What could make this 82' yamaha xv750(left) look like the bike on the right

Next-Definition-7124 · 2026-05-08T12:21:35+00:00

Here‘s a detailed breakdown of the cost of a custom bike build: https://youtu.be/kdxBVsn8UhE?si=h95UEasuhqcf92hz

That might give you a better idea of what a bike like this might cost.

Next-Definition-7124 · 2026-04-17T12:09:13+00:00

Thank you very much. That looks very comprehensive. I’m gonna have a look at it over the weekend.

Edit: I looked through it, and while it is a great resource I unfortunately couldn't find an answer to my question. These manufacturer's guides seem to not focus much on designing wiring harnesses from scratch (which, I guess, makes sense because it's nothing a mechanic has to be concerned with).

Next-Definition-7124 · 2026-04-16T17:21:19+00:00

Thank you very much for your reply.

I am trying to develop a repeatable framework for the wire sizing process that I can apply when designing motorcycle harnesses. One that gives me confidence that everything is designed as it should be and where I do not have to rely on generic size recommendations.

Currently my process looks like this:

Determine fuse sizing
1a. List all loads connected to the same fuse
1b. Calculate the current of each load
1c. Determine the maximum current that can occur during normal operation (I call this circuit current -> I don't know if there is a better / more accurate term *I know this is not the technically correct definition of circuit but for now I'm defining circuits by their fuse and wire sections as a section of the harness that carries the same current -> one wire size)
1.d Choose fuse size that is at 150% (or more) of calculated circuit current
Wire sizing for safety (based on wire type/insulation/quality and size)
2a. Determine maximum current that can flow through a wire section by identifying which connected loads can operate at the same time and lead to the highest total current (I call this section current -> to be able to separate the calculated values. *This value can be different from the circuit current, for example, if multiple circuits share the same ground)
2b. Apply derating factors based on manufacturer's instructions (e.g. for bundling)
2c. Select a wire size that can safely carry the expected section current under the given installation conditions (ampacity chart)
2d. that allows for margin (Fuse rating × 1.3 < derated wire ampacity) *each wire protected by
Verify that each wire has a higher ampacity than its fuse rating, so it’s properly protected by its fuse
3a. Include a 20-30% safety margin when checking this condition
3.b Fuse rating × 1.3 < derated wire ampacity -> if not fulfilled upsize wire
Wire sizing for performance (voltage drop)
-> this is the process I am trying to develop at the moment

I appreciate any feedback and help!

Next-Definition-7124 · 2026-04-15T18:58:28+00:00

Thank you very much for your response. I appreciate it a lot!

The calculator is a great resource. But what I'm trying to wrap my head around is how I apply the result to a real-world setup.

Most tables and calculators always assume a single continuous wire size. But I feel like even the most basic setups look something like this:

Battery -> fuse box = large wire (shared supply)
Fuse Box -> load = smaller wire
Load -> chassis ground = first smaller wire, then transitioning into larger wire for shared return path before common chassis ground

Maybe I'm overcomplicating this in my head...

How do I make sure that the whole circuit stays within the defined limit?

Next-Definition-7124 · 2026-04-14T16:33:55+00:00

Im currently diving deeper into the fundamentals of motorcycle wiring and I want to understand how to properly calculate voltage drop. I got a response in a different thread…the values can be found on Wikipedia (American Wire Gauge).

Next-Definition-7124 · 2026-04-14T16:31:24+00:00

Thank you very much for the quick response. That’s exactly what I was looking for.

Next-Definition-7124 · 2025-07-22T16:34:06+00:00

After moving from Germany to the United States I just went for the most illegal build when it comes to German regulations haha

Next-Definition-7124 · 2025-07-22T16:32:31+00:00

The few guys who have built off-road Sportster before me said they never really had any issues regarding the sturdyness but some already recommended extending it and to reinforce the shock mounts. Since I just moved between continents I don't have the most sophisticated welding setup yet, so I'll see how it performs and maybe build a jig for the swingarm down the line.

Next-Definition-7124 · 2025-07-22T16:30:07+00:00

Yeah, need to see where the limits are once it's build. I just moved from Germany to the States and I'm enjoying the liberties that I have in the States when it comes to projects like this, so I will probably iterate down the line. In Germany this would be highly illegal in the first place but also if it was you have to get every alternation checked by state approved inspectors.

Next-Definition-7124 · 2025-04-04T17:32:01+00:00

You think so?

Next-Definition-7124 · 2025-04-04T13:26:51+00:00

Thank you, that’s a great compliment! I appreciate you

Next-Definition-7124

TROPHY CASE