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Rear upper engine mount, what am I missing?

Started by great white, November 06, 2022, 12:16:37 PM

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great white

I'm putting my 89 fj1200 back together and there seems to be something wrong with the rear upper engine mount. When taken apart, the mount to the frame looked like so:

https://www.hobby-machinist.com/attachments/293bb310-jpg.425783/

Now:

https://www.hobby-machinist.com/attachments/fr_3954-jpg.425784/

can't be frame "spread" and it can't be that the mount bolt is intended to "pull" the rails together, it's just too heavily braced for that.

I gotta be missing something (nothing evident in the parts breakdowns) or I'm just doing something wrong (FSM is of no help)........

red

Cheers,
Red

P.S. Life is too short, and health is too valuable, to ride on cheap parade-duty tires.

great white

In a nutshell, The two rear upper aluminum bushings in the frame are not tight to the frame and the engine boss when bolted down. Not sure how else to post pics without creating another account somewhere else....

Lets try this. Before:



After:


fj1289

That seems correct to me - but will defer to Randy and Robert. 

Seems logical for that mount to locate the engine up/down and fore/aft.  Left/right can easily be accomplished by the remaining mounts.  That would also put less stress on the case depending on production tolerances. 

great white

Other pictures on the 'net seem to indicate the bushings are tight to the frame and the engine boss:


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It may be a little hard to see in the original pic (before disassembly) but the pic off the net has the bushings in the same place/clearances (ie: tight to the frame and engine bosses).

I need to figure out what has changed from "before" to "after"....

great white


great white


great white



Sure seems to indicate there's something up with my bike's rear upper mount.....

fj1289

They are different bushings.  The bushings in the "after" picture have very little shoulder - vice the bushings in the "before" picture have a much wider shoulder. 

I'm trying to figure out where the narrow shoulder bushings go (and where the wide shoulder bushings might be now).


great white

Quote from: fj1289 on November 06, 2022, 06:54:18 PM
They are different bushings.  The bushings in the "after" picture have very little shoulder - vice the bushings in the "before" picture have a much wider shoulder.  

I'm trying to figure out where the narrow shoulder bushings go (and where the wide shoulder bushings might be now).



I don't know about that. Theres no other installed bushing on the bike yet that are similar and I've dug all the parts I have bagged and tagged out and didn't see any more. These were also in the bag labeled "upper rear mounts".

I'll go through the bins again tomorrow, but I'm doubtful.

It would super simple for me to just fire up the lathe and make new spacers or bushings to take up the clearance, but I don't want to do that if something is assembled wrong, which seems to be the case here...

fj1289

Funny thing is - my 89 I was rushing to put back together - I just went out to the garage - I did the exact same thing!  I've got the narrower bushings in the upper rear mount with the same space you are seeing.   I must have used the rear bushings in the front when I didn't have any damped bushings I could lay my hands on - and had to face them off on the lathe to get the motor mount plates to align correctly  :Facepalm:  Think I'm going to need new rear mounts  :mad:

I've been grabbing random bits I've collected (and some lost) over the years - so no telling where my stuff came from!  I've also swapped around engines, cradles, etc I have no idea how any of this really looked coming from Yamaha.  Looks like 3 of the 4 front mounts are rubber damped and one is solid Loki g at partsfish?  Don't know where these shorter (narrower ?) bushings came from?  I can see how I goofed and grabbed the wrong stuff with a bunch of extras laying around - but the ones you used came from somewhere!  And the original thicker ones went somewhere too!

great white

Quote from: fj1289 on November 06, 2022, 08:26:19 PM
Funny thing is - my 89 I was rushing to put back together - I just went out to the garage - I did the exact same thing!  I've got the narrower bushings in the upper rear mount with the same space you are seeing.   I must have used the rear bushings in the front when I didn't have any damped bushings I could lay my hands on - and had to face them off on the lathe to get the motor mount plates to align correctly  :Facepalm:  Think I'm going to need new rear mounts  :mad:

I've been grabbing random bits I've collected (and some lost) over the years - so no telling where my stuff came from!  I've also swapped around engines, cradles, etc I have no idea how any of this really looked coming from Yamaha.  Looks like 3 of the 4 front mounts are rubber damped and one is solid Loki g at partsfish?  Don't know where these shorter (narrower ?) bushings came from?  I can see how I goofed and grabbed the wrong stuff with a bunch of extras laying around - but the ones you used came from somewhere!  And the original thicker ones went somewhere too!

Yep, fronts are 3 rubber and one solid. But the solid is seized into the boss and doesn't come out, so it can't be that one.

I'll have to pull everything out of the bins tomorrow and check. But I honestly can't think of another spot that ises bushings like these.

Watch me prove myself wrong tomorrow...

great white

Well, went through every bag and every bin.

the bushings in the frame are the only ones I have.

Also found a few more pics on the net that have a space at the frame/bushing/engine interface.

From what i can tell by looking at the rear upper mount it's purpose is to counter engine rotation, not to locate it side to side, so maybe the space is irrelevant.

Still, I don't understand what has changed from when it was factory assembled and now. Something must have moved, bent or warped somehow......

fj1289

Same set of engine cases as removed?   

I'm confused too - because the different pictures clearly show bushing that have different shoulder widths.  Like I said earlier, I can easily see how I got the wrong bushings - but not for your project! 

If it was riding weather still I'd of already turned up a new set of bushings or spacers for those bushings and not spend the time to ponder it! 

great white

Quote from: fj1289 on November 07, 2022, 08:53:26 AM
Same set of engine cases as removed?   

I'm confused too - because the different pictures clearly show bushing that have different shoulder widths.  Like I said earlier, I can easily see how I got the wrong bushings - but not for your project! 

If it was riding weather still I'd of already turned up a new set of bushings or spacers for those bushings and not spend the time to ponder it! 

yep, same engine. This bike is the only FJ parts I have lying around....