BROKE MOTOR MOUNT

[Luke D.]

Good day everyone,  I was cleaning my bike last night and I think I have a broken motor mount.  If you are sitting on it its the front right hand side.  (I will upload a picture later) right now I have a couple questions, is it possible (safe) to weld the frame with everything on it? (motor, electrical, cables)  I had a bicycle a few years ago that cracked the frame and the welder tacked it so I could get home but found out when he welded it the cable housing all melted so I could not do anything. Are there certain things I can take off to help not do that? Gas tank, unhook the battery?  Or do I have to disassemble the bike entirely?  I am planning a big trip in about three months so I figure I should get this done sooner rather than later(and I don't want to miss much riding in the mean time.)  Thank you all for your help and have a great day.

[Bob_Roller]

I've wondered about this myself .
I have a broken side stand mount and have not gotten around to having it repaired .
I would think if you are going to have the break arc welded, all of the bikes electrical grounds should be disconnected and insulated from touching anything .

[Tony Smith]

For stick welding, depending on where you are welding (more on this below) you are mostly safe if you disconnect the battery. BUT out of an abundance of caution I would remove the Ignition ICU and unplug the tachometer - in theory both should be safe for frame welding once the battery is disconnected, but out of an abundance of caution I would physically disconnect any devices containing semiconductors. The alternator/diode board should be OK, but again it would take only a couple of minutes to effect complete electrical isolation.

The OP mentioned an unexpected outcome of cables being fused on his bicycle. In a similar vein there are two circumstances you need to be wary of on a motorcycle - Do not allow the welder to ground out his welder on any part of the handlebars, forks etc, nor any part of the swing arm. Both these areas contain lots of nice clean bare metal and are immediately attractive to a welder looking for somewhere to hook up his or her welding earth connection. To do so runs the risk of welding up the bearings (or at least damaging them so as to make riding an unpleasant experience) or worse. 

An acquaintance of mine some years back was destroying (he called it caffeinating) a Yamaha XS750 and found that he was in need of some bracketry to relocate things like the battery and ignition boxes. He thought that the nice shiny triple clamps would make an excellent earth connection for his stick welder - it did too, but the electrical path went through the head stem bearings and welded them up.  That would have been a cheap lesson (nearly all the electrics were in a nearby storage box), but after doing the first job he moved to the rear of the bike and thought that the shock mount on the driveshaft side was likewise a handy-dandy earth point - that one cost him a shock absorber and a final drive.

[Luke D.]

Thank you Bob_roller and Tony Smith for your inputs.  I promised pictures and that may help a little.  Hopefully they all load. I did notice there is a cable that runs right along the motor and frame in that spot. I don't think I would put the grounding clamp THAT far up on the bike.

[skippyc]

I have had welding on my bikes and the secret is to keep the earth as close to the weld as possible, look for potential burning and shield for splatter.
I didn't remove any wires. Good Luck. 

[Tony Smith]

Ah....The Romanian guest worker had an off day, a lovely bead of weld, sadly not where it needed to be. That is an easy repair but do yourself a favour and pay someone to do it with a MIG or TIG, not a stick welder, much less mess to clean up and less chance of damaging the engine. Leave the bolt in whilst all that happens or you will never get it to line up again.

[mrclubike]

It looks like to get to the motor side of the boss the motor will have to come out
I personally would dissemble the bike or at least remove the engine after the boss is tacked in place
The old welds may also locate it just fine with the bolt resting thru it  if you take the motor out before welding
I am glad to see it looks like a misplaced weld at the factory instead of a failure caused by fatigue 

I would rather MIG or TIG it than stick weld it

It looks like your VIN tag is going to take a fair amount of heat so I would try to protect that as much as possible

[Luke D.]

Do you guys think the 36 year old factory warranty is still good?  Is this something any (reputable) welding shop can do?  Mrclubike you say the old welds can be used to locate where the mount should be but Tony_smith is saying its not where it should be, where should it be? Would it be wise to lift the motor a tick to get the mount to where it should be and so the bolt will be nice and lined up? Kind of based of what Mrclubuke says would it be okay to weld the outside with the motor in and then take the motor out to get at the inner weld?  Is it possible to JUST take the motor out? Thank you all again for your help.  Have a great day.

[Tony Smith]

Do you guys think the 36 year old factory warranty is still good?  Is this something any (reputable) welding shop can do?  Mrclubike you say the old welds can be used to locate where the mount should be but Tony_smith is saying its not where it should be, where should it be? Would it be wise to lift the motor a tick to get the mount to where it should be and so the bolt will be nice and lined up? Kind of based of what Mrclubuke says would it be okay to weld the outside with the motor in and then take the motor out to get at the inner weld?  Is it possible to JUST take the motor out? Thank you all again for your help.  Have a great day.

Actually MrClubBike and I are saying the same thing, from different perspectives.

We both agree that the initial re-welding should be done with the engine and bolt in place.

I said it was a lovely bead of weld - just int he wrong place because it didn't actually "bond" the two pieces of metal - but I agree what is there is still useful in that it will provide a means of locating the mount whilst the welder does the initial re-welding.

MrClubBike says that after the initial tack weld the engine has to come out to finish the welding - he is correct, however I am intensely lazy and if I got a good strong, well included weld on the outside edge I'd bee tempted to not bother pulling the engine to do the inside edge. I would however watch it carefully and if it showed signs of cracking the weld again, then I would do the job properly.

Your welder will advise you, but you will probably be putting a jack under the bolt to lift it firmly into place prior to welding, you will need to close that gap prior to striking an arc.

[skippyc]

I got a mate to mig weld my BSA as its to easy to burn through the frame with the stick welder and it does a much better job. you can fill the weld much better with a mig.

[Semper Gumby]

Hey Skippy.  Which BSA doyouhave?   

[skippyc]

Hey Skippy.  Which BSA doyouhave?   

1972 B50t