steering wobble

Hi I have an xj750rj and I've had a pretty noticeable wobble in my front end, especially around turns and corners. Turning from a complete stop is pretty unstable too. I've checked the front end and the axle and made sure everything is tight. I've read on other sites that it could be a bad steering stem bearing? Is it possible to tighten that up or should I replace them?

 

There is a nut you can tighten. I don't have your bike but on my 550 Maxim you have to pull the handlebars and upper steering bracket to get to this crown nut. Chacal sells a tool for the "special shape nut" but I think some people whack it on the side using a screwdriver. I got the tool.

Tightening this nut is probably worth a try, but if the side-to-side turning is still rough with 'catch points' (test this on the center stand) you would have to minimally clean/re-lube your bearings. If they are shot you'll have to replace them. I just replaced mine (Maxim 550, upgraded to tapered roller bearings) and I'll post a how-to when I have the time to get it together. It's kind of a pain... worst parts were extracting the races and pressing on the new ones... I had to improvise some presses and drifts. A how-to would have helped me immensely, but it's the kind of thing where once you're doing it, it makes more sense.

 

Don't bother tightening the head bearings. The grease is 30+ years old, as are the bearings. The races are likely notched from lack of lubircation. The best course of action is to replace the factory bearings with a set of roller bearings.

One key bit of advice when fitting new bearings: The torch and the freezer are very, very good friends. Use physics to your advantage. Freeze the steering stem and heat the bearings. Freeze the bearing races, and warm the steering neck. Everything will just slide into place.

Bearing removal will require the use of a hammer and a brass drift.

 

OK cool. Yea I'd rather just replace the old parts if need be. Any recommendations for aftermarket bearings? And do you think this would be the cause of my wobble? Seems like the only thing that makes sense

 

Only other thing I can think of is an unbalanced tire maybe

 

The only other possabilities are wheel bearings, and swingarm bearings. If it were just a wobble at speed I'd suspect a problem with the rear shocks too. Since you described it as being unstable even at low speeds then that points to the steering head bearings as the primary suspect.

Are the forks in good shape? Do they slide smoothly, without any slop?

Send a PM to Chacal. He has everything.


What work have you done to catch up on deferred maintenance?

 

Yup forks are good I just replaced the oil and dust seals on both and so far so good. Other than that I've replaced an oil gasket, filled her with oil and bled the brakes back to normal. That's about it

 

Hoping to Bob it out this winter, to an extent

 

Worn out rear shocks can cause "head shaking" at any speed.

Put the bike on the centerstand and prop up the front end (a jackstand between pipes #2 and #3 under the frame crosstube works well.)

Kneel in front of it and grab ahold of the front forks, and pull/push them back and forth to check for looseness in the steering head bearings.

With the front end still in the air, center the handlebar and then gently push it off center, first one direction and then the other. The bar should fall smoothly to the side, and there should be no discernible "detent" in the straight-ahead position.

If simply loose, yes the locking ring can be tightened. If you have a "center detent" then the races are trashed. If the bars do not move smoothly then it's time for new bearings.

 

On mine I have a bit of a clunk on the bars at every bump on the road. I just rebuilt the forks (and put air in the forks). When I put the bike on the center stand, the bars fall very quickly, not smoothly. Are they classic symptoms of loose steering head bearings?

 

Cool, thanks for the input. Im definitely going to try that front end test. Another question, is it bad to be riding around like it is? Or is it just more of a nuisance? I dont want to kill myself lol but I am used to the wobble, im just annoyed with it. But of course dont want to stop riding

 

It is indeed dangerous.

"Wobbly" handling also means erratic TRACTION and you only have two wheels making contact with the road.

If you're going to continue to ride the bike, diagnose and be VERY aware of the condition that is causing it and what you can do to hopefully mitigate the negative effects. Meanwhile, stay out of heavy traffic and any other situations requiring your equipment be 100% to keep you from being squashed.

It's not just a nuisance. It's a symptom of something that you need to attend to.

 

^^ What Fitz said.

Something to consider: If your bike were an airplane, it would be grounded until repaired and inspected. Motorcycles are much closer to airplanes than to cars, in terms of the consequences of mechanical failure.

One more tidbit: The last broken ankle that I had to pay for cost me $7k out of pocket, after inurance and negotiated discounts.

 

Right but will it get to a point where it will break completely? Or is it what it is and that's how it will ride until I fix it

 

And I also hear that clunk when I hit bumps. What bearings would you recommend I get?

 

Did you put the bike on the center stand and shake it down front and rear?

Motorcycles are overall simple machines. Shake it down and find the loose parts. It costs nothing and is easy to do.

 

Seriously. DIAGNOSE, don't guess. There are a number of distinctly different potential causes for your problem; the steering head, the forks themselves, the rear shocks, wheel bearings front or rear, the swingarm pivot bearings, or a combination of any of these. Figure out where the problem is.

 

I had a wobble on my FJ. Wiggled everything, found rear wheel loose. Replaced bearings - no more wobble.

Like Fitz said - go wiggle stuff.

 

MIne is pretty stable on a straight line, and predictible in turns, but it acts funny when I do a fast in-and out counter-steering practice move on dry pavement. It is like the bike doesn't want to come back immediately to a stable feeling, hard to describe, it's like i feel an echo on the last move...could it come from the front wheel or the rear wheel as well?

WHat puzzles me is that I can't feel any free play when I wiggle front forks neither swingarm.

 

Do what has been suggested. These guys know what they are talking about. Also might try loosing the pinch bolt on both the front/rear tires and see if the shaft nut is properly torqued. This too could cause wobble and uneven tire wear if eveything is not pulled tight prior to cinching the pinch bolts. Hope this helps.

Gary H.