Topic: Can I weld this part of the frame? 1978 CB750F

[86FJNJ]

I am cleaning up some of the welds on my 1978 CB750F frame. This area on the two front down tubes looks to be crimped and possibly plug welded (the three circular spots on the upper tube) but there is a visible edge where the upper tubes slides over the lower tube.

Is there any reason I could not run a weld bead at this joint to clean up the look of the frame so instead of a raw edge there is a weld bead? I'm guessing maybe they just didn't weld it due to manufacturing costs. I can't imagine that frame area needs to flex but seeing what the group thinks.

[MRieck]

I'm no expert in the field of welding but I don't see why not....it's not going to move. Just be aware that tubing isn't that thick.

[crashmaster]

I don't see a problem as long as you stagger the welds, and don't weld it all at once. Let it cool some to prevent any possible warping

[jonda500]

If you are doing it to make it stronger don't do it as it will actually weaken it slightly! If you are doing it for the look then go ahead, but consider silver soldering it instead?
John

[newday777]

"the three circular spots on the upper tube"
Those dots are electrical Spot welds....by a robot welder.

[86FJNJ]

"the three circular spots on the upper tube"
Those dots are electrical Spot welds....by a robot welder.

They had robotic welders in the 70's?

[86FJNJ]

If you are doing it to make it stronger don't do it as it will actually weaken it slightly! If you are doing it for the look then go ahead, but consider silver soldering it instead?
John

My intention is to do it for looks to clean up the look of the frame a bit, I could keep the amperage really low so it just barely smooths it out as to not weaken it much at all. I actually stumbled on a post in this group from over 10 years ago where a guy welded them along with some other modifications. Apparently the factory was sleeving these in this way to make engine fitment at the time of assemble easier and to reduce labor cost of full welding, at least that's what the internet is saying.

[newday777]

"the three circular spots on the upper tube"
Those dots are electrical Spot welds....by a robot welder.

They had robotic welders in the 70's?

Yes

[Stev-o]

"the three circular spots on the upper tube"
Those dots are electrical Spot welds....by a robot welder.

They had robotic welders in the 70's?

FYI from AI:

Robotic and automated welding technologies were in use in the 1970s, and Honda was a pioneer in adopting these methods to achieve the high-volume, high-quality manufacturing required for machines like the Honda CB750.

[HondaMan]

Yeah, the robot welders could hold the clamps that forced those "dimples" you see in the top collars. As the current flowed and the melt started the robot monitored the current to see it reach a certain high level that indicated the outer steel had melted and the inner steel was melting, then it held for {x} amount of time. Honda invented that whole thing, circa 1975, to prevent the extensive hand-welding on bikes like the 750.