Clearance problems.......solved (Suspension setup)

SuperDuke-DK

SuperDuke-DK

I previously had some problems with ground clearance during track days. Especially the right side was a problem. Engine cover and exhaust headers was 'dragging' a bit.

On the first two track days, i used the factory recommendation for 'Sport setup'. This is only a guideline, because not every fork and rear shock have same caracteristics. (no rider bodyweight compensation etc.)

By investigating the setup more carefully (checking static sag etc). I found out that my rear shock spring preload was to soft, and rear rebound was set to tight.
Imagine what happends then. Spring preload to soft means lower riding height, and when i 'throw' the machine thru some quick corners (with the rebound to hard) the riding height is getting lower and lower, because the rear shock dont get time enough to extend (hard to explain in english...... i hope everybody understand).

I tightened my spring preload, and softened the rebound on the rear shock, and problem is solved for now (and hopefully for good). Lifting the back end also makes the steering more sharp, that would probably help solve my understeering issues (minor problem).

I go on a three day track experiense tomorrow (Assen Holland). I have never been there before, but i feel confident that the problem is solved for now, also on the track.

More to come after the weekend (if there is any energy left...... )
Stupid Luke

Stupid Luke

I have got a feeling that SD comes standard (05 at least) with progressive spring in rear shock. I believe 165/180????

I am sure someone on here will know for sure.

The previous owner of my bike had spent some money at HM racing and one of the things they did was fit a linear spring (180) to rear shock.

If this is the case then what you are trying to dial out with adjustment is the nature of the spring. Progressive springing is a manufacturers solution so that Big fat Cyril can take his big fat missus touring around town centres without coming back complaining he is being bumped out of the seat by a harsh rear shock.

For track use, you would be better off with a linear spring to suit your weight. So that the rear end loads up in a consistent fashion. Cost is about £50 as I recall.

As I say I have not seen the original rear spring so I am only surmising. But I know for a fact I have a 180 linear spring fitted to mine by H&M and do not suffer the problems you are experiencing .
SuperDuke-DK

SuperDuke-DK

Post missing.

Stupid Luke

Stupid Luke

Post missing.

SuperDuke-DK

SuperDuke-DK

hello everybody,
i think that setting rear suspension was wrong ,the next i will disassembly and i will modify the setting.
the problem was that shock absorber didn't copy the street and it is very hard like damping
i have subgestion about setting front front.
i modified internal valve in the front forck and i have got a good feeling .
here the bill :
compression my proposal:
piston
24x0.2 (2 pcs)
22x0.2
20x0.2
19x0.2
16x0.2
14x0.2 (2pcs)

standard compression ktm setting
24x0.1 2pcs
20x0.1
24x0.1 3pcs
22x0.1 2pcs
18x0.15
16x0.15
14x0.2
18x0.25
10x0.3


rebound
24x0.15 (7pcs)
16x0.2 (2pcs)

sprig rate 9.5 N/mm (my weigh is 85kg)
oil 7.5 SAE
bye
marco