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K100-forum.com » Technical, repair and troubleshooting » Frame, fairing and wheels » Frame welding: What to disconnect?

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1Back to top Go down   Frame welding: What to disconnect? Empty Frame welding: What to disconnect? Sat Nov 01, 2014 2:16 pm

fearghal

fearghal
active member
active member
hey there forum, i've done some research and read that its advised to disconnect the ECU and BOTH battery terminals before doing any welding on the frame of these bikes. 

a couple of questions - is that FOR SURE all you need to disconnect? to be extra sure i don't fry something is there anything else i should be disconnecting? 

also, in terms of unplugging the ECU - where is the best place to do that? 

thanks!!

    

92KK 84WW Olaf

avatar
Life time member
Life time member
You have a unit under the seat with a multipin, another up at the headstock also multipin and also a unit for ABS, in rear cowl or also under seat. A wise man told me take the 3 of them off the bike to be sure. As well as disconnect both battery terminals. Not hard to get them off. Gas tank off gets you at the headstock and there are slots at the screws so you loosen them and it will slide backwards between all the wires.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 48,061 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 61,190 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

indian036

indian036
Life time member
Life time member
I'd also be disconnecting all wires from the alternator to ensure diodes aren't blown.

With all the electronics, there is a fair chance that no damage would result even if not disconnected, but with the cost and inconvenience of replacements, I wouldn't be taking the chance!

Cheers,

Bill


__________________________________________________
1985 K100RT  VIN 0028991  My original Very Happy ROB the Red Old Bike   (Historic rego)
1985 K100RT  VIN 0029036  BOB the Blue Old Bike  (Historic rego)
1990 K100LT  VIN 0190452  Work in progress
1984 K100RT  VIN 0023022  Work needing lots of progress
1986 K100RT  VIN 0090542  Work needing lots and lots of progress
1993 K1100LT  VIN 0183046  Work in progress
1993 K75S  VIN 0213045  Tom the Triple (now on Historic rego too.)
    

Holister

Holister
Life time member
Life time member
Definitely the alternator, ECU and ICU located under tank behind head stock. Be careful you don't have any wiring in the way. With a welding helmet on its difficult to be accurate if you're a novice welder like me and using an arc welder. I think I may have fried my blinker relay this way recently. In future I'll be disconnecting any connector I can find including the instruments.
https://www.k100-forum.com/t8698-welding-fairing-brackets


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808		 Frame welding: What to disconnect? Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
Twenty years ago a mate of mine from interstate was passing through on a ride and stopped for a visit. The centre stand bracket on his RT broke, rendering the stand useless. I located a friend with a welder and over he went to the bloke's place. They disconnected nothing, sparks flew, and the stand was made secure.

Time to go....no start.

The next day when the local dealer opened they quite luckily obtained a secondhand ECU and replaced it at the welder's expense - he was quite apologetic. The bike ran for another ten years or more on the replacement ECU. You pays your money and you takes your chances.


__________________________________________________
Patience is something you admire in the driver behind you and scorn in the one ahead.
~Mac McCleary
1977 R75/7-100, '93 K11/K12 Big Block, '95 R100 Mystic, '96 K1100RS, '98 K1200RS, '06 K1200R & '09 K1300GT. Projects: 1993 & '96 K1100RS, & 1st '98 K1200RS.
The Mystic, Big Block, 2nd K1200RS, K12R & K13 are running & ridable.
    

indian036

indian036
Life time member
Life time member
indian036 wrote:
With all the electronics, there is a fair chance that no damage would result even if not disconnected, but with the cost and inconvenience of replacements, I wouldn't be taking the chance!

Two Wheels Better wrote:I located a friend with a welder and over he went to the bloke's place. They disconnected nothing, sparks flew, and the stand was made secure.

Time to go....no start.

The next day when the local dealer opened they quite luckily obtained a secondhand ECU. You pays your money and you takes your chances.

In support of my initial statement, it would seem that the ignition unit, alternator, instruments suffered no damage.

In support of my final statement, the fact that the ECU blew means not taking the chance is a good thing.

There are times when my oxy-acetylene welder saves time and trouble.  Very Happy

Cheers,

Bill


__________________________________________________
1985 K100RT  VIN 0028991  My original Very Happy ROB the Red Old Bike   (Historic rego)
1985 K100RT  VIN 0029036  BOB the Blue Old Bike  (Historic rego)
1990 K100LT  VIN 0190452  Work in progress
1984 K100RT  VIN 0023022  Work needing lots of progress
1986 K100RT  VIN 0090542  Work needing lots and lots of progress
1993 K1100LT  VIN 0183046  Work in progress
1993 K75S  VIN 0213045  Tom the Triple (now on Historic rego too.)
    

fearghal

fearghal
active member
active member
Thanks everyone for the info - super helpful!

    

Holister

Holister
Life time member
Life time member
Results can be catastrophic, expensive and cause a lot of inconvenience. So just to consolidate everyones contribution into a list of things to disconnect before welding...


  1. Both battery terminals
  2. Alternator plug.
    Behind gearbox R/H side. Remove coolant reservoir.
  3. Fuel Injection Unit - aka ECU.
    Under tool tray under seat. Release on R/H side pull out from L/H side. Plug swings out.
  4. Ignition Control Unit (ICU) if fitted.
    Under tank behind head stock.
  5. ABS if fitted. R/H side.


Copy and paste and repost if you have something to add or change.
Cheers


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808		 Frame welding: What to disconnect? Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

Inge K.

Inge K.
VIP
VIP
Kaptain Holister wrote:

  1. Both battery terminals
  2. Alternator plug.
    Behind gearbox R/H side. Remove coolant reservoir.
  3. Fuel Injection Unit - aka ECU.
    Under tool tray under seat. Release on R/H side pull out from L/H side. Plug swings out.
  4. Ignition Control Unit (ICU) if fitted.
    Under tank behind head stock.
  5. ABS if fitted. R/H side.


Copy and paste and repost if you have something to add or change.
Cheers

Other parts with electronics inside, and could be expensive enough if you don't have them at hand.

      6.  Instruments (both connectors).
      7.  Flasher relay. (relay box, rear LHS).
      8.  Fan relay. (relay box, middle RHS, 2V only).
      9.  BMU relay. (relay box, middle LHS).


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

Be made

Be made
Life time member
Life time member
Hall transmitter too methinks. Pretty sensitive they are

    

floyd

floyd
Life time member
Life time member
I just disconnected the battery.

No damage at all. 

Not condoning this behaviour, just reporting it.


__________________________________________________
K100 with lots of K1100 bits - mongrel of a thing...
    

charlie99

charlie99
VIP
VIP
I figure all you need to do is to remove the battery positive

if all things are equal....the only reference that can be made to all the electronics is the ground

the ground voltage may go up ...but the important factor is that the difference to any other electronic component is  maintained through the ground  reference ...


as all things electrical have both a positive and a negative ,....remove the positive references and all should be good

just a opinion  that makes sense


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

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