The CB1100 Community Forum

I just installed the sw motech bars. Very impressive fit and finish.....a little confusion on torque specs on front down tube bolts, but found old post with correct info

Congrats on that Cqrlm. I hope you NEVER find out if they work or not.

First of all you are all better off with the crashbars, of course, but i did find some info about the damage on the engine mounts.
this is from a cb1300 on" zam's channel " on youtube if you want to have a look yourself, the engine is strikingly similar to our cb1100 and mounts to a similar frame in the same way, and i have no idea why it broke off since he did not mention it but some time later i saw him mount frame sliders on the same bike, they were however plastic by the looks of it, here are some pictures i took of the video;







and the video; https://www.youtube.com/watch?v=R2jSb_mxypc

Not to disagree here with anyone's choice but wanted to show the result of an accident.

Well-spotted, Max.
I think these CB engine mounts are disgraceful for thesereasons...
1. They are placed too far to the outer edges of the crankcase where they are very vulnerable to being struck
2. They are grossly insubstantial. If I recall, my '72 CB750 mounts were bigger affairs that went right across the engine from one side to the other, with one big long bolt securing the two sides.
3. This is from a world-leading manufacturer, so you wouldn't expect these sort of errors.

As a result of 2017EX, Houtman and other's observations on crashbars (my preferred protection) I have switched my intentions to buy from Hepco&Becker to the SWMotech offering - very similar bars but with two main differences - an additional metal strip between engine mount and bar mount on SWM, that allows a little flexibility in an accident and reduces "shock", and a different attitude to the mounting bolt - rigid and inflexible on H&B or "sacrificial" in nature on SWM.

Here are my own broken engine mount pics:

Very compelling example. However, accident environments/situations are harsh. I suppose it is a matter of degrees of damage control.

Can you weld that broken mount ?

(06-21-2019, 10:43 AM)Houtman_imp Wrote: [ -> ]Can you weld that broken mount ?

Yes, I could, John.
The best course would be to...
1. Take the engine out of the frame and replace the lower engine block. Or
2. Next would be an engine-out, strip-down alloy-weld repair. Or
3. Then an in situ alloy-weld repair, and finally
4. A JBWeld repair.
Removing the engine is out of the question - it would ALL have to be done at a dealer and the cost would be prohibitive! It ain't gonna happen, 'cos I can't do it myself.
I spoke to my welder (who coincidentally owns an old Honda Four!) and whilst he was prepared to look at the job and maybe have a go, he was unsure about doing it in situ because of the heat generated by the weld
. At that time I was going to take the 'bike for him to have a look, on my way bringing the 'bike home. My 'trailer plan' failed when the hitch broke so the 'bike was brought straight home here and the welder hasn't looked at it yet.
I decided to at least TRY the JBWeld - I'll be keeping a VERY close eye on it. If the product is as good as the reports, it'll be fine. If it's not, I will have to deal with it then.
The crack itself is UNDER the weight-supporting part of the bracket. It is totally supported on either side by big penny washers, clamped and torqued up, then clamped to the frame. The weight is downwards, onto the unbroken part and I can only see it breaking again if it gets an upward whack like last time. Of course, it may fail through vibration, heat, whatever but all reports suggest that will not be the case. No weight is being taken by the weld - just holding the loose underneath part UP onto the solid top part.
It is what it is and although not ideal, I'm keeping my fingers crossed. (And toes, and arms, and eyes!).

5. make the 5mm vertical drain hole in the mount bigger and closer to the front and tightly wind something strong like layers of piano wire or stainless locking wire used for racing around the whole boss ( like a hose clamp ) after the jbweld has cured, the more the stronger, the form is already there and paint over it.

Then if you don't like it it's easily removed with side cutters and if it is giving way it may do so gradually in the future.
If skillfully done this can be quite strong with high tensile steel wire ( and cheap ).

Thanks Max.
I had actually considered a U-shaped metal "brace", much along the lines you've suggested, but I really don't think it will be necessary. The joint, cramped-up by the bolt and compressed between the large washers, is very well supported and braced - there will be zero movement and very little, if any, stress. I'm quietly confident it will be a successful repair.

Speaking of the sw motech bars, the instructions suck. I had to go back through old posts on here to find the torque specs for the 2 stock engine mount bolts on down tubes being reused for the bars(36 ft/lbs). The supplied swm bolts(one on each side) are torqued at 28 ft lbs. I think/ hope I did it correctly.