Jaydela180
XS650 Addict
Ever seen this? given i shaved them up a bit and only using left side.
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Broke top motor mount.
- Thread starter Jaydela180
- Start date
That's a first for me. Was the top bolt (the one that bolts the 3 pieces together) loose when you discovered this?
You should be using both left and right...................Yamaha knows best about these things.
1st time 4 me 2.
Both sides were broken on my '74. Some of the bolts were loose too. Would like to know which happened first, loose bolts or broken bracket?
CORRECTION...AFTER LOOKING......Only my right side was broken, same place, some of my other mounts were loose too, I'm sure about the mid-rear being loose, probably adding to the stress.
Scott
CORRECTION...AFTER LOOKING......Only my right side was broken, same place, some of my other mounts were loose too, I'm sure about the mid-rear being loose, probably adding to the stress.
Scott
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I would suspect that too. I would think that all of the mounts being tight, and staying tight, would be more important than the bulk of the mounts.
Scott
The more that I look at the design of those top brackets, it's as if they were designed to break away before cracking the engine bosses. The thin areas are in the "stress" areas.
Scott
Scott
Not surprising that it broke. By eliminated one half of the brackets, its was down to 50% strength, and then by shaving, its down to
40% to 45%. Its possible that Yamaha did design a "weak" area into the brackets, which makes it even more important to use both brackets.
40% to 45%. Its possible that Yamaha did design a "weak" area into the brackets, which makes it even more important to use both brackets.
I made these top mounts, a copy of other bobber brackets. Sloppy tack welds, good welds now.
Jaydela180
XS650 Addict
Always believed it was necessary to have a top motor mount....that is why it wasnt completely deleted. now i understand that both are needed.
Yes bolt was loose.
Yes bolt was loose.
Orion61
XS650 Addict
Well, I guess that answered the question for the guy when he asked if he could run without the top brackets a week ago or so!
One of mine was cracked like that when I got my bike. I just welded it back up. I've since replaced it with an unbroken spare. I checked all the engine mounts when I got the bike. Not just a couple, but ALL were loose. The self locking nuts used on the motor mount bolts don't hold as well after they've been on and off a few times. I add regular split ring lock washers to them.
My early 70-74 service manuals make no mention of any kind of tightening sequence for the upper mount jumble. I've just tightened mine gradually, in a sequence that makes sense to me. Does a 'tightening sequence' exist for the later models?
Not in the SJ or E manuals. Just the torque values for the different points.
weaselbeak
XS650 Junkie
My son had an XS650 chop hardtail that ran with no top mounts for twenty years. We refurbished it a couple years ago and I made mounts just for the hell of it.
member3480
RICH
I have ran many without top mount and never had problem. But if you want one I do have parts for one.
All these bikes have been on streets for over 6 years no top mount
Just PM me your address and I will send you some spares
All these bikes have been on streets for over 6 years no top mount
Just PM me your address and I will send you some spares
