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Discussion Starter · #1 ·
Edit: I have posted the same question in some other forums and there seems to some confusion about the words "pogoe/swirls"......sorry my english not always that good

What I mean to say is the bike is unstable under hard braking as in a very very slow moving slapper. It feels like the forks are moving in a slow slalom like fashion.
I have just fitted the Rennsports and I can not recall the bike doing this with other tires, but I am not sure cuase I never really tried such hard braking as today


Took my K2 for a afternoon ride and decided to test out some really hard braking from speeds @ +200 km/h and the bike pogoes or moves like a snake at the front like slow swirling movement.
I have seen the 600 supersport bikes do similar coming hard on the brakes before a certain corner at last race in Monza, but this feels like it is different.
I am going to check it out tomorrow, but could it be that i have different settings on each forkleg? I hardly doubt it.

The bike doesn't hop under hard braking and I tried coming onto the rear brak a tad before the front, but it didn't help settling the bike much.

It isn't like I am loosing control over it, but something tells me it shouldn't be like this.
My K5 does not behave likewise.

Any ideas what could cause this?

FYI I am running Ohlins suspension front/rear, newly balanced rims with Rennsport tires, and as the settings are now the bike handles very good.

basic setting front are:

- one turn less preload from stock Ohlins
- stiffened up the comp 2 clicks
- stiffened up the rebound 4 clicks

Rear:
- all settings are at stock Ohlins but stiffened the comp 2 clicks
 

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is the level of fork oil the same in both legs? that may cause a similar effect.

it could also be a sticking caliper causing harder braking on one side of the wheel, throwing off the balance.

just some guesses.
 

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I would look to any difference between the forks. Maybe different springs, oil level like said above. double check settings.. THe tankslapper effect is caused by alternating sideloads on the front tire. your slow weaving effect should be caused by the same. Heaven forbid you have a cracked fork mount....?? one fork higher than the other....
 

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Have you done your sags? My guess is there is a too much weight transfer to the front on hard braking? Maybe too much rear preload/ride height or possibly even the front compression being too soft?

Try another couple of hard stops but really push your bum into the back of the seat when you do it. If it stops the problem this is probably the problem if not it will be something else.

Cheers
MP
 

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Discussion Starter · #6 ·
It is almost a little funny if not embarrasing.

I checked all my settings before todays ride and found that the right forkleg had 3 turns less preload than left......................let the flaming begin

I was like WTF...how come I didn't notice this when riding the bike through the very bumpy twisties here. Still puzzles me that one
Seriously the bike was just fine yesterday besides this weaving thing at the front....believe me or not.

I had a look at the rear end, actually I inspected the whole bike and when lubing the chain I found the rear brake was dragging heavily. It turns out that the spring on the brakelever (Harris rear sets using OEM spring) is not strong enough to bring back the lever to resting position and therefore were still pushing on the mc. Fixing the lever in a more lower position fixed that.

Anyway, I dialled in the correct sag (preload) and the other settings and to no surprise the weaving effect is gone. Feels fine now, only some normal weaving when the rear is just skidding over the asfalt.

No wonder I had some moments yesterday, with an uneven preload and a rear brake that was dragging quite a lot .

I also set the pressure to 32 front and 36 rear which seems to be good for the tires. Could feel the increased grip, though not very noticable. I think I'll settle for a bit higher.

Again thanks for beeing with me on this one guys.

 

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glad you found out what was wrong!
 
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