW ....they are not free but, the tutorial you posted on this site and all the little goodies you sell at rpm seem almost free, i built my own carbs using your info and when i mounted em up (fought like a pro wrestler on crack till i pulled out the heat gun the it happened in less than ten seconds they just popped right on andi had to sneak to the river to go fishin cause i told my girl it would take all night!) the carbs already had a dynojet kit in em and with your fastner kit and oring kit and just one needle and seat and YOUR DETAILED INSTRUCTIONS my bike runs sweet, even starts easy cold. the best part is i understand whats goin on~thank you very much for your help, if you ever know anyone needing spare carb bodies the fj1100nc carbs a couple were unusable but i found some fj1100n and tossed the canisters in a drawer with the two spare carb bodies rails and assorted hardware find some body needy they can have what they need for shipping, stuffs not new but then it really dosnt need to be! rebuilt my clutch master and slave so once i paint im riding this old girl down the road mainly because of you and fjowners.com~ you guys are great...

[Persistant]

I can only guess Randy's frustration in getting the RPM shock out to those who wait with baited breath....my question is:  Was there any talk at the WCR regarding progress in getting it out to the public?


Cheers,

Andrew

[racerrad8]

....my question is:  Was there any talk at the WCR regarding progress in getting it out to the public?

Andrew

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.

I have spoken to the manufacture and as of yesterday they are re-manufacturing the bottom end of the shock as they forgot about my email telling them of the interference issue I was having. After I forwarded the original email it was soon recalled...

The shocks were here, at RPM and much to my frustration they all arrived wrong and had to be sent back

They got them back on Tuesday and hoped to be able to change out all of the lower ends and get them ready to send back by Friday. I will be calling in the morning again to see if they were successful.

I also told them yesterday after the feedback at the WCR that they should start on the second batch as well, because I think the first one will sell pretty quickly.

Believe me this is on the front burner and I am working on it daily, pushing firmly to get these things done. I have already spent a ton of money on springs, shock covers, & tools which are sitting here everyday costing me money as they cannot be used on anything...

When and if I get any further news I will pass it along, but until I know something I really do not want to keep repeating myself with the same bad news...

Randy - RPM

And while I'm at it no new news on the exhaust either...

[FJmonkey]

Randy, I was very happy to hear that the 84/87 shock that you are releasing will be upgradeable to the length adjustable shock for the second generation. This makes it easy for me to decide to make a grab at your first shock and upgrade when it becomes available. Tell me I am not dreaming.....

[racerrad8]

Randy, I was very happy to hear that the 84/87 shock that you are releasing will be upgradeable to the length adjustable shock for the second generation. This makes it easy for me to decide to make a grab at your first shock and upgrade when it becomes available. Tell me I am not dreaming.....

That is the plan, I am going to try and get them to build an adjustable end for both version to offer height adjustment.

The biggest issue for them is the changing to the swingarm linkage angles and how that can affect the shock and spring rates.

For instance, I notice on the BMW shock that a few have done, the relay arm is almost at full extension and that has a drastic effect on the spring rate & shock valving compare to the stock position.

It is in the drawing board/thought phase and if I am able to make it work, then it will be something to come out down the road sometime in the future, but right now we are only talking about it.

Now, Mark I have to ask...

Why do you need to have adjustable length on the shock?

Randy - RPM

[FJmonkey]

Now, Mark I have to ask...

Why do you need to have adjustable length on the shock?

Randy - RPM

I am asking because ride height in the rear (geometry issues) seems to affect our enjoyment in the corners... I am not that fast in the corners so I am open to opinion.

[racerrad8]

I am asking because ride height in the rear (geometry issues) seems to affect our enjoyment in the corners

How and in what way?

Randy - RPM

[yamaha fj rider]

Ride height and sag is very important to proper set up. Especially for the early FJ's, no dog bones. Changing them + or - 10mm makes a huge difference. The shorter raises the back end of the bike and makes the spring feel stronger (stiffer). Shortened my bones 10mm, huge improvement in my bikes handling. Hope this helps.

Kurt     

[Flynt]

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

[racerrad8]

Ride height and sag is very important to proper set up.

The shorter raises the back end of the bike and makes the spring feel stronger (stiffer).
Kurt     

Thank Kurt, I agree that sag is very important, but not sure why the ride height needs to change. This is the debate the shock manufacture and I are currently having and I would like to understand more.

If the shock and spring are the proper set up for the bike and the correct sag is maintained when the rider is mounted, then how does changing the ride height affect the ride.

Is it just because it makes the spring feel stiffer?

If so, then the correct rate spring should be installed to compensate for the weak spring which increased the sag and lowered the ride height.

Here is where it get cloudy...

The early model bikes have the aluminum relay are & linkage that are non-adjustable. So, when I bolted my new shock on my bike for testing, I used the shock that is the same length as the stock shock to maintain swingarm linkage geometry. I installed the correct rate spring to control the sag, which in turn maintains the ride height and swing arm angles the bike was designed with.

The late model bikes can have the dog bone changed to affect the ride weight without affecting the swingarm linkage geometry. That shock is also the stock length, but a couple of riders had adjustable dog bones.

Now, are all of these changes done because of the poor rear shock/spring assy?

Now, if you have one of the other aftermarket shocks on the market that are a shim stack design they are set up pretty soft on the shim stack to maintain ride quality. Since the shim stack is so light, they have to put a heavy rate spring on it to control the swingarm movement, ride height & sag. So, they give you a weak shock and a stiff spring.

I would like to hear more as I need to be able to convey why changing the ride height does anything for the handling.

I understand things like it makes slight changes the steering head angle steeper, it shortens the wheel base slightly, but I need to understand why the raising of the rear of the bike effects the handling other than changing the relay arm angles and changing the effective spring rate.

The only concern from any of the test riders was the fact the he has a YZF wheel on his early model bike and the static height of the wheel is lower. He would have liked to raise the rear slightly and I understand that. He did have concern when installing the shock that the pegs would drag, but they did not.

That concern and only that concern will be the only reason the early model shock might end up being adjustable...Unless other reasons are made clear to me and I can present them to the manufacture as a reason for change.

The late model shock can maintain the stock swingarm geometry and the dog bones can the change the ride height so it does not need to be length adjustable.

Like I stated earlier, the BMW shock is much too long and severely alters the swing arm geometry to the point the center stand has to be removed. The acute angle of the linkages in the photo below demonstrate the maximum length of the shock and how it affects the ride height, spring rate and sag.


I am not knocking those who have it installed and are happy with the results, but as I person bringing a product to market, that alteration to the geometry is not acceptable.

The other thing that I need everyone to take into consideration, the new RPM shock will not compare with anything currently on the market. It is not a universal shock that is shimmed and sold with all kinds of adjustments to make your bike handle with a gigantic spring.

The RPM shock uses the same light spring technology the front of the bike uses to allow the patented bypass circuit to function and give you a superior ride. The final two test riders are current Penske owners and both of them are patiently waiting for the shock to be available as well, because you cannot compare one to the other.

The bike feels lighter, turns in quicker, brakes and accelerates better because the package has been designed for the FJ specifically. I think once they hit and everyone gets them dialed into their liking, the results will look just like the front fork reviews.

But with that said, I still need to be able to understand more clearly why raising the rear of the bike affects the handling and fully understand and be able to explain to the manufacture why it is needed because they are currently against it as it will effect the shock shim package and spring rate.

Randy - RPM

[yamaha fj rider]

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
[/quote]
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

[Thmsdoyle]

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

How much lower from stock can we lower the triple trees on the forks?