RPM Fork Valves

[SlowOldGuy]

BOTH are static sag. One is BIKE sag the other is RIDER sag.

This is still a confusing issue I have.  My 0.95 springs give me the correct rider and bike sag.  If I go to a softer spring and adjust for rider sag then the bike sag will be wrong (probably too small since the softer spring will require lots of preload to achieve required rider sag).

DavidR.

[axiom-r]

Agreed Randy- sorry to have complicated the discussion. It is confusing though!  DavidR hit it- it is all "static sag".  I get my info and instruction from some buddies that are competitive racers and they helped me to dial in my suspension.   I think their range is more closely suited to sport or track conditions and I was hoping to hear what sag range might be better suited for sport touring or just touring....  DavidR, the way these guys do it is they set the preload to where the bike is squatting about a quarter inch all by itself under its own weight then adjust further to set sag with the rider on.   The more critical issue is Rider Sag so if need be just focus on setting your preload for that.  When you have it close do some compressions standing next to the bike- if it "bumps" (hits the top) when you do a quick release from compression you have too much preload..

My bike currently sags the .25 inch and then drops another .5 when I get on... thus the .75 just a bit less than what you were indicating Randy so I think that translates to a firmer suspension with a bit more preload.  I may try baking off preload a bit and letting the sag increase to the range you are indicating and see where it gets me...

cheers-

Tim

[Mark Olson]

1.what is the recommended static sag ?
2.what is the recommended rider sag?
3.what is the recommended oil level with forks compressed and the valves and springs out from the top of fork, down to the oil?  130mm?
4.what is the proper placement of the washers for the fork springs ? is one needed on top of the fork valve? or just the spacer ends?

I understand the fork valves are pre adjusted and go in only one way with the long part up, but is there an adjustment necessary for a more spirited rider?  more oil? or 1 turn of the adjuster nut?

As it stands the noise from the front end sounds like a old whores bed springs.
does everything just need time to settle in?

I may have overdone the preload.  

Mark O.

1) The "static sag" is as recommended in the spring installation instructions: 25-30mm
2) What is rider sag?
3) As listed in the RPM fork valve installation instructions: 6" or 152mm*
4) Washers are only required at each end of the spacer. If you have the stock washer at the top, the additional spacer included with the spring is not required.

The spring pre-load should be 15-20mm (as specified in the spring installation instructions)

I have heard that as well, but after they settle the noise is less, but there is still some noise. It comes from the spring actually being compressed and rubbing against the inner wall of the fork tube and the thin oil. That was something you could not do with the other valves...

*The oil level can and will continue be a tuning tool. There is not an adjust of the valve without complete disassembly. The nut on the top is holding it all together it is not a tuning adjustment. If you feel you need to tune the valve, I will have the tool and shims available after I get the next order so you can play with the shim stack.

Randy - RPM

thanks for the replies.

1. bike only drop
2. rider and gear
3.there where no instructions with the valves ,they were just shipped in the race tech spring box according to Craig , maybe he lost them?
so I have way too much oil ?  where is this measurement taken from?
4.so the spring sits directly on the RPM valve?

just trying to be clear ,I was working with no instructions and just copied what I remembered when I installed race-tech on my fj.

Mark O.

[racerrad8]

thanks for the replies.

1. bike only drop
2. rider and gear
3.there where no instructions with the valves ,they were just shipped in the race tech spring box according to Craig , maybe he lost them?
so I have way too much oil ?  where is this measurement taken from?
4.so the spring sits directly on the RPM valve?

just trying to be clear ,I was working with no instructions and just copied what I remembered when I installed race-tech on my fj.

Mark O.

Yep after we talked, my shipping department must have omitted the instructions, sorry to create the confusion.

I am grooming him to help, but the little things seem to be the hardest...

I emailed them to both of you and hopefully the process will finish much smoother.

Randy - RPM

[soundmindryan]

Randy,
I know that you've done CONSIDERABLE testing to get the right valves for the FJ, but I KNOW you've been asked or have yourself considered applying these to other bikes: dirt bikes, in this instance. I was describing your valves to a friend who runs an '81 YZ250 in a vintage class and we were WONDERING  if they can be adapted. I believe that bike runs 43 mm forks but just askin...
Thanks and I'll take my answer off the air...
Ryan

[Mark Olson]

Fork valve update,

Removed the extra washer and adjusted the oil level to 6" and adjusted the pre-load on the spacers, set the d-rod adj to medium as per instructions .

current sag with rider is 27mm.

too much pre-load and too much oil before.

feels much better , gonna run it for a while and check out the numbers after it all settles in.

[mickarch]

Hi Folks,

Having ordered up the fork valves and springs shortly after they hit the market and installing them as soon as they arrived (which was like 3 days after I ordered them, thanks to Randy's quick turnaround with shipping), the weather and work decided to conspire against me getting some quality seat time to test them out.  That was until this weekend.  So now that I've got some miles on the them, I thought I would offer my impressions.  Note that I am in no way skilled at suspension work or tuning, I generally follow instructions and hope for the best when it comes to these sorts of things.

For starters, as noted the parts arrived very quickly and for the most part in excellent shape.  The only thing I noted on the one of the valves is that the allen head on the bolt was a little wallowed out, which didn't look like would affect anything, so into the forks they went.  Installation was easy, the forks weren't leaking so I left them on the bike, just drained them, pumped them up and down a couple times the get as much of the old fluid out, added the new oil, dropped in the valves, springs, spacers and washers and sealed them back up (I've got a '93, so no 'D' rod mod).  My only concern with the install was that the valves slid freely down the oil and only required very light pressure with the spring to get them through the oil and seated.  For some reason, I assumed they would be a tighter fit but a quick email to Randy eased my mind.

I should note that the majority of my riding is touring in nature and predominantly in a straight line, not a lot of curves or fun roads in SE Michigan.  I'm mostly concerned with comfort over our rough roads.  I put about a 150 miles on them today on all manner of roads and have to say overall they are quite an improvement over my old springs.  I'm not sure what the old springs were, they were progressive but not stock as they had +/- 4" long pvc pipe spacers installed to get preload, no markings on them.  Anyways, my experience so far is that the forks seem much more compliant over large cracks / potholes and sharp bumps.  The ride is super smooth on the expressway, they seem to work better the faster I am traveling.  I don't even notice going over big cracks or wide expansion joints on overpasses.  I played around a bit with the preload by using the adjusters in the caps and settled with the adjuster at 1 notch in from all the way out.  If I went in 2 notches, the ride became noticeably harsh on the highway.  I haven't measure sag yet, so I'm sure where that's at.  I noted that the forks performed better the sharper the profile of the bump was.  I'm assuming that has to do with the inertia valve opening and allowing fluid to bypass the shims.

The only issue the new setup didn't resolve are the large "humps" in a lot of the roads around here.  They're not sharp bumps, but rather tall and wide humps that the bike rides up, over, and back down rather than absorbing, mostly on surface streets with speeds around 40MPH.  I'm not sure if anything would be able to absorb them given their profile.  I wonder if a lighter spring rate, or less oil to allow more compression of the shock would help with these humps, though I'd hate to go too soft and run the risk of bottoming out.

Overall I give the new fork valve / straight rate spring kit two big thumbs up    I'd like to thank Randy for putting in the effort to develop these, and to all the group members that had a hand in their testing and refinement.

Thanks Fellas!
mickey

[racerrad8]

Randy,
I know that you've done CONSIDERABLE testing to get the right valves for the FJ, but I KNOW you've been asked or have yourself considered applying these to other bikes: dirt bikes, in this instance. I was describing your valves to a friend who runs an '81 YZ250 in a vintage class and we were WONDERING  if they can be adapted. I believe that bike runs 43 mm forks but just askin...
Thanks and I'll take my answer off the air...
Ryan

I have inquired but I have not heard back yet.

A couple of things I need to know;

Bike weight
Current spring rate
I.D. of the fork tube

The wall thickness of the FJ tubes required a set to be specifically made for the FJ, but they do offer many other street & Dual sport valves that might be able to drop right in.

Randy - RPM

[racerrad8]

Thanks Mickey,

I am glad you are happy with the valves. You can definitely play with the oil level to see of you can get the undulations under control. I do not recall what spring you ordered, but the better the fork can move, the better the valve works. If you are close to a break point of the spring rate, then go with the lighter spring,

I can honestly say that I do not even look at the valves before I send them out as they are sealed in the bag from the manufacture. The hex use used during the building of the unit and does not affect the operation.

I will check my others and let the manufacture know if the issue as well.

Thanks again,
              Randy - RPM

[mickarch]

I ordered the 0.90kg springs and am at the bottom end of the weight spectrum for them all geared up.  I went with the 0.90 because I tend to take long trips with a fair amount gear on the back of the bike weighing it down.  Didn't have any luggage on for the test ride though.  Maybe I need to get the softer springs for day trips and keep the 0.90's for the longer trips.  Only takes a few minute takes to swap them...worth considering.