welding on motorbikes

[chunkolini]

Right, in the thread about stuck niples I mentioned that I have a couple of rounded off bolts on the rear brake of my BMW.
Pedrobedro reccomended welding a nut on the end of the bolts and removing them thattaway. I will have a look at it in a day or so, I have work to get out of the way first.

Welding on a bike? this thing is loaded with little black boxes and computery things. How do I stop frying the electrics? is it as simple as disconnecting the battery?

Cheers all, Chunko'.

 

[ttoks]

if your bike runs a CDI ignition, you'll need to remove that, as well as dissconect the battery, the best way is to remove all electronics before welding as you really have no idea what mgiht be sensitive to high current, however i can tell you from experiance that welding with the CDI on the bike may cost you a few hundred bucks.

 

[Pete.]

Disconnect the battery and unplug the ECU, that's what I do and my bike has a lot more electronics on it than most.

 

[shenion]

I would disconnect the batt and connect the leads together.

 

[Pete.]

I would disconnect the batt and connect the leads together.

I wouldn't do that. Bikes typically have an earth bond from frame to engine and then to battery negative, sometimes via a 'Y' lead and often minor earths from the loom to the frame/engine too. If you're welding on the frame with the earth clamp on the engine and there's a poor connection anywhere you might re-direct welding current up the earth bond and straight into the loom.

 

[peterd51]

Hi,

surely you should never weld on any vehicle body/frame with the clamp on the engine or vice versa?

It'd be the same as welding the exhaust with the earth lead on the bodywork. Asking for trouble, I reckon...

Regards
Peter

 

[chunkolini]

Have managed to find space to have a look at it tomorrow.
For starters I will use heat and violence , specifically Pedrobedro's method involving a copper rod jammed in the end of the offending bolt, loads of heat then a measure of violence. Then more research before application of the Mig welder.

Chunko'.

 

[Pete.]

Hi,

surely you should never weld on any vehicle body/frame with the clamp on the engine or vice versa?

It'd be the same as welding the exhaust with the earth lead on the bodywork. Asking for trouble, I reckon...

Regards
Peter

I guess I should have put 'for example'. My point is the earth strap connects structural parts for the purpose of conducting electricity and if the connection between these parts was deemed to be perfect there would never be any need for one. It stands to reason that there must be a possibility of welding current being transmitted down the strap.

 

[sharkey]

I just disconnect stuff until there's an open circuit between the electrics and the frame: on the XLV, that's the battery -ve cable and the loom to chassis lug, plus a couple of assorted sensors (oil pressure, neutral switch, CDI sensors) ... no problems after building up a good fat bit of weld on a flogged out sidestand plate. The only tricky bit is finding somewhere for the earth clamp.

 

[pedrobedro]

I welded some luggage hangers on a Diversion a couple of weeks ago and all I did was disconnect the battery earth. It's done a trip to France and back since then and covered nearly 1,000 miles no problem. I cleaned the frame and connected the clamp next to where I was welding.

 

[chunkolini]

Forgot to report back on this one.
Tried loads of heat a copper soldering iron on a stand, heated with oxy/acetylene, no joy.

Wary of welding onto it , so we drilled the hads off the bolts, and use them as locating studs to centre the disc as the wheel is held on by 4 gurt big bolts.
Everything is fine and ABS sensor is behaving itself.

Chunko'.