The Robert Taylor suspension thread

[NordieBoy]

Isn't that where 1000 $1 coins turn into an Ohlins shock?

[Hitcher]

I think it's time to consider an Ohlins replacement for the FJR's rear suspension. It seems to be getting a bit tired after 37,000km of effort. I'm getting a bit of skip and chatter when pushing on out of roughish corners that I can't seem to iron out with a Leatherman and a 7oz hammer.

[cowpoos]

Tell me then about this ''coin trick'' .

I think he maybe be refering to a comment I've heard in the past...about using a coin in the valve on the bottom of the forks of some of the eighties sportsbike with anti dive front forks...that the anti dive works when brake pressure is applied...and the coin is used to stop the system from working bcause it was apparently a crap system that was gard to ride with???

[The Pastor]

Ok here is where i found out about it

http://mootavic.olilolo.com/mods/forks.html

basicly


The first thing to do on assembly is to now lower the front wheel to full travel. Next you fill the fork tubes up to 80mm from the top. I was going to replace the 10W oil with 15W, because it would harden my suspension but i decided not to, instead i used the 10W as specified. However i did add some preload to the spring by using the age-old coin trick. All you do is lift the front of the bike so there is no weight applied to the forks, i used my winch and a open the top fork caps and add 20c pieces [one per side] till you get the desired preload effect. For a fairly light person like myself [65kg], 3 coins makes the rebound noticeably quicker. For a heavier person you might want to try more. I also raised the forks in the triple clamps slightly to drop the front end.


It worries me that no ones heard of it before?

[Hitcher]

Enough with the Teletubbie jokes already.

Presumably Mr Ohlins makes a rear set for an FJR1300?

[Robert Taylor]

Ok here is where i found out about it

http://mootavic.olilolo.com/mods/forks.html

basicly


The first thing to do on assembly is to now lower the front wheel to full travel. Next you fill the fork tubes up to 80mm from the top. I was going to replace the 10W oil with 15W, because it would harden my suspension but i decided not to, instead i used the 10W as specified. However i did add some preload to the spring by using the age-old coin trick. All you do is lift the front of the bike so there is no weight applied to the forks, i used my winch and a open the top fork caps and add 20c pieces [one per side] till you get the desired preload effect. For a fairly light person like myself [65kg], 3 coins makes the rebound noticeably quicker. For a heavier person you might want to try more. I also raised the forks in the triple clamps slightly to drop the front end.


It worries me that no ones heard of it before?

And it needs to be despatched right back to about 1950 or so, this is 2007 and we are supposed to be more sophisticated!!!!

[NordieBoy]

And it needs to be despatched right back to about 1950 or so, this is 2007 and we are supposed to be more sophisticated!!!!

Nowadays it's plastic piping you cut to the appropriate length - much lighter.

Although my XR has a pair of 15mm thick nuts pre-loading the forks and the extra weight helps keep the front down.

[Robert Taylor]

Nowadays it's plastic piping you cut to the appropriate length - much lighter.

Although my XR has a pair of 15mm thick nuts pre-loading the forks and the extra weight helps keep the front down.

I have seen plastic piping shatter, alloy or thin section steel is much more suitable

[NordieBoy]

I have seen plastic piping shatter, alloy or thin section steel is much more suitable

Not sure what type but my DR650 Eibach springs came with some plasticy pipe to make pre-load adjusters from.

[Robert Taylor]

Not sure what type but my DR650 Eibach springs came with some plasticy pipe to make pre-load adjusters from.

That is a very thick wall plastic but I can see a few hurrying off to a hardware store and purchasing tube that is anything but suitable.....

[NordieBoy]

That is a very thick wall plastic but I can see a few hurrying off to a hardware store and purchasing tube that is anything but suitable.....

Surely they wouldn't do that?
Only a real cheap bugger would even think of...

Oh, I see your point.

[F5 Dave]

Which apart from being a horrid thought, isn't how you ride your bike anyway. I'm over 80kg with my leathers & helmet, decent protection is heavy.

Reviewing above, maybe my specialising in racing 50cc bikes is a bit foolhardy. Ah well.

[limbimtimwim]

I know Robert is away for awhile, but I thought I'd put this out there anyway. This is in reference to my DR-Z400SM.

So when I change directions on this bike quickly, the bike feel likes it is about to slap. It doesn't quite, but I can feel it is getting close. Especially under acceleration. I can accept this is exactly when I'd expect this to happen, but I'd like to minimise it to the fullest extent.

At the races on Sunday I had the comment from someone that perhaps there was not enough rebound damping, and it was visable when I changed direction that the rear suspension was quite loaded before the direction change and during it very quickly unloaded.

Anyway, it meant that I had to moderate my inputs a little otherwise the bike got a bit upset.

And a couple of times out of corners I had the front sliding a bit. I think more weight on the front wheel might help remedy it.

So how do I approach sorting this?

Do I minimise the compression in the first place so that the suspension has less travel to rebound through? Or do I slow down the rebound? Especially at the rear?

My thinking is to do both, at both ends. Ie. Increase everything, preload, compression damping and rebound damping. But not go crazy with the twiddlers. I can hear Robert telling me the stock adjustment only works along a very finite range about the centre of all the adjustments.

[F5 Dave]

I think you need to be careful with your descriptions, I was about to say no that's the wrong thing entirely, but then realised "What does he mean by minimise?" - Is it minimise the amount it compresses?, or minimise the settings? hence wind comp off.

Anyway my initial reaction is within the bounds of what a really long travel bike is like on the road (ie: compromised), if you wind off the compression damping the bike will tend to feel unsettled when flicking from side to side. Try it over a stretch of road & then see if it gets worse if you then wind it off. Then wind in some more until it gets better.

Problem is with crude suspension too much compression damping is a bad thing esp for stutter bumps, esp high speed damping which is often hard to separate. But you should at least be able to find which way to go, if only to a closer compromise. I'd then try some more rebound damping if it is still springing back quickly, after first experiment on a decent section of road with some transitions.

[TDC]

I know Robert is away for awhile, but I thought I'd put this out there anyway. This is in reference to my DR-Z400SM.

So when I change directions on this bike quickly, the bike feel likes it is about to slap. It doesn't quite, but I can feel it is getting close. Especially under acceleration. I can accept this is exactly when I'd expect this to happen, but I'd like to minimise it to the fullest extent.

At the races on Sunday I had the comment from someone that perhaps there was not enough rebound damping, and it was visable when I changed direction that the rear suspension was quite loaded before the direction change and during it very quickly unloaded.

Anyway, it meant that I had to moderate my inputs a little otherwise the bike got a bit upset.

And a couple of times out of corners I had the front sliding a bit. I think more weight on the front wheel might help remedy it.

So how do I approach sorting this?

Do I minimise the compression in the first place so that the suspension has less travel to rebound through? Or do I slow down the rebound? Especially at the rear?

My thinking is to do both, at both ends. Ie. Increase everything, preload, compression damping and rebound damping. But not go crazy with the twiddlers. I can hear Robert telling me the stock adjustment only works along a very finite range about the centre of all the adjustments.

The order you should approach bike suspension adjustment in is:

Spring Rate
Geometry
Rebound damping
Compression damping.

Spring Rate - Unless you have the correct spring rate for you body weight and usage everything else is bigger compromise that it needs to be / should be.

Geometry - Is the attitude of the bike correct, nose up nose down etc etc

Rebound damping - The most misused adjuster on suspension in the world! Start by setting your rebound adjuster so that when you give the front suspension a big bounce and then let it go (sans stopping the bike from falling over) the suspension should return smartly and just overshoot at the top by 1 - 5mm. Then bouncing the bike by weighting the foot peg so that both the front and rear suspensions are exercised, adjust the rear rebound adjuster so that so that rear suspension visibly has the same speed of return as the front. This will give you a good place to start.

Compression damping as much as you can have without getting too harsh would be a good place to start from.

From you brief description it sounds to me like it could very well be too much rebound in the front.