welding precautions

[Ronkom]

I'm looking at mounting a Hepco-Becker tail trunk on my '17 V7III. It appears that I'm going to have to shorten the stock luggage rack to properly mount the H-B. All this means cutting 3 1/2" off the rear of the rack, then welding a piece of 3/4" flat stock across the cut ends of the 4 tubes to tie them back together for strength and to seal them.
Obviously, it would be best to disassemble the rear of the bike to remove the rack & do the work. But, I'm wondering if the bike's electronics can be isolated to safely weld w/the rack on the bike.
Opinions?
Ron   

[dsrdave]

Disconnect the battery and unplug the ecm at a minimum. Obviously still best to remove the part. 
My 2cents

[pete mcgee]

What Dave said.
Plus have the welding earth as close as possible to the area being welded.
Personally Id take it off the bike.

[Adk.IBO]

When I had both my Norge and Roadster trailer hitches fabricated I insisted nothing be welded on the bike, wasn’t going to chance it. I either clamped or drilled and bolted joints together, removed, then welded... Extra precautions saved any electronic issues, well worth it to me.

[John A]

What Dave and Pete said is all I've ever done but the newest Guzzi was an '02 and I don't know how much the electrics have changed

[Adk.IBO]

I know my 2017 Roadster has 2 computers plus an ABS module that sends signals via CanBus. Electricity will travel to ground through the easiest path. Eliminate human error everywhere you can... such as a text message right before pulling the trigger on a new mig welder you’re not used to yet or an old one that has paint chips on the ground clamp that compromises the connection. 5 millionths of one amp will kill you if it crosses your heart, what it takes to fry an ECM I don’t know...I do know I’d take the rack off...

[Chuck in Indiana]

I had the comm boards on the cnc mill and computer fry when communicating while I was TIG welding. 25 feet away. (!!)  I'd get the computer and battery off the bike if I *had* to weld on it.

[Ronkom]

Thanks guys, Answers were what I expected.  I'll take the rack off the bike....and move the bikes w/computers away from the welder when I run it.
Ron

[redhawk47]

My recommendation: buy a Hepco-Becker rack.It will save you the fiddle and futts trying the make your old rack work, and the top case will be firmly attached, and easy to remove if you want it off.
Dan

[Lannis]

My recommendation: buy a Hepco-Becker rack.It will save you the fiddle and futts trying the make your old rack work, and the top case will be firmly attached, and easy to remove if you want it off.
Dan

WHAT?  BUY a ready made one when a home-made one is already available?   That's in violation of one of the True Blue Guzzi Requirements!!      

Put a No Guzzi Content on that post!   

Lannis

[Chuck in Indiana]

WHAT?  BUY a ready made one when a home-made one is already available?   That's in violation of one of the True Blue Guzzi Requirements!!      

Put a No Guzzi Content on that post!   

Lannis

That's true, Lannis. You should see the hoops I'm jumping through trying to adapt a windshield to the G5 that was never meant for it. It was FREE, though.. <Guzzi content.>

[Ronkom]

Grin!! I bought the HB mounting rack, designed to bolt to an existing rack on the bike.   The problem is that the tail trunk latches to the rack on the bottom. If I bolted it to the V7III stock rack far enough back to be able to mount/remove the trunk it would look ridiculous. By shortening the stock rack 3 1/2", the HB trunk fits up where it should, so the back rest pad is usable for a passenger & it looks right.
Ron

[nobleswood]

That's true, Lannis. You should see the hoops I'm jumping through trying to adapt a windshield to the G5 that was never meant for it. It was FREE, though.. <Guzzi content.>

Relieved to hear it ! Where's the red suspenders emoji..

[Ronkom]

I got the rack off the bike....and what do I see but a small "givi" sticker that was hidden when the rack was on the bike. I pulled up internet pictures of '17 V7III Specials and didn't see any w/a rack like the one I'm dealing with. So, the thing is an aftermarket Givi that was installed by the dealer along with the Givi bag mounts.  Ah well, when I'm done w/it I'll be able to mount my 40L HB tail trunk. The Givi hard bags that came on the bike are the small ones...30L? I wondered about how the bigger tail trunk would look, but Just setting it on the rack & stepping back for a look....it doesn't look bad at all. I have a pair of larger Givi bags, but the upswept exhaust pipes prevent using them w/the mounting brackets where they are. I looked at what would be necessary to raise the brackets......then told myself Nah, I'll just make do w/the small bags.
Again, thanks for the responses
Ron

[Sasquatch Jim]

 I would put it together and gas weld small tack points.  Then take it off and electric weld it.

[Rick in WNY]

Son-of-a-welder here... and yes, I know you already pulled it off, that is by far the safest bet.

As mentioned, gas welding, aka, oxy-acetylene, could be used to tack it with no electrical repercussions, but that's about the only on-machine welding I'd accept.

Vehicle confusers are delicate, and welding machines are... hazardous at times.

Of the electrical welding types, stick is the least likely to fry a brain box. Then MIG or gasless MIG, and finally, the worst offender, TIG, because of the HF start.

Best to minimize your chances of frying one of our vehicle mounted silicon overlords - remove the part from the vehicle. However, with TIG, this may not be enough. The TIG welder needs to have good ground connection to the part being welded, but also, the welder itself needs to be well grounded on the power side.  This is because when the high frequency start is used, the TIG wires are pulsing with a signal much like a radio broadcast signal, ie, the lead wire acts like an antenna. If the machine is not properly grounded there is enough RF leakage that this can induce a current in a nearby piece of metal.  A bench, a chair, or a vehicle. Or in Chucks' case, a CNC mill and computer. I'd hazard a guess that the cable was just a standard network cable and not a shielded one... or not properly grounded. Think about it, 25 feet away is nothing for a radio signal, and that's why it fried.

[Chuck in Indiana]

Or in Chucks' case, a CNC mill and computer. I'd hazard a guess that the cable was just a standard network cable and not a shielded one... or not properly grounded. Think about it, 25 feet away is nothing for a radio signal, and that's why it fried.

Ahh, yep. I had a shielded comm cable shortly thereafter, and used that for years. I've joined the 20th century, now though..  and have a new operating system on the cnc that has almost unlimited memory that can store big programs so I don't have to DNC. (communicating directly with the computer) Potential problem solved. Just the same, I don't  TIG weld with the CNC or the computer running.
Over kill? Maybe, but it's *really* expensive when the magic smoke leaves the CNC control..

[Zoom Zoom]

Son-of-a-welder here... and yes, I know you already pulled it off, that is by far the safest bet.

As mentioned, gas welding, aka, oxy-acetylene, could be used to tack it with no electrical repercussions, but that's about the only on-machine welding I'd accept.

Vehicle confusers are delicate, and welding machines are... hazardous at times.

Of the electrical welding types, stick is the least likely to fry a brain box. Then MIG or gasless MIG, and finally, the worst offender, TIG, because of the HF start.

Best to minimize your chances of frying one of our vehicle mounted silicon overlords - remove the part from the vehicle. However, with TIG, this may not be enough. The TIG welder needs to have good ground connection to the part being welded, but also, the welder itself needs to be well grounded on the power side.  This is because when the high frequency start is used, the TIG wires are pulsing with a signal much like a radio broadcast signal, ie, the lead wire acts like an antenna. If the machine is not properly grounded there is enough RF leakage that this can induce a current in a nearby piece of metal.  A bench, a chair, or a vehicle. Or in Chucks' case, a CNC mill and computer. I'd hazard a guess that the cable was just a standard network cable and not a shielded one... or not properly grounded. Think about it, 25 feet away is nothing for a radio signal, and that's why it fried.

Good info from someone that is in the know.


Could Ron wrap the bike in tin foil? I mean it works for keeping the aliens from reading our brain waves.

Just kidding...

John Henry

[Chuck in Indiana]

^^^^^ Are you sure, ZZ?

[roadventure]

Obviously, it would be best to disassemble the rear of the bike to remove the rack & do the work.

You stated the best thing to do in your original question.  Seems like a "no-brainer" since you already know that removing the rack for welding is the best way to go.

[Lannis]

You stated the best thing to do in your original question.  Seems like a "no-brainer" since you already know that removing the rack for welding is the best way to go.

Well, sometimes you just like to hear it from someone else.   For me, I can get to staring at something all by myself in the shop for too long and start doubting my own judgment ....

That's what we're here for.

Lannis

[SIR REAL ED]

Well, sometimes you just like to hear it from someone else.   For me, I can get to staring at something all by myself in the shop for too long and start doubting my own judgment ....

That's what we're here for.

Lannis

Very well stated Lannis.  One should never be shy when asking for advice or guidance.  In effect, you are complementing the other person by saying "I value your opinion." or "I think you may know more than me."
 
Lots of times one is 90-95% sure of how to proceed, but that little bit of doubt often leads to a much better understanding or knowledge base after others are consulted.  This thread is a great example.  I already knew welding anything on a vehicle is risky, but now I know a lot more about why.

TIG's acting like miniature EMP WMD's is excellent information to know!!!!

On the other hand, as "they" say "The man who can tell good advice from bad advice doesn't need advice!"

or "Where everyone thinks alike, no one thinks very much!"

[Rick in WNY]

Between having a welder for a father and a very close friend who is a certified HAM radio nut... I guess you could say I've been educated by people who know about these things. I will say that while the welding stuff makes sense to me, radio is just a bit to the right of magic in my book. There are people who understand that stuff way better than I do, and I'm glad they do, because while it's not quite reading tea leaves or chicken guts, it's pretty dang close as far as I'm concerned.

Thankfully, I don't have to understand how it works to understand that it works... kinda like computers and fuel injection.

Glad I could pass along some information, and that it was even useful!

Rick

[lucian]

Whats all this have to do with wedding precautions? 

[SIR REAL ED]

Between having a welder for a father and a very close friend who is a certified HAM radio nut... I guess you could say I've been educated by people who know about these things. I will say that while the welding stuff makes sense to me, radio is just a bit to the right of magic in my book. There are people who understand that stuff way better than I do, and I'm glad they do, because while it's not quite reading tea leaves or chicken guts, it's pretty dang close as far as I'm concerned.

Thankfully, I don't have to understand how it works to understand that it works... kinda like computers and fuel injection.

Glad I could pass along some information, and that it was even useful!

Rick

I appreciate it.  I've worked with weldors and welding engineers a lot over the last few years.  Much, much more to it than just melting metal.  Seems foolish not to pick the brains of those who have knowledge one does not have when the chance presents itself.

Prior to reading your post, I would not have hesitated to fire up a TIG unit with a fuel injected bike 10 feet away.  Now I won't.

thanks in advance.

[Rough Edge racing]

 Not necessarily bikes, but newer vehicles often have multiple ECM's.....Do you remove them all ? Do you know where they all are ?  I do welding on vehicles but it's  older stuff using MIG, I put the ground as close as possible and no problems...I use TIG but not on running vehicles...

[Rick in WNY]

Well Rough, as the people who build the TIG machines will tell you, it can be done. In my experience, it's often less important what the welding machine is than how it was set up and being run. A properly installed, properly grounded TIG machine with the ground clamp placed as close as possible to the weld location is much less likely to cause issues than one that was installed haphazardly and being run with the ground at one end of the vehicle and the torch at the other.

That said, removing the item to be welded is the safest bet. I know, that's not always possible, so then do the best you can to minimize the effects. Pull the battery cable is one thing you can do, ground clamp as close to the weld as you can manage is another. The only one I know to be completely safe is to remove the part... everything else has risk.