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Wobble after new Avon Venom install

M

MSRev

Scooter
It shows at 40-45mph. I have not done a thing to the front of my 99 C-10 other than bearings in 72k. I have read the threads and I will check the fork pressure and then the steering head. Is this the route I should take?

Also, I have run OE and 205 Dunlops to this point.

Pastor Tyler
 
Well, if you got a 99, gonna have to skip the fork pressure...but you can check the rear shock pressure.
Try reinstalling the front wheel and check the steering head.
 
I knew that!! Brain cramp. Thanks for the reply. I did notice he was having a problem or it seemed he was in getting the front wheel axle to align. This guy is an experienced tire man.

Pastor Tyler
 
MSRev said:
I have not done a thing to the front of my 99 C-10 other than bearings in 72k.
Click to expand...

Wow! Time to change the fork oil and re-grease the stem bearing. And many have reported eliminating the wobble by tightening the stem bearing nut, that might be your problem. From what I have read it is more noticeable with the Avons.
 
one thing at a time....adjust the head bearing.
don't do 3 or 4 different things simultaniously, it breaks every rule of correct diagnosis, and you will never know if one was the culpret. Make one change at a time.
 
Yep, the head bearing gets the nod. I have read chalkdust and the various threads on the forum and now it is off to get it done.... wait....is there a tech session at the National??? ;D

PT
 
Tyler,
For what it's worth, I did not have this problem when I went to the Venoms. I agree with Rich...check the head bearings as this seems to be a particularly sensitive item when it comes to tires. Good luck. See you in Vermont.

Eddie
 
Was the wheel and new tire balanced? 

I've had several Avons, all good tires, but all difficult to get properly balanced.  I spin my own and have had to reposition tires on a couple to get the wheel balanced properly with under 2 ounces of weights. If I have to place 2 ounces of weights on any wheel I re-spin the tire to find a better balanced position. The less weights the better, but I've never had an Avon without some balancing issues.
 
2linby brings up a good point about wheel balance. I too have had to use much more weight than I thought necessary to balance front Avons. One significant point also is to make sure that the wheel is properly dynamically balanced. On my trip back to Frisco for the 2008 Nationals I had a subtle wobble on a newly installed Storm. It turned out it was properly balanced statically but all of the weight was on one side of the rim. I divided the weight and placed even amounts on each side. Problem solved.

Here is my method for checking steering bearings:

I have found a more accurate way of determining head bearing looseness. I sit on the bike, off the center stand and clamp the front brake on. With the index finger of my left hand bridging the gap between the upper bearing oil seal (the round black piece just below the upper triple clamp in this picture):

2780736940053667879S600x600Q85.jpg


and the frame tube, I rock the bike back and forth slightly and feel for any movement between these two parts. All it takes is a very slight rocking motion to detect movement. If anything is felt here, the bearings need tightening.

I have always had difficulty feeling movement with the front wheel off the ground although I still try that first. The brake-on, rocking back and forth is very clearly felt. This method also places the weight of the motorcycle on the lower bearing set which more accurately reflects the load during riding.

Dan
 
Got around to checking the head bearing and it was the culprit. I would starve to death if I got paid by the job. It took me alot more than 30 min. to get it done. Now I can let the bike slow down and stay straight with no hands from 50mph to say...20mph with no wobble.  :)

I did have a pleasant surprise. I thought I remembered seeing a strange wrench in the tool pouch and to my surprise it was a GEDORE 40-Z spanner wrench from the PO.

Thanks for all the help. I would be lost without the knowledge that is here on this forum and the willingness of a great group to share it.

I hope to see some of you at the National.

Pastor Tyler
 
What do I need to use as a yardstick (+,-) for my speed odometer now that I have venoms on the bike?

Pastor Tyler
 
Tyler, running the Venoms on my bike, I've found that the speedo is about 1 - 2 MPH slow compared to the GPS.

Eddie
 
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