Wobble

[Crotch Rocketeer]

Hi all,

OK, when I bought my bike (2001 Kat 600, 30k mi) it had a slight instability when I would take my hands off the bars on the highway. Then, I replaced the the wheel bearings (both axles) and the wobble became a lot stronger. So, in an attempt to find the problem I have rebalanced the wheels, adjusted the steering head bearing and retorqued the swing arm pivot bolt and it hasn't made any difference. Yes, my shocks are all set equally.

The bike rides smooth as glass (I can feed almost no vibration in the handle bars on the highway), but when I get between 50-60 mph the bike becomes unstable until I accelerate past 65 mph, then it feels like the handle bars are bolted in place.

I adjusted the steering head bearing according to the manual (between .5 and 1lb of pull force to move), but now the bearings feel slightly notchy. Other than this, I haven't been able to find anything wrong. Any ideas what is going on or what else I should check? Thanks

[jetmerritt]

Bad tire? Check the runout on the tires. Spin them and see if you can see any variation of the surface, it doesn't take much to cause vibrations. Balance wont fix poor runout.

[arsenic]

Could be a number of things. Replacing the steering stem bearings would be my first course of action. Followed by the front wheel bearing. Next I'd change the fork oil and be sure both forks are equal to the specified amount. I recommend All Balls bearings for both the steering stem and front wheel. After making sure the tire is good of course. I assumed you already did that.

[Crotch Rocketeer]

I haven't checked the runout on the tire but the bike is so smooth (before and after the "wobble zone") that it seems unlikely to me. Already replaced all wheel bearings (All Balls kits are awesome, great quality and price). I have no idea what the condition of the fork oil is.

I think it is the steering bearings, they don't feel right to me. They aren't terribly expensive, I think I'll start there.

Are steering bearings normally worn out at 30k miles?

[arsenic]

OE steering stem bearings suck large farm animals. Get All Balls steering stem bearing too. Warning steering stem bearings are not as easy to change as wheel bearings.