Wiring through frame

I am seeking info about running some of the harness through the frame to clean up the look.
I'm hoping a member would post their experience doing this.

Which locations were opened up for passage, also techniques in doing so.
Positives, negatives of this. (the only neg. I think of is access ability, but I would make any connections in the open)

Hullsfire said:

I am seeking info about running some of the harness through the frame to clean up the look.
I'm hoping a member would post their experience doing this.

Which locations were opened up for passage, also techniques in doing so.
Positives, negatives of this. (the only neg. I think of is access ability, but I would make any connections in the open)

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A couple of things come to mind.
Structural integrity of the frame. I assume any material you remove makes it weaker. I am not an engineer so this is an assumption.
As far as cleaning it up, most of the wiring can be pretty well hidden under the tank and wherever it comes out of the frame will expose it to whatever component to which you are attaching.
Any hole may create a friction point (and a rust point) that could rub through the wires, and potentially create a direct short to the battery.


Someone did post how they ran the rear light wires through the hoop and regarding integrity, that seemed safe.

I would not feel comfortable cutting into the main tubes.

Custom Harley -Davidson people know the most about this , Norton peoples not too much ,vibration factor very high.

I've done it both building choppers and industrial settings. Methods must include holes big enough to fish wires and pins through. Deburring and grommetting are key. What is your skill set? Done much wiring? Harness building? Will you use plugs? Or solder connect each device permanent style?

I feel this is something within my grasp to do if it makes sense to attempt.

5. Wiring runs up the main frame tube

The chassis;I decided to modify the frame by running the wiring in the main tube (see photo 5.).  The spine of the frame was opened at the back end near the rear mudguard, so you could see right up the frame tube. A hole at the top was made so that the wiring could come out. Holes were also made at the rear for the tail light wiring, and brake light. The tail light was replaced with the earlier unit with the reflectors on the sides as I thought this was a lot more shapely than the later square one. I made two holes in the rear loop to hide the wiring for the rear light, I certainly didn’t want cable ties on it."

This was taken from the article below:

http://www.stotfoldengineers.co.uk/stot ... r-of-love/

About half way down a decent photo of the wiring entering the main frame tube.

Rear loop was the only spot I felt needed blind wired. It exits thru an enlarged hole in the taillight bracket. I grommetted both to prevent the obvious.

I would strongly recommend against it. The bending moments and stresses in the main top tube are high, particularly if you have front disk brakes and use fairly havy braking. Look back through the old posts about frame failures. The top tube wasn't near as strong as we thought at N-V, and there were many fatigue failures just aft of the head-stock bracing piece. Any hole drilled in the tube wall will introduce a stress raiser, particularly if it's anywhere other than on the horizontal center of the cross section. Holes top or bottom of the tube would be the worst.

The main reason our pre-production testing at Marston Road didn't reveal the weakness in the original top tube was that the wimpy 2LS Italian brake couldn't generate enough bending moment into the frame.

To any of you with an AJS Stormer that doesn't have the ovoid top tube, you have the same risk of a fatigue failure, but on the top of the tube rather than the bottom. We did have failures on the AJS moto-cross team bikes.

I'll do a post in the AJS Stormer thread to alert people.

I can see the wisdom of routing away from the cluttering outside frame. The spine and tube are about match book thick metal but of decent dia. not to be very weakended by openings at its ends near middle of the tube mating to stem or butt plate. If the holes made pretty close to the welded seams there will not be any flexure to matter. Holes made between gussetts are also not much a strenght or fatique issue. if really worried like me putting a 3/4" OD hole in top of spine for oil filler, was to silver soder in a fitting that actually backs up the area against fatigue. All the Commando fractured frames, after they added the under spine tube have broken at the rear tube junction area above the rear iso.

Well, two strong arguments. Very succinct. Thank you.

One with factory credentials. The other with frequent knowledge on here.

I have emailed the articles author. Although the article is three years old. Hopefully stress on the frame was something he considered.
I really like the idea.

There's examples of OIF with big holes for fittings that did not break apart so far. A couple of 1/2" holes or one 3/4" between the spine and brace tube would land in a null zone of loads and if pensive could weld or rough nick up surfaces good an JBW cold weld a bent washer over the hole and butted to the stem for a stronger area than untouched surrounds. This might allow thick blunt enough edge entry not to need grommet. My personal recoil to doing this has to do with the extra clutter shifted somewhere else to allow all the reuseable connections to service or replace stuff. That's fairly rare enough might just solder and wrap to make wires long enough can disconnect at the item it feeds, bulbs and switches. Rear loop hole should be underneath not side walls and up close to frame as its weak spot is ~6" further out. Non issue for hole near tail light.
So what ya got in mind ahead of the spine? In stringing leads inside do note that the straight out tube the middle tubes weld to spine goes completely through the spine which narrows the space above and below it. There will be a light patina of rust inside raw surfaces so might consider a pickling or painting of spine from exposure to you know what.

That's great info, Hobot.

Do you mean to spray the inside of the tube?

I haven't decided what I would do at the top end. I eliminated a few wires not being used so a 3/4" hole would be sufficient.

The top tube wasn't near as strong as we thought at N-V, and there were many fatigue failures just aft of the head-stock bracing piece.

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Frankdamp, I believe the hole would go between the steering tube and before the weld for the head-stock piece. Would that smaller triangle above the head steady be less affected?

"Rear loop hole should be underneath not side walls and up close to frame as its weak spot is ~6" further out".

I'd rather take my chances with where I put the hole then move closer to the shock mount??!! Or put it on the underside, which defeats the purpose of blind wiring....

I agree with a point from each of you:

up close to frame as its weak spot is ~6" further out".

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. - closer to the weld I would prefer

Or put it on the underside, which defeats the purpose of blind wiring....

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. - for aesthetics yes, but also along the horizontal axis

In structural work, when a penetration is made through a beam, doubler-plates are installed to replace equivalent metal to that removed by the penetration, and thus keeping the same moment of inertia (second moment of area, actually) as the original beam. This retains its original strength.

I am with frankdamp here: I wouldn't go drilling willy-nilly into the spine of the frame. But, if you are going to, at least add doublers to strengthen the area at the holes. Better yet, find a local structural engineer with good FEA program and pay him a few hundred bucks to see what the effects on stress would be. After all, it's you that will be scooting down the road on your face if the frame breaks due to a fatigue failure brought on by high, localized cyclical stresses.

Just my 2c worth ....

I think you could clean up the front end nicely by routing the two big grey electrical wires that reside by zip strips alongside both handlebar ends by drilling entry and exit holes in the bars in front of the clutch and break lever mounts, it seems there is very little stress on the handlebars that such small holes would impact

1up3down said:

I think you could clean up the front end nicely by routing the two big grey electrical wires that reside by zip strips alongside both handlebar ends by drilling entry and exit holes in the bars in front of the clutch and break lever mounts, it seems there is very little stress on the handlebars that such small holes would impact

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That's how my Yamaha is, it is a pain to change out the bars thou.

Lots of cycles ran-run wire through bars, got a used old Honda set like that on SV650 after goating got em. Snoop around or search google images to see they make a slot for wire to pass through not a round hole which tends to bind more. You are not going to weaken bars to matter as will bend as easy on crashes with or w/o the holes. Next thing to do is mold the frame joints smoothly blended like a woman curves.

I've found that it's more a problem with the bulky bullet connectors than the wiring itself. You could go a long way in cleaning up the harness by replacing them with some of the modern gasketed connectors. DigiKey has them, rubberized heat shrink tubing, and other nice stuff that almost makes messing with the wiring enjoyable. (If the wiring harness is original then the bullet connections could actually be broken under the plastic sleeves.)

http://www.digikey.com/