Welding frame with engine still in?

[Blue250X]

Well my subframe is cracking by the grab bar mounts so I'm gunna get it welded, Is there anything I need to do, any wires to disconnect so I dont fry my stator or anything? Thanks

[Pappy]

usually, you will want to disconnect the cdi box and the battery if the quad has one

[AtvMxRider]

Originally posted by Pappy
usually, you will want to disconnect the cdi box and the battery if the quad has one


Yes and keep your ground close to the spot you are welding.

[Blue250X]

Alright thanks guys. And If I leave it connected it will most likely be no good? haha

[Heybo]

Electricity will travel the path of least resistance. Put your ground next to your where you're welding and you shouldn't have to disconnect anything.

Think about it like water in a sink...... the drain is your ground and your cdi is laid up on the counter next to the sink.... you pour water in the sink and it goes down the drain. The water doesn't run up the side of the sink.

[Pappy]

Originally posted by Heybo
Electricity will travel the path of least resistance. Put your ground next to your where you're welding and you shouldn't have to disconnect anything.

Think about it like water in a sink...... the drain is your ground and your cdi is laid up on the counter next to the sink.... you pour water in the sink and it goes down the drain. The water doesn't run up the side of the sink.

ive seen several cdi's toasted due to not un hooking them. the electronics will not fair well IF a spike hits them. even changing a battery in a auto or truck with todays onboard computers requires attention to the small voltage spike delivered when re installing the battery during replacemnet. better safe then sorry!

[Heybo]

Originally posted by Pappy
ive seen several cdi's toasted due to not un hooking them. the electronics will not fair well IF a spike hits them. even changing a battery in a auto or truck with todays onboard computers requires attention to the small voltage spike delivered when re installing the battery during replacemnet. better safe then sorry!

Sorry Pappy, but I have to disagree with you. I took two years worth of electrical engineering when I was in college, and I've been a mechanic for over twenty years, eleven of which I've owned my own shop and the only way to damage a stator or cdi while welding is to place the ground in a place where the current travels through them. If any cdi's get toasted, that's because the ground was not placed right.

The ground lead needs to be place as close to the weld as possible with no wiring harness grounds in-between the weld and the grounding lead.

And the only way you might possibly damage a automotive computer when hooking up a battery is by hooking it up battery. There are too many failsafes in a automobile electrical system to damage it by just arcing the cable end.

But you are right in the philosophy of better safe than sorry if your not sure what your doing.

[NorCalRacer]

Originally posted by Heybo
Sorry Pappy, but I have to disagree with you. I took two years worth of electrical engineering when I was in college, and I've been a mechanic for over twenty years, eleven of which I've owned my own shop and the only way to damage a stator or cdi while welding is to place the ground in a place where the current travels through them. If any cdi's get toasted, that's because the ground was not placed right.

The ground lead needs to be place as close to the weld as possible with no wiring harness grounds in-between the weld and the grounding lead.

And the only way you might possibly damage a automotive computer when hooking up a battery is by hooking it up battery. There are too many failsafes in a automobile electrical system to damage it by just arcing the cable end.

But you are right in the philosophy of better safe than sorry if your not sure what your doing.

Alot of quads have diodes on the other end of the CDI's to get rid of excess voltage. I imagine if your welding ground went bad for a second you could send a spike to the diode frying the CDI. I've never seen it happen, but I imagine it is possible. Not knocking your experience, you obviously know what you are talking about, but old Murphy's Law comes to mind. I would definitely lean towards the safe side with CDI's being as expensive as they are.

[Pappy]

Originally posted by Heybo
Sorry Pappy, but I have to disagree with you. I took two years worth of electrical engineering when I was in college, and I've been a mechanic for over twenty years, eleven of which I've owned my own shop and the only way to damage a stator or cdi while welding is to place the ground in a place where the current travels through them. If any cdi's get toasted, that's because the ground was not placed right.

The ground lead needs to be place as close to the weld as possible with no wiring harness grounds in-between the weld and the grounding lead.

And the only way you might possibly damage a automotive computer when hooking up a battery is by hooking it up battery. There are too many failsafes in a automobile electrical system to damage it by just arcing the cable end.

But you are right in the philosophy of better safe than sorry if your not sure what your doing.

ive been schooled for the past 17 years in electrical systems(automotive, light and heavy truck, including the new 42 and 48 volt systems being tested for the new automotive line)(yes i have the fancy pieces of paper stating i am a certified automotive electrical nerd...lol) and have been welding on everything from bicycles to bulldozers since i was 15(grew up in my dads welding shop that he owned until he died) i have see men shocked from holding a cutting edge of a dozer 9 feet from the point of arc so please, dont tell me the current can not travel past the point of ground. ive seen airbags deployed while a battery was changed, and yes, computers in vehicles damaged by body shops welding on the car (that was GM's position after testing the computer)ive also seen jump starting batteries cause computer errors and failures. i deal with over 1200 shops on a daily basis and i am the go to man when there is an electrical issue for everyone from earls wrench emporium to mercedes benz. (sorry, figured you might like to know your not the only one with a smidge of training...lol)

in regards to what i think you meant (hooking a battery up backwards) this is not the only way to send a spike to the ecm. all it takes is a mere 5 volts to fry an ecm and other components in the system. hooking the ground up first and then the positive can send a 12 volt spike and if it reaches the ecm it will fry. a faulty engine ground can spike the system causing the ecm and other modules to receive spikes above what is design into their parameters and....poof.( we have documented a dump from a loose battery cable that sent a 80v transient spike through the system, ecm was toast along with other safety modules) a reostat gone bad in an altenator can send erratic voltage spikes through the system causing exceed levels at the ecm. (usually the altenator will fry and the car is down, but ive seen my fair share of folks that went weeks running a bad unit and jump starting to not trust people in respect to doing the right thing...haha) infact, right now i am helping invesigate (2) 2007 model vehicles that burned to the ground. first geusses are that voltage exceeded the system at some point and caused a failure which led to the fire. even mild voltage spikes in your home can damage a computer, so dont think striking an arc cant harm electronics! transient voltage spikes are unpredictable in the field and damage anything they hit. while manufactures build supressors into the electronics, they often fail and the component is hit.

im glad to see you can agree that a computer can be damaged while re connecting a battery, it is the same effect as striking an arc on a piece of metal... a voltage spike can wreak havoc on anything electrical, not always, but as i stated, better safe then sorry when YOU are the one responsible for knowing when its wise to take 2 seconds to make things safer and prevent possible issues.

[wilkin250r]

I know a thing or two about electronics. I've designed them. In fact, I would even go so far as to say I probably know more about electronics in general than anyone on this site.

Frying the CDI is unlikely, like Heybo said. The electrons have a fairly predictable path.

But if I was welding on my frame, I would disconnect the CDI. Goofy things can happen when you start energizing a frame and passing hundreds of amps through, even if you have a "path of least resistance".

Sure, the electrons have a path, but what about the voltage potentials in the microseconds before the arc flows electrons? You have to ionize the air, which will impart a voltage potential to the frame before the current flows, who knows what voltage potentials are flying around. And when current does flow, it doesn't happen instantaneously. Often it will oscillate above and below the steady-state level, causing a ringing that can impart more voltage potentials throughout the frame. They are called transient effects, because they are not steady-state, and I'm not going to trust my CDI to them all because I was too lazy to take thirty seconds to unplug it.

Your stator is safe, the it's just coils of wire that are pretty immune to transient effects, but the CDI is sensitive to tenths of a volt, it's easily damaged.

Problems are unlikely, but I'm no willing to take that chance to save a measly 30 seconds of work.

[Pappy]

Originally posted by wilkin250r


Frying the CDI is unlikely, like Heybo said. The electrons have a fairly predictable path.



but the CDI is sensitive to tenths of a volt, it's easily damaged.



which is it. you cant say its unlikely and then claim it is easily damaged...lol

[Heybo]

Didn't mean to cause a rucus...... this just gets in to a matter of opinion. Pappy sounds like you have similiar training and background to myself. I've also been trained to work on the new 42vdc systems that are going to be standard in cars very shortly. Personally, I've welded a hundreds of times on quads with no problems whatsoever. I guess I'm just more careful than most. If a person is unsure how to safely do it, then they should unplug the cdi, but I took the original post as asking if you have to unhook the electronics on the quad. In my opinion.... no.

[Pappy]

Originally posted by Heybo
Didn't mean to cause a rucus...... this just gets in to a matter of opinion. Pappy sounds like you have similiar training and background to myself. I've also been trained to work on the new 42vdc systems that are going to be standard in cars very shortly. Personally, I've welded a hundreds of times on quads with no problems whatsoever. I guess I'm just more careful than most. If a person is unsure how to safely do it, then they should unplug the cdi, but I took the original post as asking if you have to unhook the electronics on the quad. In my opinion.... no.

i tend to be very conservative online when it comes to telling someone something, and ive learned that if i reply i try to imagine the worse case scenario possible and the outcome. i to have welded many a quad with out touching it, but not on todays models where that one time could cost me decent money. not to mention the fact id see a thread in two days calling me a bum for giving someone info that cost them money as well...lol

have fun with the new systems, so far they are causing all kind of issues and the techs are not trained to handle them...

[Blue250X]

Originally posted by Pappy
not to mention the fact id see a thread in two days calling me a bum for giving someone info that cost them money as well...lol


haha. Don't worry Pappy, I'm going to unplug my CDI so you won't be hearing that from me.

[wilkin250r]

Originally posted by Pappy
which is it. you cant say its unlikely and then claim it is easily damaged...lol

Why not? Just because something is easy doesn't mean it's likely. It's easy to french-kiss a fish, but that doesn't mean people are likely to do it. :blah:



By "easily damaged", I meant in comparison to the stator. A voltage spike probably won't harm a stator, but it would harm a CDI.