Playing with forks again

V

Vince

Hero member
I am trying another round of fork mods rather than sending them to Maxton's. I noticed they were pulsing a small amount when cruising and if I held the brake and bounced it the fork would go down at a steady pace but rebound very quickly and then bounce down and back. Looked to me like it lacked rebound control. With emulators fitted the only adjustment for the rebound is oil weight, it had 15wt the recommended by Race Tech and set at 140mm forks bottomed and emulators and springs out. I had some 15wt and 20 wt so I made a mix of these 50 x 50 to get 17.5wt and as I was losing 20mm of travel at the bottom it's now set at 190mm. It's easy to do a volume calc if needed to find what cc,s would equal upping the oil level in 10mm steps if needed to stop bottoming. The emulators are set as soft as I could get them and they stayed at that setting. Bouncing them now has the compression and rebound speeds very similar and at a steady pace. I like its feel, now all I need is for the new mega sexy shocks to turn up. I have found 2 perfect bumps to do some testing to set these new shocks up on. The first is to a local street with massive speed bumps to set the low-speed compression and rebound on and the second is on those 20mm thick steel road plates with a nice square-edged bump they use to cover road excavations with, to set the high-speed compression damping. That's going to be really good fun sorting that out.
 
I would first set the rear shocks and then go on the fork again. much of the bouncing or feel of bouncing comes from the rear... set it as soft as possible without it swinging or bottoming out and then go for the fork. Always worked best for me... (and may I say, even Piet liked the suspension setup of my Jota, which is almost like getting the tip on your shoulder by the Queen with a sword... Almost, so don't call me "Sir Lothar", please, I don't deserve it - as of yet, at least... :sneaky:
 
Found this the other day, it's a bit too complicated to do with grease on my bike with its fork brace over the big external dust guard and the circlip on top of the green SBK dust seal so I am going to ease the big rubber outer cover out a bit and add a tiny squirt of Penrite magic oil in a spray can to see if it frees up some movement. This tip is posted a lot on the web, never seen it before yesterday.
 
I would not remove it, but make sure the whole setup is "relaxed". I have a fork-brace on my fork, too, since 25 years. the fork operates very good and sensible.
 
Ditto, Lothar, I have 135mm of more compliant fork travel and hopefully, on the road where I pinched my Sciatic nerve on a pothole a couple of months back, we're doing it again tomorrow, it will be nice and compliant, the fork and back hopefully. I learned years ago that bending and twisting resulted in a couple of weeks of pain. Its happened lots of times in my working life. I was twisting to my left to eyeball the idiot who suddenly panic braked just as I was closing to pass him and hit that unseen pothole. BTW standard Laverda suspension might be fine for the usual 70 to 80kg weight riders, but my 125kgs required changes. Even top-rate modern bikes require that to happen if they are set up for the best performance. Still waiting for the new shocks to arrive.
 
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Vince, I weight even more than you and got it set up nicely so that even for a much lighter rider like Piet, the setup was still good and comfortable. You will need a bit of pre-load on the springs (spacers) to get the bike to that level of "30% of total travel when you are on the bike". I don't even have emulators in my forks, just different (progressive) springs from - I think - Wirth or WP with some spacers at the top, set the oil-Level to the right level and mixed some fork oil to suite the rebound damping. All set up nicely and relaxed, including the fork brace (which even a not-to-be-named Laverda specialist could not get working). Relaxing the fork and freeing up any kind of resistance is one of the big secrets of a good working fork. second is the right setting. It's not overly complicate, you just need to follow some general rules strictly. I allways start with a cold bike test, pushing down the fork and the rear separately to see if there is any resistance. this needs to be fixed first.

Rest please use guides from the web that describe it best and much better than I could do it. There is no magic involved, it is purely testing and changing the setup accordingly. Most of the setup is try-and-error.
 
I checked the sag this afternoon when doing tyre pressures for tomorrow's ride. Full travel 135mm and sag with me on the bike 40mm. It will be interesting to see how it goes tomorrow.
 
Yes, it will. The fork worked well on the big stuff but I was still feeling lots of sharp small hits. That road is pretty bad, one section right on a fast sweeping bend had 80% of the bitumen missing and the hole looked really deep. I lucked out being close to the centreline of the road where the last 300mm of bitumen was still there in my lane. It was hard to tell if it was coming from the front or rear. It doesn't affect the handing much, the bike holds a line well, it's just pretty uncomfortable on rough bits. I used to get at least 3 or 4 massive crunches on roads like this in the past, but now it's small banging but there is a lot of that. For the 10,000 time, I had a play with the 4-position clickers on the Icons and as usual, after getting through 90% of the ride on the lighter settings I found No3 the best at absorbing the hits. It will be interesting to see what effect Megabuck shocks have on this.
 
Pretty sure it's the Koni/Ikon shocks mainly, unless you have 10 or higher grade oil in the forks. the Ikon/Koni setup is fairly tough. this improves handling (as it raises the riding hights on the rear compared to the rather soft AG Strada) but also gives a lot of "feedback" from the road back to the rider.

Just in addition: which rims (original or GSX-R?) are you having and which tires, please? What is the tire-pressure front and rear?
 
Boranis, std front and 3.00 rear. Bridgestone T32. Front 37psi and rear 40psi. I tried less air in the front but didn't like the loose steering.
 
sounds about right to me. I typically have 2,4 +/- 0,1 bar on the front and 2,7 on the rear, wich is close to your setting (GSX-R-Rims with BT012SS). So - I would recommend really to wait for the new shocks before you change more on the front. Stearing head nuts are set to almost to loose?
 
My new shocks have turned up and they have their spring rate on the build sheet but it's Imperial with no distance included. All it says is 125/150 LBS. I am used to N/mm. Does anyone have a conversion for this into metric?
 
I would have but half the rating isn't included, I hate guessing
I am guessing it's lbs/inch as that's in the following chart and found this conversion page.

.: Spring Rate Conversion Calculator :.

Enter the value you want to convert Conversion results After you have entered in a value please select a conversion. Convert lbs/inch kg/mm Convert lbs/inch N/mm Convert kg/mm lbs/inch Convert kg/mm N/mm Convert N/mm lbs/inch Convert N/mm kg/mm Convert inches mm Convert mm inches
norwestsuspension.com norwestsuspension.com
 
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