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JeffMon Aug-15-05 10:30 AM

  
"Commando suspension sorting"


  

          

Greetings, well I have some good news to report. The 72 750 is getting better and better, but still not completely happy with the handling.

About 6 weeks ago I bought a used Commando in San Antonio. I have rebuilt the forks (had to replace lower fork tubes) and brake. Once I got the bike running, I put on a set of Avon super venoms. I took it to a specialist for Isolastic shims front/rear, and was told the swingarm bushes were worn, so I replaced the spindle & bushes. Oh, she also got new Hagon shocks.

The bike is tighter now, the cornering is good (between the Avons and the new shocks I am definitely on the right track). But I can still feel some play in the front end. I was riding over a bridge in a strong cross-wind, and felt some wobble (not a tank slapper but bad enough). Also at 35-40 mph, if I take my left had off the handlebar, I can feel wobble in the front end.

My Haynes manual says that the steering head bearings are sealed and should not be replaced (unless there is damage). Of course, 30 years on, I think they are worth a look. Is there a Timken bearing kit available? Or should I just order the bearings & bearing cups and rebuild it stock? How hard is it to replace steering head bearings in a home shop (do I need a hydraulic press) Looking for advice on this. thanks

  

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dynodaveWed Aug-17-05 07:16 PM
Member since Mar 18th 2009
706 posts
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#1. "RE: Commando suspension sorting"
In response to Reply # 0


  

          

You can possibly do this job in a home shop environment.
THe bearings are sealed ball bearings.
There is a spacer tube between the bearings.
They can get damaged and worn in normal use and age.
Rather than a hammer, try a long threaded rod and flat plates to crank them in and avoid ruining them by the forceful pounding of the balls on the races. don't forget the spacer tube...

The head shake is just as likely to be from the "tail wagging the dog".....the rear wheel out of balance or being out of true.
Then the front shakes when the resonant frequency of the frame/wheels will then cause the front wheel/bike to shake usually on deceleration and at the same wheel rotation speed.
For this reason I feel a commando requires extra good wheel/tire components....because of the isos....

  

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JeffThu Aug-18-05 09:48 AM

  
#2. "RE: Commando suspension sorting"
In response to Reply # 1


  

          

Is there a "timken" or tapered-roller steering head bearing available? Or is this even necessary? The steering head has just the slightest "looseness" (from vigorously shaking the fork tubes) but even a little is too much. But they don't feel notchy or gravelly when I am turning. Still would like to replace or upgrade bearings on general principles

I agree with the observation that the rear wheel may be out of true/balance. Noticed they had a couple of "big" weights when they mounted that avon; the weights were not like that with the bridgstone tire (suspicious). I am taking the wheels down for specialist true & balance next week.

cheers

  

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jerrySun Apr-12-09 07:59 PM
Member since Mar 18th 2009
24 posts
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#3. "RE: Commando suspension sorting"
In response to Reply # 1


  

          

Dave, I still have not solved my front fork shudder I described in a post awhile back. You suggested wheel balance. I was just interested in this post of Aug 18/05 (below) of tale wagging the dog. I just noticed the wear on my rear avon tire . It is below the wear indicator on one point and on the exact opposite side there is considerable more tread. Why? And could whatever is going on there be the source of the on and off again shudder (forward and back not oscillation) of the front forks at 60 mph up. (You can possibly do this job in a home shop environment.
THe bearings are sealed ball bearings.
There is a spacer tube between the bearings.
They can get damaged and worn in normal use and age.
Rather than a hammer, try a long threaded rod and flat plates to crank them in and avoid ruining them by the forceful pounding of the balls on the races. don't forget the spacer tube...

The head shake is just as likely to be from the "tail wagging the dog".....the rear wheel out of balance or being out of true.
Then the front shakes when the resonant frequency of the frame/wheels will then cause the front wheel/bike to shake usually on deceleration and at the same wheel rotation speed.
For this reason I feel a commando requires extra good wheel/tire components....because of the isos....)



  

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