HOW TO: replace shock mount

[Bjorn]

I have to replace this and thought i might share my proces. Probably not the most common repair out there. And not for rookies, but hey, this info might come in handy. Could even be someone visiting the forum through searching this topic. I don't know how this got bend, maybe the previous owner dropped it? I've owned the bike for >10 years so it's not new.

Why this repair:
I noticed my RHS top shock mount was bend, this put a lot of sideway force on the shock, something I don't want. Since it's winter here and I got the tools, I decided to just replace the whole thing.
My first plan was just to drill it from one side, bend it back and reweld it. However I noticed the threads were below the lower wear limit. Making me replace the whole mount.

Shock out of alignment.

Out by 2,2 Deg metric.

Step 1: remove the old shock mount
I bought a hole saw with a inner diameter that would just fit over the protruding stub. This worked out great, just got slow and use some oil.

This was the point where I just wanted to bend it and reweld. However the worn down threads made me decide to just make a new one.

Removing the back side was not as clean since the hole saw with drill was to big to fit between the frame rails. I just used an angle grinder.

Continues below

 

[Bjorn]

Step 2: Make a new top shock mount
Owning a lathe makes this step much easier. Other wise you might need to ask a machine shop. I got all the dimensions with a drawing, might post that at the end.

I made the new one out of S355 steel, its and average construction steel with decent strength, easy to machine and good weldability. I don't think Yamaha used anything high strength for this XS frame anyways.

I made the big OD a bit longer so I can stick this out a few mm more, Yamaha engineers and manufacturing engineers did not really put a lot of effort in the welding jigs, looking at the swingarm shock mount being out by a hair. Protruding the top shock mount a bit aligns the both.

I used the same aluminium tube to make it level and in line with the other mount.

Step 3: welding
Not my prettiest welding job ever, but it will be sufficient. Used TIG, removing most of the powder coat first. (Big disadvantage of the powder coating, doing mods later is a PITA)

Done! New shock mount with fresh M10x1,25mm threads.

 

[Its been a long time]

Great job. Very neat and tidy.

 

[Charles13]

Wow that’s beautiful much nicer than stock

 

[cra-z1]

Welds look good to me. Nice job.

 

[Mailman]

Very pretty work, nice job!

 

[magoo66]

Nicely done.

 

[Wingedwheel]

Thanks for the lesson in a job done correctly! Very nice..

 

[Bjorn]

The dimensions in case anyone ever needs to make this: