We all have the harshness in the R Ohlins forks, i am going to replace the few months old 5w oil to Motul 2.5w..i know the forks need re valving to solve the problem.. trying that lighter oil first in the comp shock... dump and run, not a hard job...maybe leave the 5w in the rebound shock, i can test the compression shock by hand if there is any change before and after... ....anyone else done this ....Will update later
Well, it is absolutely amazing what one 0.006" thick shim with a 16mm OD and a change in fluid can do to the ST1200RS' forks. I'm now in love.
Always check the oil level spring out...not dump and run...did last owner change the oil?....level was 130mm should be 90 mm...much better feel in the front not as harsh
Not sure I understand your post Glenn. Are you saying your forks were at 130mm (oil level), you changed it to 90mm and the front was less harsh? I set my oil level at 130mm per the manual.
Even after the cross over shim, I still felt the higher speed compression was a bit too harsh. The bike was much much better but I could not resist one more change. I reduced the first three 28mm shims from .15mm to .10mm. The low speed adjuster went from 21 out to 5 out and I'm even happier.
When i did the dump and run i just measured what came out and put it back spring was in....are we talking about the Shawa or ohlins forks ..ohlins just has preload...comp and rebound yours must be the Showa..ohlins has no adjustment on the lower shock ...i watched a u tube vid on the whole job and level was set to 90mm... ....the way it feels now on the hwy its not as harsh...still not perfect, but i dont have eyballs bouncing...i will post the vid... link to the youtube video 9.45 minutes in level 90mm
My understanding from the NIX30 cartridge manual is that the smaller the air gap, the greater the "spring rate" of the air spring is and thus the higher the overall spring rate of the fork. This is why I questioned things getting better. BTW, if you went far enough to remove the fork and change the oil you were nearly all the way to revalving. If you look at the manual, you'll see there is about another 15 minutes of effort
Well guys after another road test and adjustments front shocks were still harsh over the crap roads here in Cali .... So i decided to give the Motul 2.5 fork oil a try in both forks...wow big difference in the feel now harshness almost gone much better soaks up the bumps .....Pre 7....Comp 18...Reb 11... rider sag front 50mm some fine tuning on that later
I should have shot a video on the shim thing but it is straight out of the manual step by step. I just put one crossover shim in the stack in position three when I reassembled. Otherwise it was just doing a fork service as outlined by Triumph. I too did an oil change. The kinetic viscosity of the fluid I used was close to that which came out of the forks but the seal stiction is way way down. Absolutely love the bike now and it responds as good or better than my active Ohlins bikes.
Sounds good. Can you expand on this a bit please as in how do you identify the high and low speed sections and how do you decide how much to add or remove? Also are you saying you ADDED a 0.006" shim, or did you take one away? I think I want to do similar to my Kove 450 rally especially the low speed compression and bring it back into range from 21 of 22 clicks out, down to single figures as you've done. The forks on big hits and jumps works ideal, so I don't want to spoil that end of the range.
Well, it is absolutely amazing what one 0.006" thick shim with a 16mm OD and a change in fluid can do to the ST1200RS' forks. I'm now in love. and Even after the cross over shim, I still felt the higher speed compression was a bit too harsh. The bike was much much better but I could not resist one more change. I reduced the first three 28mm shims from .15mm to .10mm. The low speed adjuster went from 21 out to 5 out and I'm even happier. So the black art (read, experience) of fork valving consists of having tried stuff in the past and had it work along with a willingness to go at it several times to get to where you want to be. In this case, I spoke with a friend who is a long long time motocrosser and has spent countless hours messing with forks. His suggestion was to add what is referred to as a "cross over" sim to the stack. In practice, it means adding a small diameter shim behind the first number of large diameter shims at the bottom of the stack (near or up against the valve) to allow those initial shims to bend just a bit easier to crack open a bit when loaded. This adds a path for a bit of fluid flow under relatively low pressure which gives you more low speed bypass and softens just a little bit the lower speed response. As noted in my posts I quoted above, I tried this and it made a world of difference. Per the first post, I purchased a .006" thick 16mm OD shim and placed it between the third and forth shim in the stack (IIRC, I need to go back to my maintenance records and verify exact positioning). This lesser diameter shim allowed the outer edges of the first three shims to crack open with less pressure. This worked nicely but I wanted just a little softer low speed. For grins, I changed the first three 26mm OD shims from .15mm to .1mm. That was likely a tad too much but I've been too lazy to go back and change the first shim back to .15mm. I'm running at about 4-5 clicks out on the low speed compression with the three thinner first shims where going back to the thicker for the first shim would probably put me around 8-10 clicks out. Not a big deal which is why I've not bothered to change it. I'll get it the next time forks are off for fluid changing. It is best to find a shop and buy the single shims from them. Ohlins sells them in 25 pcs packages which is a bit much if you are not doing it a lot. I've dealt with .15mm and .10mm shims with ODs from 16mm to 28mm. You can reach out to your in country Ohlin's dealer and they will normally give you the build sheet for your OEM Ohlins product using the laser etched serial number on the inside surface the caliper hanger area on the fork foot. The build sheet has everything from the shim stack to the valve part number along with every other component in the build by part number. IIRC, the shim stack in my 1200RS front manual adjustable forks (FL9510) was something like 3 .15mmx26mm, 2 15x24, .15x22, .15x20, .15x18, .15x16,,,,. I stuck one .15mm x 16mm shim between the first three 26mm and second two 24mm shims in the stack as a first pass then made the first three 26mm shims thinner on the second pass. It all sounds so terribly complicated until you realize I stuck one $1 washer in the stack of washers on the first pass and swapped three $1 washers out on the second pass Hope this helps.
As far as how you identify what does what, look at that conical stack of washers and just think about how they bend up when fluid is pushed against them. You can play with numbers of washers, thickness of washers and diameters of washers to change how much fluid gets to sneak by at differing pressures. If you want to get crazy, you can even switch out the valve that the washers land on (size and number of holes in the valve) which affects the flow area facing the shims. I've never had the patience to do this and, judging by the build sheets for my Aprilia, Ducati and the Triumph all using Ohlins front forks, neither does Ohlins when they are building forks for this class of bike.
Excellent thanks. The Kove 450 runs YU-AN forks which are a direct copy apparently, to a SHOWA design. Using your info above, I'll try to crossover the details to suit accordingly. Thanks
