Tricks to finding Top Dead Center of frame tubing?
I need to weld a bung to the left and right side of a motorcycle frame backbone to mount the subframe. If I can find TDC of the frame tube I can measure from there to find the left and right center lines.
Does anyone have any tricks on how to find TDC or the left and right centerline?
Here's the frame in question. The mounting location is above the carb in the straight section.
Google "center finder". You'll get lots of hits but this one looked like the right solution. A bit pricey but you might be able to whip one up yourself. Just make certain the frame is perfectly vertical.
Ive doe something similar with paper.
Caliper the tube so you know the actual diameter.
Calculate the circumference.
Layout three marks on a strip of paper and wrap around the tube.
You still have to have a reference for one of the marks, but the two on the sides will be directly in line with each other.
If you can find the top center, you'd be good and don't need any special tools.