Ultra harsh on small high speed bumps?

Juicifer · Apr 19, 2012

The bike is an '09 FE570, 1 size stiffer springs front and rear (PDS 7 progressive), otherwise the suspension is stock. My bike rides great but on high speed forest roads (30-50mph) the smallest bumps are incredibly harsh, and painful! I thought this was normal but my friends KTM 505 does not have this problem. How can I tune this out? What causes this? Is there anything I can try besides a full revolve?
Thanks!

Ruger · Apr 20, 2012

I am no suspension expert, but I know that more information is needed to answer your question. What's your weight including riding gear, what are the specifics on those springs, and how do you have the dampers adjusted?

Juicifer · Apr 20, 2012

190# with gear, and all the clickers are at about the "sport" settings in the manual, maybe one click stiffer on the compression front and rear.

Chas · Apr 20, 2012

It sounds like the first thing you need to do is to back off the damping adjusters (decrease the damping) front and rear, especially the compression damping.

Noppy · Apr 20, 2012

Perhaps check with a centimeter the length of the air chambers and check for trapped air in the forks. I bleed my forks after every ride.

Taffy · Apr 21, 2012

Ruger said:
I am no suspension expert, but I know that more information is needed to answer your question. What's your weight including riding gear, what are the specifics on those springs, and how do you have the dampers adjusted?

then don't answer the question then?

I don't discuss Fi here or a host of other stuff. if I don't know it i DON'T ANSWER IT. MIND YOU - i HAVE BEEN KNOWN TO HAVE A WILD STAB AT IT! :lol: :lol:

for a cheap fix please remove the base compression valve from the forks. you do this by laying the bike carefully on its side and raising the legs so that the bottom is higher then handlebar end. even 2" higher is enough.

remove the comp stacks as I say (19mm) and then with it held in the vice you use a 17mm spanner to to undo the next nut. remove all the shims on a spike etc and spread along the bench. the first shim is 16mm and thick, then a 9.3 and also thick and then the first thin one will be about 10 or 11mm.

you'll have about 6 x 24 at the other end. remove 2. remove this and reverse what you just did.

same to the other leg.

this is a reasonable fix to stop harshness.

regards

Taffy

Taffy · Apr 21, 2012

Ruger said:
I am no suspension expert, but I know that more information is needed to answer your question. What's your weight including riding gear, what are the specifics on those springs, and how do you have the dampers adjusted?

then don't answer the question then?

I don't discuss Fi here or a host of other stuff. if I don't know it i DON'T ANSWER IT. MIND YOU - i HAVE BEEN KNOWN TO HAVE A WILD STAB AT IT! :lol: :lol:

for a cheap fix please remove the base compression valve from the forks. you do this by laying the bike carefully on its side and raising the legs so that the bottom is higher then handlebar end. even 2" higher is enough.

remove the comp stacks as I say (19mm) and then with it held in the vice you use a 17mm spanner to to undo the next nut. remove all the shims on a spike etc and spread along the bench. the first shim is 16mm and thick, then a 9.3 and also thick and then the first thin one will be about 10 or 11mm. remove this shim, the first after the 9.5mm and thick one.

you'll have about 6 x 24 at the other end. remove 2. remove this and reverse what you just did.

same to the other leg.

this is a reasonable fix to stop harshness. you'll have soft suspension perhaps but this is a simple start.

regards

Taffy

nick790 · Apr 21, 2012

Taffy said:
Ruger said:

I am no suspension expert, but I know that more information is needed to answer your question. What's your weight including riding gear, what are the specifics on those springs, and how do you have the dampers adjusted?

Click to expand...

then don't answer the question then?

I don't discuss Fi here or a host of other stuff. if I don't know it i DON'T ANSWER IT. MIND YOU - i HAVE BEEN KNOWN TO HAVE A WILD STAB AT IT! :lol: :lol:

for a cheap fix please remove the base compression valve from the forks. you do this by laying the bike carefully on its side and raising the legs so that the bottom is higher then handlebar end. even 2" higher is enough.

remove the comp stacks as I say (19mm) and then with it held in the vice you use a 17mm spanner to to undo the next nut. remove all the shims on a spike etc and spread along the bench. the first shim is 16mm and thick, then a 9.3 and also thick and then the first thin one will be about 10 or 11mm. remove this shim, the first after the 9.5mm and thick one.

you'll have about 6 x 24 at the other end. remove 2. remove this and reverse what you just did.

same to the other leg.

this is a reasonable fix to stop harshness. you'll have soft suspension perhaps but this is a simple start.

regards

Taffy

16mm thick shim!!! I'd remove that for a start :wink:

Juicifer · Apr 21, 2012

I've never messed with the shim stacks before, but maybe it's time. If its that easy to tip the forks up and make changes I'll try it. No special tools necessary or messing with the fork oil?

Taffy · Apr 23, 2012

Juicifer said:
No special tools necessary or messing with the fork oil?

I'd have told you if you needed it.

you talked the talk now walk the walk 8O 8O

regards

Taffy

Tonibe63 · May 1, 2012

Taffy said:
remove the comp stacks as I say (19mm) and then with it held in the vice you use a 17mm spanner to to undo the next nut. remove all the shims on a spike etc and spread along the bench. the first shim is 16mm and thick, then a 9.3 and also thick and then the first thin one will be about 10 or 11mm. remove this shim, the first after the 9.5mm and thick one.

you'll have about 6 x 24 at the other end. remove 2. remove this and reverse what you just did.

same to the other leg.

this is a reasonable fix to stop harshness. you'll have soft suspension perhaps but this is a simple start.

regards

Taffy

Would the above apply to my 2010 fe390 forks Taffy?
I only trail ride but the Husaberg forks have always felt very harsh on rocky trails like The Wayfairers near Oswetry, Rudland Rigg in Yorkshire etc. I've tried backing out the compression clickers but it's still very harsh giving bad arm pump.

Taffy · May 1, 2012

I'm only talking open cartridge forks here and if that is what you have then yes it's valid

regards

Taffy

Taffy · May 1, 2012

so you're removing three shims

2 x 24 on the front and a 10 or 11 at the back. the first one after the really thick one which will be a 9.5-9.75 by 0.3mm.

regards

Taffy

Tonibe63 · May 1, 2012

Taffy said:
so you're removing three shims

2 x 24 on the front and a 10 or 11 at the back. the first one after the really thick one which will be a 9.5-9.75 by 0.3mm.

regards

Taffy

Yes, understood.
(I misquoted you in my question, Doh, but have now edited it)

Manual says forks on my 2010 fe390 are:-
4860 MXMA PA
which I believe are open cartridge (Rebound clickers at the top and compression clickers at the bottom).

Thanks.
Tony

fe600racer · May 16, 2012

Hi guys, how about some feedback after removing those shims. Did it do the job?

Also has anyone experimented with the size of the holes some of us have drilled into the cup at the bottom of the forks to allow more travel for those that don't need that resistance as they do not do motocross big front wheel landings: ie getting more suspension travel on big woops etc? I followed Taffy's advice and the Doc, and it worked well, but I am thinking of making those holes a bit bigger to get a bit more travel over woops.

tazer · May 16, 2012

I had the same complaint.

I weigh 65kg and run the stock springs at 3 turns pre-load.
I removed six shims from each fork leg to get a less harsh ride.(See photo)
This made a massive improvement for me.

I hope this helps.

Steve

Tonibe63 · Jul 3, 2012

fe600racer said:
Hi guys, how about some feedback after removing those shims. Did it do the job?

I did the shims, fitted 2 sizes up on front springs (fb) and refilled with fresh 5wt oil.
First ride out was on muddy rutted lanes and immediately the front felt a fair bit softer but I left it alone and just rode it to bed it in.
Last weekend I rode on rocky trails which is where I'd previously had problems. Clickers top and bottom left on standard settings and the really harsh feeling felt much better although still deflecting slightly, so it's gone the right way and should improve more with a bit of clicker twiddling. My main concern was the front was now pushing out on muddy turns which improved a bit after adding some rebound damping.
I'd got the forks set about level with the top of clamps so think I will push them up to the first ring for my next ride in a couple of weeks.
The greatest benefit was that I wasn't gripping the bars so tight which mean't no arm pump all day=result :cheers: .

olpace · Jul 3, 2012

mine is very harsh as well, but someone has done suspension work to it, it has a sticker on the forks in relation to the guy that built the suspension. I guess I need to call him and see what he did to it, the guy I bought it from said he paid a thousand dollars to have suspension work done....??? all I know is going across small bumps in a pasture in 3rd gear it will take the handlebars right out of your hands (throw you into a wobble that cannot be prevented hardly) the suspension on the front is very stiff. suggestions? I am 5' 9 180lbs

Juicifer · Oct 18, 2012

I'm finally getting around to doing this mod, but I'm stumped on the very first real step. I removed the fork legs just to make it easier. I pried the dust cover off the bottom, slapped a 19mm socket on the compression end of the fork, and turned, and turned, and turned, and turned, and turned. Nothing happens other than a few squeeking noises, but the assembly is definitely not threading itself out of the fork leg. It doesnt feel like it is stripping anything either, just a steady pressure on every turn. I've also backed out the compression and rebound clickers, and bleed the air out of the chamber.

I'm the original owner of the bike, so I know it hasn't been messed with before, and it didnt feel like I damaged anything either. What the heck am I doing wrong, it seems so simple but nothing happens when I try to unscrew the compression assembly. :angry:

steve · Oct 19, 2012

Juicifer said:
I'm finally getting around to doing this mod, but I'm stumped on the very first real step. I removed the fork legs just to make it easier. I pried the dust cover off the bottom, slapped a 19mm socket on the compression end of the fork, and turned, and turned, and turned, and turned, and turned. Nothing happens other than a few squeeking noises, but the assembly is definitely not threading itself out of the fork leg. It doesnt feel like it is stripping anything either, just a steady pressure on every turn. I've also backed out the compression and rebound clickers, and bleed the air out of the chamber.

I'm the original owner of the bike, so I know it hasn't been messed with before, and it didnt feel like I damaged anything either. What the heck am I doing wrong, it seems so simple but nothing happens when I try to unscrew the compression assembly. :angry:

Try a rattle gun and/or compressing the forks as much as possible to get more load on the cartridge when you are doing it. Forks upside down is the go too.

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Ultra harsh on small high speed bumps?

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