KymcoForum.com
General => Technical | How To => Topic started by: EvilTessmacher on June 21, 2018, 01:38:41 PM
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A rather odd question here (do I ever ask any other kind? ::) )
Are there any engineering specs available for these bikes? The reason I ask is, I'm trying to find out what a specific part is made of. The rear carrier rack (the one that passengers hold on to) that wraps around the back of the seat. I'd like to know what it's made of, as I'd like to tap a 7/64" hole in it to mount a bracket. I think that it's made out of cast aluminium, but it could be cast zinc, or some other metal, and that will have an effect on the fastener I choose.
(https://thumb.ibb.co/nPjRh8/rack_01.png) (https://ibb.co/nPjRh8)
Anyone have any idea what that thing is made of?
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Displace water to measure the volume. Then weigh it to calculate the density. Maybe?
Or see what temperature it melts.
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Really?
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The first one is a real suggestion. If it's light for its volume, it's probably aluminum. Zinc and steel are more similar, but zinc is a touch lighter.
Just put it in a bath tub with enough water to cover it. Mark the water line (non-permanently), and take it out. Count how many gallons of water it takes to get back up to the line, and you have your volume.
http://www.coolmagnetman.com/magconda.htm (http://www.coolmagnetman.com/magconda.htm)
The second suggestion would work too (zinc has a very low melting point), but I'm assuming you don't want to melt it. That one was just a joke.
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My "opinion" is the DT300I "luggage rack" is some very light-weight fiber substance that is very stong. If I were to drill and tap that stuff or aluminum thread inserts would be in the plan without fail.
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I really didn't see the "real" in the first one, as I'm not a technical/engineering type, and weights, displacement, and all that kind of thing never occurred to me. I don't have that kind of test equipment available to me. The second wasn't really all that funny, since I was asking a serious question, and didn't expect any frivolousness. I'm kind of a serious person, and humour almost always has to be clearly indicated as such. My sense of humour was surgically excised years ago following a rather unfortunate combine/harvester accident. In any case, to do that test would require removal (which is something I am trying to avoid) and destructive testing, and the part is a couple hundred dollars. Not a viable option, IMHO.
I did try to attach a magnet to it, but it didn't stick. So, I thought of some other non-magnetic metal.
WRT the rack for the DT300i, is it the same as the X400i? I know on my old Honda it was an aluminium alloy. I'd really rather not have to take it off if I don't have to. Could you explain in greater detail how you would add an insert? I thought of some sort of backing plate, but I didn't want to have to drill all the way through it, lest it weaken. A 7/64" hole that is less than 1/2" deep shouldn't compromise it much.
This is starting to become a rather interesting exercise. I may have to cobble together a set of photos to explain in greater detail, although that goes against my practice in asking certain types of questions. I've found that when one provides too much information, that people who answer usually don't think outside the box, and go with stock, preconcieved, uninspired answers that don't solve the problem.
This is getting interesting.
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I think I'm missing the joke.
Is hypophthalamus's suggestion of using commonly available supplies and equipment to calculate density of the rail to determine its composition not an answer from someone who thinks outside the box?
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I think I'm missing the joke.
Is hypophthalamus's suggestion of using commonly available supplies and equipment to calculate density of the rail to determine its composition not an answer from someone who thinks outside the box?
I think I'm missing your sarcasm. It isn't a viable answer because it requires removal and mathematical calculations unnecessary to answer the actual question that was asked, vis, "what is it made of?" It would be "thinking outside the box" to say "I don't know" rather than to give a response that neither answers the question nor is responsive to the question asked.
Please don't try to make me the bad guy for asking a specific question, and expecting a legitimately specific answer to the specific question that was asked.
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No, no sarcasm intended. Just genuinely confused and wondering if I'm missing some humour. Just seemed like he gave you a method to figure out for yourself, but you dismissed it with reasoning that didn't make sense to me.
Personally, I'd take it to a machinist and ask what the rail would be made of.
Please carry on. :)
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Again, my opinion as both a practical technician and a practical routine engineer (ships and aircraft)(OK, scoots, too!), Hypo is a good guy and is right on with an over-engineered suggestion. I would also tell him to pack sand, I ain'T sinkin' this thing inna bathtub! (Humor intended!) So, you want a nearly 1/8" hole not quite 1/2" deep threaded? To answer your first question, there are no specs on materials that I know of available to us. It is like pulling hen's teeth to get ANY answers to our normal questions from either the dealers or Kymco USA. Second, threads in anything other than steel are likely to pull out and a thread insert like Heli-coil (lotsa other brands today for the same thing)is the superior solution ESPECIALLY if this stuff is like fiberglass or other non-metallic structural material. The neat thing is you want to drill an original hole in something rather than enlarging an existing hole. Enlarging an existing hole with the odd-sized twist drills supplied by the coiled thread repair kit is TOUGH because the drill wants to grab a huge bite right off! So, OK, you get to drill an easy hole then tap it for anchoring a braket, right? You will have to finish tapping the hole with a bottoming tap. This type of tap will be available for any standard SAE or metric thread.
Now the question: Could you use a deeper or a through hole?
What are you gonna mount with this bracket?
How heavy is this mounted thing?
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Again, my opinion as both a practical technician and a practical routine engineer (ships and aircraft)(OK, scoots, too!), Hypo is a good guy and is right on with an over-engineered suggestion.
It was so far outside what I was expecting that I didn't see any of that.
Ooops.
I would also tell him to pack sand, I ain'T sinkin' this thing inna bathtub! (Humor intended!)
You go ahead. I'll watch. Popcorn anyone?
So, you want a nearly 1/8" hole not quite 1/2" deep threaded? To answer your first question, there are no specs on materials that I know of available to us. It is like pulling hen's teeth to get ANY answers to our normal questions from either the dealers or Kymco USA.
This I know, which is why I asked here. I figured someone might have an idea, and it would be easier to get an understandable answer here, than from Kymco.
Second, threads in anything other than steel are likely to pull out and a thread insert like Heli-coil (lotsa other brands today for the same thing)is the superior solution ESPECIALLY if this stuff is like fiberglass or other non-metallic structural material.
My intention is to use a self-tapping machine screw. Drill a pilot hole as big as the shank of the screw, and let the threads do the biting. With a little Loctite for good measure.
The neat thing is you want to drill an original hole in something rather than enlarging an existing hole. Enlarging an existing hole with the odd-sized twist drills supplied by the coiled thread repair kit is TOUGH because the drill wants to grab a huge bite right off! So, OK, you get to drill an easy hole then tap it for anchoring a bracket, right?
Right.
Here's what the bracket looks like:
(https://thumb.ibb.co/i82W28/20160811_161221.jpg) (https://ibb.co/i82W28)
Where the bolt in the center is located, is where the self-tapping, self threading screw will go.
You will have to finish tapping the hole with a bottoming tap. This type of tap will be available for any standard SAE or metric thread.
Now the question: Could you use a deeper or a through hole?
What are you gonna mount with this bracket?
How heavy is this mounted thing?
I don't know about a through-hole. I think that would weaken the grab rail far more than a little bitty hole. I also don't think I could do a through-hole there, without going all the way through to where the seat is. So probably not.
This is what's being mounted:
(https://thumb.ibb.co/mS2s9o/light_01.png) (https://ibb.co/mS2s9o)
It's dimensions are 2.26" W x 1.2" H x 0.875" D
It can't weigh more than a couple of ounces. I say this, because it hasn't arrived from Fleabay yet.
My thought was to get one of those self-tapping sheet-metal screws and just attach the very light, thin aluminium bracket (with a thin neoprene foam "gasket" between) straight to the grab-rail. With a little Loctite (or maybe epoxy) for good measure.
In this location:
(https://thumb.ibb.co/jLufUo/rear3.png) (https://ibb.co/jLufUo)
It won't ever bear any weight, it isn't in a location where anyone can inadvertently grab it, and it really doesn't seem like it's going to cause any difficulties being where and what it is. I had something similar on my Honda, except it was attached to the Tupperware, because there was a convenient place to do it.
So, I need a little-bitty self-tapping, self-threading screw to attach that thin aluminium bracket (less than 3mm thick) to the as-yet undetermined metal of the grab rail in an out-of-the-way location.
Then, mount the light to the bracket, and wire it into the brake light, so that it's only on when I have the brakes applied.
Furthermore, I have one of those little modules to wire in where it strobes 5 times, slow-blinks 5 times, and then stays on.
It gets attention even in the daylight.
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Drill through; use washer and nut on other side and either loctite or nylon lock washer as backing. Ensure bracket is robust enough to hold what item you are fastening to it (at top speed as well). Also check out how the bar is fastened to the bike, (you might be surprised or disappointed by what you find.
I removed the seat pan from my Like 200 and 3 of 4 of the mounting screws were cross threaded.
Good luck!
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Evil, thanks for the pictures! I over-engineered with the thread coil. Your method of direct threading should work fine, in my opinion.
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Fishcutter: I'd rather not through-drill anything, as that might well weaken the integrity of the grab rail. The bracket weighs about a third as much as the light it will be holding.
Karl: "Whew!!" 8)
I most definitely am no engineer. In fact, I despise math, having learned since high school that X isn't lost, and neither is N. I had a teacher then (Mrs. Busch, I hated her) who would write the problem on the board, write the answer below it, say to the class "everybody got that?" and then erase it. Whenever I'd ask what was all the stuff in the middle between the answer and the problem, she'd tell me "you ought to know that by now" and I eventually ended up in detention for pestering her for explanations... Letters and numbers don't mix.
My major problem now, will be finding screws which are appropriate in size for this operation. I think I'm going to have to go to a local nut-bolt-screw warehouse, and beg for some help...
But, I'm almost ready to do all the new safety lighting! A pair of 1/2" amber eagle eyes up front, a matching red pair in the rear, the two flexible COB DRLs, my pair of bullet aux brake lights, and my nifty little bracket-mounted high-strobe brake light.
Soon, Diana will be lit up like a christmas tree!!
Mod Report and Pix, of course.
Thanks for all the input gang!
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LOOK UP FASTENAL there may be one in your area,.
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LOOK UP FASTENAL there may be one in your area,.
I've never heard of them. Thanks! Another source is always welcome!
We have a place where I live, not unlike Grainger, called "Stanford Co." that does nothing but nuts, screws, bolts, and other specialized fasteners. Years ago, when I was working for a local engineering company as a draftsman, one of our engineers was retiring, so we clubbed up and bought a huge nut and bolt for him as a parting gift. I swear, that thing must have weighed 6 pounds or so. The nut alone was almost 4" in diameter and almost 2" thick. The dang thing was huge. If memory serves, it cost us about $30 or so.
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I've never heard of them. Thanks! Another source is always welcome!
We have a place where I live, not unlike Grainger, called "Stanford Co." that does nothing but nuts, screws, bolts, and other specialized fasteners. Years ago, when I was working for a local engineering company as a draftsman, one of our engineers was retiring, so we clubbed up and bought a huge nut and bolt for him as a parting gift. I swear, that thing must have weighed 6 pounds or so. The nut alone was almost 4" in diameter and almost 2" thick. The dang thing was huge. If memory serves, it cost us about $30 or so.
Another cool online place would be McMaster https://www.mcmaster.com (https://www.mcmaster.com)
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Update:
I stopped by Stanford today, told the guy what I was looking to do, showed him one of the brackets off the Honda, showed him the new light (it arrived yesterday) and he went over to a bin and pulled out three stainless steel self-drilling screws. Dropped them in my hand, and told me to come back and show him how the bracket fit. I told him I hadn't made it yet, and he pulled four little strips of aluminum out of a drawer (turned out to be 0.040" - just the right size!) about an inch wide and six inches long, and asked me if these would work to make the brackets with? I told him they would, and he said "ride safe young man" and shuffled off to the back of the store.
Anyone remember Fraggle Rock? The old guy named Doc, in the workshop? This fellow looked just like him.
I have all the pieces in place. I'm off all next week from work, as we're all closed for the week for the holiday, and I now have to try to remember how I made the first bracket...
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Having been a mechanic all my working life, I would do it. The weight of your lite is miniscule compared to the strength of the hand rail. Through hole or not, will not make much difference either. I like through holes, you won't need a bottoming tap.
BTW, don't buy cheap taps (such as Fastenal).
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Having been a mechanic all my working life, I would do it. The weight of your lite is miniscule compared to the strength of the hand rail. Through hole or not, will not make much difference either. I like through holes, you won't need a bottoming tap.
BTW, don't buy cheap taps (such as Fastenal).
Thanks for the advice! It's always good to hear things from people who have significant experience!!
Having said that, I absolutely have zero experience working with a "tap", not even knowing what one was until it was mentioned here. I had to go look them up to see what it was. This also means that I have no idea how to use one, no experience using one, and that means I will absolutely screw up whatever it is I am attempting to do with it. Hence the holes. Which I am doing tomorrow.
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A little late to the party but....2013 300GTi rack is made of #5 plastic..Polypropylene