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Jobu137
12-16-2006, 06:02 PM
Recently replaced the stock Ohlins valving in my forks with the Ohlins superbike upgrade kit. I set the oil level at 100mm. While the high speed compression/dampening is much improved, I am now bottoming my forks when under hard braking. Do I need new springs? Add more fork oil? I am 9 clicks out on the compression setting. When I add more comression the ride really starts to suffer. Any ideas?
Any help would be appreciated.

Scary
12-16-2006, 06:15 PM
Sounds like u need to re-set rider sag,.... I would be adding more spring pre-load pressure if u are able(if the adjusters aren't bottomed out) .

Jobu137
12-16-2006, 06:20 PM
Sounds like u need to re-set rider sag,.... I would be adding more spring pre-load pressure if u are able(if the adjusters aren't bottomed out) .

Scary, I am 2 full turns from being maxed out on preload. I weigh about 180#s so I thought the stock .95 spring was right for me.?

Scary
12-16-2006, 06:30 PM
My knowledge is very limited with you model & others here will help more than I can, but that said the relationship between the static bike sag & rider sag will tell you more about the need or not for new springs, & as adding a little spring pre-load can make a big difference I would try that first. It won't take much adjustment to over come it bottoming I think.
I do run more oil in my Tuono (standard model) front to help over-come the same effect, But you would be better to take further advice from your forum area/owner members here on that mate than I.

PS...sorry, just saw the question mark, yes I'd have thought that spring rate would be close for your weight too.
But bike set-up can effect this too in my opinion.
(ie.) I like to run with the Tuono's back end up to it's max height & front down, also with a 65 profile frt.tyre, so my bikes weight bias is 'more' to the front than most like & to lively in the handling for many. But it makes having a slightly higher rate of spring an advantage. As the Tuonos do for my weight.

ckruzel
12-16-2006, 07:37 PM
the superbike internals should have more of a range of adjustment but it sounds like maybe a spring change is in order

Jobu137
12-17-2006, 01:04 AM
Should I try a 1.0 spring? Is there a chart to determine size of spring for bike and rider weight for a Ohlins fork?

Scary
12-17-2006, 04:07 AM
Only thing I can suggest as there isn't many members on here at present, is do a bit of searching/reading mate("ohlins spring rate",gets results) there's a heep out there, have a look at Clarkie49's input in this thread for input(looks like u could go 95mm).......it doesn't take much of an oil height change to make quite a difference, if the pre- load doesn't get what u need.
I'm the sort that tries everything he's able before spending more $$$ as a last resort.:)

http://www.apriliaforum.com/forums/showthread.php?t=81409&page=6

Try Scott2rides stuff in this one & others for the steep learning curve.....

http://www.apriliaforum.com/forums/showthread.php?t=82506&highlight=ohlins+spring+rate

scott2ride
12-17-2006, 05:00 AM
Ok... we'll get you sorted :D

Firstly, at your weight the fork springs are perfect. So the bottoming is unlikly to be related to your spring rate (95Nm currently as stock).

I assume as you said you replace Ohlins internals with Ohlins Superbike kit that you have Ohlins forks and it is a Factory or an 06 RSV-R. Either way, the fork springs should be fine (unless a previous owned has changed them????)

Anyway, you said the front preload was just 2 turns out from fully in. That seems like the preload is a long way in and I would guess it is causing the bike to ride reasonably high at the front (the RSV handles better being and prefers a little low), and high in the front is likely to cause a little pushing in the front and may cause you to run wide (or feel like it wants to) when exiting corners.

Do you feel like you need to muscle it around to turn?

Also, If the front is sitting to high you will get a lot more weight transfer back onto the rear under accelleration and this will cause the rear to squat more.

Anyway, you may already know this, but contrary to popular belief, increasing or decreasing your front preload does not stiffen or soften your suspension. All it does is alter your ride height. Hence the possible consequence above... (not that you have mentioned it, it's just an observation.

But back to the bottoming thing... I assume you have set your sag front and rear. If so, what is the current measurements for static sag and laden sag at the front?

So... as the bottoming is unlikely to be related to the spring rate in this in case, then what is it?

Could be several things. Compression to soft, fork oil too thin, mid-valve shim stacks fucked up, or to little oil in the forks.

But... You say it bottoms under hard braking.
Firstly, is that based on your 'feel' or do you have a cable tie on the fork and find it sits about 5-8mm from the bottom after hard braking?

Secondly, what sort of hard braking are we talking about here? Are we talking a progressivly applied brake force that grows to eventually have the rear wheel coming off the ground at 100mph, and that causes it to bottom.

Or any hard ride which results in some hard braking when setting up for a corner?

Or does it only bottom at 20kph when you slam on the front to do a front wheel stoppie?

Your answers will help diagnose the problem... but here is some bits to consider while typing your reply.

Compression. With the revalve kit and assuming they installed the correct weight oil, then 9 clicks out from fully in is likely to be reasonably firm compression. So is it firm? (That was a subjective question I know, but worth a crack...). If you add another 2 clicks of compression does the ride get harsh up front? It should do (if it isnt already)

The bike has over 30 clicks comp so if it was valved and done correctly for you then you should be closer to the midway settings on the road, with 13-15 clicks out. Then maybe 9-11 out for track work. (On bikes with the normal Ohlins internals they would likely be 10-12 road and 8-10 track).

What sort of oil did they use in the forks? If it was Ohlins then it is about a 2.5 weight. But Ohlins dont grade their oils like others so if the tech has used another brand, because Ohlins oil wasnt availiable or because they wanted to save some money as the Ohlins is bloody expensive oil, then that could be the problem. If they used another brand they should have used a 5 weight.

Your oil height at 100mm sounds about right for you assuming that was measured with the spring OUT!!!! Was the spring in or out when they took that setting?

I had a similar problem of bottoming (I also have revalved forks), but I only bottomed out at the end of a long straight at the track and my rear was fully in the air at this point. I tried fixing with more compression, and to a certain extent that did work. But the front became a little harsh and it was crap when back on the road again. I solved it by adding another 10mm of oil to each fork. then I was able to wind my compression back to less'harsh' settings and not bottom under extreeme braking.

Im a wee bit over 200lbs in my gear and the stock springs are just ok for me. My front is 26mm static sag (bike weight only) and 38mm laden sag (me on bike in all gear in riding position holding the bars). I'd prefer 36 laden but is ok. So you should be fine.

And your mid valve shim stacks should be ok as you have the Superbike kit and that is one of the things the kit addresses.

Hope that helps, or starts the ball rolling.:bump:

Jobu137
12-17-2006, 12:00 PM
Ok... we'll get you sorted :D

Firstly, at your weight the fork springs are perfect. So the bottoming is unlikly to be related to your spring rate (95Nm currently as stock).

I assume as you said you replace Ohlins internals with Ohlins Superbike kit that you have Ohlins forks and it is a Factory or an 06 RSV-R. Either way, the fork springs should be fine (unless a previous owned has changed them????)

Yes I replaced the internals with the Superbike kit. The bike is actually a 02 R. I am the orginal owner so the springs have not been replaced.

Do you feel like you need to muscle it around to turn?

Not really. Feels much improved from before the upgrade kit install.

But back to the bottoming thing... I assume you have set your sag front and rear. If so, what is the current measurements for static sag and laden sag at the front?

25mm and 35mm

But... You say it bottoms under hard braking.
Firstly, is that based on your 'feel' or do you have a cable tie on the fork and find it sits about 5-8mm from the bottom after hard braking?

I have a cable tie on the fork and it will sit almost at the bottom (5mm) after a ride.

Secondly, what sort of hard braking are we talking about here? Are we talking a progressivly applied brake force that grows to eventually have the rear wheel coming off the ground at 100mph, and that causes it to bottom.
Yes

Or any hard ride which results in some hard braking when setting up for a corner?
Yes

Or does it only bottom at 20kph when you slam on the front to do a front wheel stoppie?

Any slow speed "panic stop" will definately bottom the forks.

Compression. With the revalve kit and assuming they installed the correct weight oil, then 9 clicks out from fully in is likely to be reasonably firm compression. So is it firm? (That was a subjective question I know, but worth a crack...). If you add another 2 clicks of compression does the ride get harsh up front? It should do (if it isnt already)

Yes it is pretty firm. Any stiffer and the ride gets harsh.

What sort of oil did they use in the forks? If it was Ohlins then it is about a 2.5 weight. But Ohlins dont grade their oils like others so if the tech has used another brand, because Ohlins oil wasnt availiable or because they wanted to save some money as the Ohlins is bloody expensive oil, then that could be the problem. If they used another brand they should have used a 5 weight.

I used Yamaha O1 fork oil which is a 5wt oil.

Your oil height at 100mm sounds about right for you assuming that was measured with the spring OUT!!!! Was the spring in or out when they took that setting?

I did measure it with the spring out.

I had a similar problem of bottoming (I also have revalved forks), but I only bottomed out at the end of a long straight at the track and my rear was fully in the air at this point. I tried fixing with more compression, and to a certain extent that did work. But the front became a little harsh and it was crap when back on the road again. I solved it by adding another 10mm of oil to each fork. then I was able to wind my compression back to less'harsh' settings and not bottom under extreeme braking.

This is what I am thinking of doing. Maybe 5mm at a time.

Im a wee bit over 200lbs in my gear and the stock springs are just ok for me. My front is 26mm static sag (bike weight only) and 38mm laden sag (me on bike in all gear in riding position holding the bars). I'd prefer 36 laden but is ok. So you should be fine.

And your mid valve shim stacks should be ok as you have the Superbike kit and that is one of the things the kit addresses.

Hope that helps, or starts the ball rolling.:bump:

Thanks for the detailed reply. I will change it and report back.

Jobu137
12-17-2006, 12:01 PM
I guess my replys are attached to your original text. Sorry still a bit new to this.

Poussin
12-17-2006, 12:54 PM
Same problem a few months ago (but with stock öhlins, not with the superbike one).

I adjusted the oil level @ 85 mm (springs in) : no more bottoming (except on super hard brakings, but it's normal).

I'm about 180 lbs with all the gear.

My front settings :
- preload = 12.5 turns closed from fully out
- rebound = 9 clicks open from fully closed
- compression = 6 clicks open from fully closed
- fork height = 5 lines / 16 mm between the clamp and the fork cap
- static sag = 23 mm
- laden sag = 35 mm

421switch
12-17-2006, 10:17 PM
Did you bleed all the air out of the cartridge damper rods when you replaced the oil? If you don't get all the air out, your fork oil level will not be accurate.

scott2ride
12-18-2006, 04:06 PM
Did you bleed all the air out of the cartridge damper rods when you replaced the oil? If you don't get all the air out, your fork oil level will not be accurate.

Thats a good point! Hopefully the tech who did his work did do this, but for those of you game enough to work on your forks yourself do take heed.

Personally the forks are a prick to do if you dont have the proper tools, so I leave it to the pros.

Jobu137
12-19-2006, 01:08 AM
Did you bleed all the air out of the cartridge damper rods when you replaced the oil? If you don't get all the air out, your fork oil level will not be accurate.


Yes I did bleed all the air out of the cartridge. I just added some oil to put them at 95mm. Too cold to ride today. I will take it out tomorrow and report. Thanks again for all the advice.

scott2ride
12-19-2006, 04:32 AM
do you have special tools to get the top cap back on the fork? Or can it be done with general workshop tools?

Jobu137
12-19-2006, 11:01 AM
I have the ohlins cap tool. You can also do it by backing the preload nut all the way back. This will then unscrew the cap. Not elegant but it works. There is really not too much compression on the spring if you need to take that off as well.