Weld-on Hardtail Advice

[jdwertz]

Starting tearing into a hardtail project I purchased a few years ago. 1972 xs650 with a random assortment of parts.

Seller told me it was a TC Bros weld on hardtail. Aside from the poor welds, does this look correct? I have a hunch that these tubes should be straighter.

 

[mrtwowheel]

That looks right for that part of the frame, I just welded one on, nothing straight about the rails there. Also, your exhaust brackets are cut off, that would make those tubes seem even more crooked when they really aren't. Is your left side bottom rail comparable to the right side?

Scott

 

[Brew]

the only way you'll know is if you throw the engine in so....

 

[jdwertz]

Engine fits for sure, it was already in the frame mounted the bottom and rear mounts. I took it out to fix the poor welding that was done.

Thanks for the tip, I will put it back in and to verify that it lines up with all the motor mounts.

Both rails look comparable. I will have to take some more pictures later today.

 

[hard_y_rd]

73 and earlier frames have a lower backbone. The P.O likely hiked the hard tail up so the rails would meet it. I heated the upper rails and bent them down so they would be able to be welded to the backbone. It should be ok if everything is straight from side to side. Chuck the motor in and measure from an area on the motor like the sparkp plug tips to the rear axle. Just to confirm the measurements are square.

 

[DIRTY DOG]

looks about like every other TCB hard tail out there MY 72 looked the same way also the 72 didn't have the exhaust mouts on the frame

 

[mrtwowheel]

That's the compromise in the design, so that the back bone tubes look straight and the other hard tail tubes are parallel to the ground.

Scott

 

[mrtwowheel]

Yeah, your frame is different than mine. I found the best place to measure diagonals was from the exhaust mounts to the forward part of the axel slot. Is that bung under your hand "factory"? If so, and you have one on the other side, that would be the best place to measure to. Hooking a string on the front of the front sprocket, stretching the string to the axel, move the string till it barely touches the rear of the front sprocket, string should be in line with rear sprocket. Diagonals and the string on the sprockets were the best confirmation for me. I was also working with a "recycled" hard tail, but fitting the cut-off hard tail to my frame. The guy before me was off by 1/8" on one side, that made a difference of 1/4" at the axle, diagonals and the string verified I was straight again.

Scott

 

[jdwertz]

Thanks guys, very helpful information. I will measure the frame this week. Then I will be fixing all the PO's work.

Ground down some welds to check penetration and was extremely disappointed. This joint was mostly Bondo.

 

[DIRTY DOG]

clean it out with a wire wheel and have the welds redone

 

[jdwertz]

I am stripping the whole frame and will Tig up the joints properly. As long as the measurements pan out.