High speed wobble... :O

Loose steering bearings surely will vibrate, thus causing a wobble, not a weave.

And I didn't say that overtightened steering bearing were the cause, just that they might be.

Do a search for GPz750 FAQ, it's covered pretty thoroughly there.

Loose steering bearings surely will vibrate, thus causing a wobble, not a weave.

And I didn't say that overtightened steering bearing were the cause, just that they might be.

Is there a way to check a overtightened steering bearing beside loosening the steering and re-torque to correct setting?


thanks steell!

regards,
laurent

I can see where tight steering bearings would cause a weave. Loose ones would be free to go from full left to full right. There you will get the tank slapper. On the other hand, tight bearings should act like a tightened steering dampner but to a lesser degree. Forks wouldn't go from left to right as quick but the tighter bearings might transfer the action back into the frame and that would get the bike to weave beings the front wheel isn't able to dissapate the back and forth action of the front wheel.

ELCouz wrote:

Loose steering bearings surely will vibrate, thus causing a wobble, not a weave.

And I didn't say that overtightened steering bearing were the cause, just that they might be.

Is there a way to check a overtightened steering bearing beside loosening the steering and re-torque to correct setting?


thanks steell!

regards,
laurent

Please keep in mind your bike may be completely different than this, but below are the instructions for checking the steering on the 1977 KZ650. These are from the Kawasaki Service Manual. I suggest you find the correct manual for your model before adjusting the steering to make sure you have the correct instructions for your bike. The torque value listed for the 1977 KZ650 "Steering Stem Locknut" is 19.5 - 24 ft lb and for the "Steering Stem Head Bolt" it's 29 - 36 ft lb.

Thanks 650ed ! I do have the FSM for my model but its out of reach now , i will check on my pdf version


I have a million dollar question ... how do you torque properly (at the correct torque settings) with a steering nut wrench !!!!?





Thanks

laurent

I adapted the steering stem lock nut spanner wrench so I could torque the nut to specs. I started by drilling and tapping 2 holes in a flat bar and drilling holes in the spanner to match. I bolted the spanner to the flat bar and center punched a spot 7” from the spanner lug (where it would center on the steering stem locknut). I drilled a hole there and filed it square to match my 3/8” torque wrench. The added length adds leverage so you MUST calculate the appropriate torque wrench setting to achieve the correct torque on the steering stem locknut, otherwise you will overtighten the nut. Here’s the formula:

TA x L

---

= TW
L + A

L = Effective length of the wrench as described below.

Dial Wrenches = The measured distance from the center of the square drive to the center ring or notch on the handle.

Micrometer Wrenches = The measured length from the center of the square drive to the center of the handle, with the wrench set at the desired torque reading

A = The measured length from the center of the adapter drive to the center of the wrench square drive.
TA = (Desired Torque) The torque value designated for the fastener with or without an adapter.
TW = (New Setting) The torque setting on the wrench allowing for the added length of the adapter. This reading will be lower than the desired torque.

In my case, using the 7” spanner/adapter, and desiring 260 inch pounds of torque on the steering stem locknut, the formula looks like this:

260 x 8.17

---

= 140.0
8.17 + 7

(8.17” was the effective length (L) of my torque wrench when dialed in for 140 in. lbs.)

So, I set my torque wrench at 140 inch pounds to apply 260 inch pounds of torque on the steering stem locknut. Your numbers will be different depending on the length of your wrench and adapter and the amount of torque you desire.

I HIGHLY recommend you take a look at the CDI Torque Wrench site. They give a detailed description of the use of torque adapters - which is what the spanner actually is. Go to

www.cditorque.com/

click on “TORQUE FACTS” then select “USE OF ADAPTERS.”

Here's what I made and used:

Wow very nice adapter there 650ed!

I would go the lazy way (no maths hehe) !





Its amazing what you can do with a dremel and patience

regards,
laurent

oops i just realized that the socket wont work on my bike

gotta go your way!

have a nice day,
laurent

My Z1B gets a weave. Most noticably on high speed curves, it wanders. I had a pretty bad weave once on the highway going straight doing about 80mph. I think I changed the fork oil and that helped. BTW - my bike has new tires, new tapered stem bearings, new aftermarket shocks and a tight swingarm. I need to get the wheels balanced, although they are true.

Most noticably on high speed curves

Yes right on! It started in a long curve at high speed...

Keep your stories coming, it give me points to look for

Look likes those bikes where prone to weaving, maybe it was not fully understood by bike maker at the time!

best regards,
Laurent

Yeah, these bikes (especially Z1s over KZs) are prone to wobbles. Get a frame bracing kit and thicker motor mounts. Throw on a steering damper if you'd like too. Definitely get the wheels balanced too.

The Z1s used thinner gauge tubing compared to KZs and flexed more.