83 rear shock question

[bkuhr]

Looking at page 5-40 service manual, but can't get it to copy here.

When the bolt that goes thru ARM-1, Relay Arm, and Lower fitting or Rear Shock is tightened down, the shock locks up to ARM-1(does not pivot freely).

 

Can see what is happening, bushings 'G' press into bushing of lower shock and 'lock up'

Bushing of lower shock appears to be molded into the rubber isolator of lower shock.

 

It takes siginficant force to rotate shock around pivot of ARM-1, this can't be correct, can it?

 

Can't figure any way to

1. Keep pressure of bushings 'G' off bushing of lower shock so shock bushing can rotate around bolt shank.(dont think this would be correct for shock to work directly on the bolt) or

2. Allow shock to rotate around lower shock bushing/rubber isolater

 

Removed entire shock/link system due to this issue, installed zerk fittings and lubed. All other pivot points work great.

 

Ideas/ Suggestions?

Brian

[SaltyDog]

Take a look at the attached picture for the lower mounting pivot of the rear shock. There is a collar inside the lower shock eye and it shoild be free to rotate and allow the rear shock to move as needed during suspension travel.

[bkuhr]

now really confused?

metal bushing in rubber isolator(#9) in bottom mounting eye appear to be molded together.

I tried to press metal bushing out, and pressed until rubber isolator looked like it was going to tear-then quit.

metal bushing ID just fits thru bolt

 

brian

[SaltyDog]

The collar in the bottom shock mount is supposed to be greased periodically (yeah right!). But it is rarely done, witness the wide instances of all the bushings in the rear suspension arms being dry and wearing out. Yamaha didn't put any provision for adding grease through grease zerks, so the only way they get lubricated is if you take it all apart and clean, replace and grease the bushings and collars.

 

I had to do just that to my '83 and I replaced all the bushings and one of the collars that had been running dry and wore out. I installed grease zerks on all the pivot points and you can be sure I pump a shot of grease to them whenever I have the bike on the lift or am changing the rear tire.

 

The collar on yours is rusted in place, probably due to lack of grease and it's location behind the rear tire and water spray. Mine was stuck also, but I got it free and cleaned up. I grease it with moly60 grease (should have added a grease zerk here also). The rear shock doesn't rotate much during suspension travel, but it does move.

[bkuhr]

Take a look at the attached picture for the lower mounting pivot of the rear shock. There is a collar inside the lower shock eye and it shoild be free to rotate and allow the rear shock to move as needed during suspension travel.

 

Ok pulled shock again, took pics this time. metal bushing will not press out of rubber isolator. should I keep pressing?

Brian

[dingy]

I just checked the shock I took off m 83.

 

The the isolator and bushing seem bonded together in it as well.

 

Gary

[SaltyDog]

I went out and checked my original '83 rear shock (no spring, only air suspension, non-class) and it appears to have the lower mount bonded also. I had changed my rear shock last year to a Class type (spring/air suspension) last year so I could install a Progressive rear spring and get some more ride height. The shock that originally came on my bike had the compression adjuster broken and sat really low even when aired up.

 

Yamaha apparently figured that with the limited rotation of the shock during suspension travel, it didn't require a rotating collar like the later bikes. The online parts lists and other .pdf parts lists show a moveable collar on the '83 and later bike (first gen). Maybe the non-Class are different than the bikes with the Class system.

 

I bought a Class style rear shock and adapted the Class airline to fit into the bracket along with the compression adjuster. The later shock has a separate collar on the lower shock mount like the parts lists illustrate.

[SaltyDog]

Just remembered a tip that I learned about setting up suspension pieces that use only rubber bushings. Don't torque the through bolt until the bike is down and resting on the supension so the parts are in the "normal" at rest position. This way the rubber mount is locked into a position that allows rotation in either direction (CW and CCW). This insures the rubber bushing won't be over stressed like it would be if it was torqued while in the unloaded position.

[bkuhr]

Just remembered a tip that I learned about setting up suspension pieces that use only rubber bushings. Don't torque the through bolt until the bike is down and resting on the supension so the parts are in the "normal" at rest position. This way the rubber mount is locked into a position that allows rotation in either direction (CW and CCW). This insures the rubber bushing won't be over stressed like it would be if it was torqued while in the unloaded position.

 

Good tip, didn't think about this, thanks.