How secure front isolastic bolt while removing nut?

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Jun 14, 2007
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There's gotta be a trick....the inner timing cover blocks the bolt head enough that you can't use a socket or box wrench (ring spanner?) - and an open wrench at the angle required looks like a sure bet to strip the bolt head.... how do you folks tackle this?

Thanks - BrianK
I use a socket on the drive side of the bolt. it will either loosen slightly or rotate enough to get an open ended spanner onto the nut at the timing end. You can then loosen and remove the bolt and nut.
Thanks Dave. I have a nut on the drive side, bolt head on the timing - but the problem is the inner timing cover blocks the bolt head such that I can't get a clear shot at it, even with an open wrench - pretty sure it would slip and strip if I tried to hold it with that.

I'm gonna see if I can wedge a quarter in there or something. Probably could get the nut OFF with an impact wrench, but that will still leave me with the issue of securing the bolt head so I can torque the nut back on.....
Brian, I assumed you were talking about the upper bolt that holds the front isolastic mount to the engine cases, where the clearance is very tight indeed, but I now see that you are talking about the centre bolt that attaches the isolastic mount to the frame. I have just popped down to my workshop where I have 3 750 Commandos in various stages of assembly and see what you mean about the limited space, however my original statement about holding one end is still valid. With the friction inherent in such a long bolt, I always find that you don't have to hold it extremely tight to tighten the nut on the other end as it compresses and an open ended spanner even at an angle should be adequate. If you come at it backwards from inside the frame rail you can get the spanner almost square with the bolt head.
The timing cover castings vary from model to model. I can get a 5/8" AF Garringtons ring spanner on the Mk111 850 but not on the MkV 750.

Both are accessible with a 3/8" drive Gedore 5/8"AF socket.

3/8" drive sockets are the thing to have for many jobs on the Commando.
Thanks 79. Unfortunately, I can't get ANY socket on the bolt head on my 850 - the inner timing cover blocks it entirely. My box wrench won't fit either - possibly if I ground down the "ring," but I don't want to do that to a good wrench, and at least at present don't have a spare one I can experiment on. If worse comes to worst, I may buy a cheapo one and try. Thanks - Brian
Brian, I have adjusted Isos away from home with my touring toolkit and if the nut is not galled on the threads, as others have suggested, an open-ender will provide enough resistance to stop the bolt turning.

I assume you do have the correct reduced hex bolt ? Which model engine is it ?
You were right, 79, I was able to get an open end on it by coming down vertically from the top. Job done.

Thanks much - Brian
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