MK3 Restomod

lcrken

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Thanks for the kind words guys. I'm really enjoying this one. And I do seem to be making a lot of custom parts, but I'm also trying to keep the Commando look as much as possible. I'm even trying to find a good way to fit the original front fender and have it look right.

Ken
 

lcrken

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Finally got the cush drive finished. It was interesting learning how to machine the polyurethane rubber for the cush part! I was told the best way was to freeze it in dry ice or liquid nitrogen, but I found a way to do it at room temperature that worked pretty well. These are all the bits.



And this is a shot of the back of the cush drive and the rear wheel.



And finally, installed on the bike.



And now the punch line. I made a mistake in the drawing that put the sprocket .250" (the width of the sprocket) too far out. There's not enough material to fix it, so I'm now in the process of making it again. This will by my third iteration. Hopefully I'll get it right this time :?

Also working on modifying the seat pan to clear the wider rear shock mounts, and making brackets for the Lucas headlight. Slow progress is better than no progress.

Ken
 

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gortnipper

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grandpaul said:
Well, that incorrect one will sure make nice wall art.

Make a clock out of it and sell it.
 

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lcrken

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Now there are a couple of ideas I wouldn't have thought of. I usually just throw failed designs in the scrap bin, hoping to make use of part of them for something else. Maybe I should start hanging them from the rafters in the shop as humility reminders.

Anyway, I'm almost done with the (hopefully) corrected piece. Lots of time spent standing at the lathe and mill for this sort of thing. If I were doing more than one of these, I'd go to my buddy's CNC shop and pay him to do them. Trouble is, if I'd done that, it would still have come out wrong. I did a nice CAD drawing to help me get all the holes in the right places, etc., etc., but the dimensions in the drawings were wrong. A perfect example of GIGO.

Ken
 
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lcrken said:
....... Maybe I should start hanging them from the rafters in the shop as humility reminders...... Ken
Shoot, seems to me you don't need to bother with that, you're building a one of a kind, truly fabulous bike there. The only people who never make any mistakes are the people who never do anything, right? :)
 

lcrken

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cjandme said:
lcrken said:
....... Maybe I should start hanging them from the rafters in the shop as humility reminders...... Ken
Shoot, seems to me you don't need to bother with that, you're building a one of a kind, truly fabulous bike there. The only people who never make any mistakes are the people who never do anything, right? :)

Besides that, I'd probably run out of hanging room pretty fast. I find that for the more intricate fabrications (cush drives, caliper hangers, fork yokes, etc.) it usually takes at least two tries to get them right. I'm starting to be more careful about doing a careful CAD drawing first, and that does seem to help. But I still make a lot of parts based on quick paper sketches in the shop, a picture in my head, and maybe a cardboard pattern. Being able to do 3-D CAD would help even more, but that's a skill I haven't developed (yet :lol: ).

Ken
 

grandpaul

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lcrken said:
... I'm starting to be more careful about doing a careful CAD drawing first, and that does seem to help. But I still make a lot of parts based on quick paper sketches in the shop, a picture in my head, and maybe a cardboard pattern. Being able to do 3-D CAD would help even more, but that's a skill I haven't developed (yet).
I have a custom knifemaker friend who allows me free use of his lathe, mills, belt grinders, etc. He asked me last year to show him some AutoCad, which I did (rudimentary stuff). Together, we produced his first tactical folding knife pattern which has become quite popular (single blade linerlock flipper, sells for approx $1,000). Fast forward a bit, he signed up for a local college 2D AutoCad class and now patterns all his knives (tactical & traditional folders), then sends the Cad drawings to the wire EDM guy and waterjet cutter guy. It has revolutionized his 4-knife per week output to well over 10 per week. Now his waterjet cutting guy has informed him he will need a new contractor, as he's retiring. I've been the little angel on his right shoulder encouraging him to buy a CNC mill and waterjet cutter of his own (with ulterior motives, I angelically admit); however, that little devil on his left shoulder keeps on telling him it might take longer to pay back than the internal production would save him.

Well, now he's soliciting quotes to double the size of his shop...
 

lcrken

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So here goes my first post with pictures on the new forum. After some delay, I'm back on the project. This is the current status of my plans for a carbon fiber primary cover.

Foam blanks cut to pattern and being glued together.

Gluing Foam Boards 1200.jpg


Epoxy resin and glass coating for stability and a good finished surface. I used epoxy resin because polyester will dissolve the foam. I will also need to use epoxy for the final CF part, but might use polyester for the mold.

Resin and Glass Coat 1200.jpg


First coat of polyester high fill primer.

First Primer Coat 1200.jpg


Beyond this point, this is a new experience for me. I've made plaster molds before for fiberglass projects, but this will be my first one with a fiberglass mold, vacuum bag, and carbon fiber product.

Next step is Bondo skim and sanding for finished contour, then final coat of primer, which is sanded and polished. When it looks good enough, I can pull a mold from it using glass mat (and maybe also some fabric). Then the interesting stage, vacuum bagging it and making the CF part.

I'm hoping that gives me the final part, but I wouldn't be that surprised if I have to do this more than once to get it right.

Ken
 

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lcrken

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I think this is the final step on the plug. I'm hoping to pull a fiberglass and epoxy mold from it next week.

Plug A 1200.jpg


Ken
 

lcrken

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Well, next week turned into 4 months, but I finally managed to make a mold from the plug today.

This is the plug with two coats of polyester tooling gel coat.

Two Coats Tooling Gelcoat 1200.jpg


Then after the first layers of mat and polyester resin.

First Layers of Mat 1200.jpg


And this is the final mold after more mat and some glass cloth, and some wood reinforcement.

Finished 1200.jpg


All that went pretty well, considering it was my first time at a serious mold. I've done some other other stuff with simple molds, and a nosecone with a one-shot plaster mold, but this is my first time making a mold for vacuum bagging with carbon fiber. It's a time consuming process, because you have to leave some time between lamination layers to prevent it from getting too hot from the curing reaction. It was 6 hours from start to finish.

The big question now is how easily the mold comes off the plug after letting it cure for a day or two. I've been told that can be a fairly traumatic experience. I used many coats of wax, but no mold release, so I'm a little anxious to see how well it goes.

Ken
 

lcrken

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Well, getting the mold off was quite a trip. It was pretty much glued onto the plug, so I had to cut the back out and dig/peel/scrape the Masonite, polyurethane foam, plaster, and fiberglass plug out. Fortunately, the mold looked pretty good after all that. The wood reinforcement/stand got broken off in the process of prying it apart, but it's so stiff that I don't think I need the reinforcing. This is the mold after scraping off the wax and primer that was still stuck to it, sanding off the last of the primer, and patching some pits with bondo. Next step is finer grit sanding, polishing, and waxing. This time I think I'll also use a spray-on mold release.

Mold with Bondo Patches 1200.jpg


I pulled my old GE vacuum pump out of the storage trailer today, and it doesn't work at all. Funny, it was fine when I last used it 40 years ago:(
Fortunately, I can borrow one from a friend.
 

lcrken

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Finally some serious progress. This is a shot of the primary cover all bagged up and curing.

Vacuum Bagging 1200.jpg


And this is the cover after removing from the mold, and a little bit of trimming. There are a couple places where it didn't get pulled all the way into the mold, because I didn't fit the bag material with enough extra to conform to the shape. Live and learn. It's not bad, and I think I can fill in with resin in a few places, and it will still be good enough to look good with a couple coats of clear.


Raw Cover Outside 1200.jpg


Raw Cover Inside 1200.jpg


And this is what it looks like with a little trimming and mocked up on the bike.

Cover on Bike before Trimming and Finishing 1200.jpg


It looks a little large to me, but it is a pretty close fit on the alternator, so I don't think I could have made it any smaller. I still need to trim it down to a small flange, and make make mounting brackets, but that should be pretty simple.

Ken
 
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Finally some serious progress. This is a shot of the primary cover all bagged up and curing.

View attachment 4197

And this is the cover after removing from the mold, and a little bit of trimming. There are a couple places where it didn't get pulled all the way into the mold, because I didn't fit the bag material with enough extra to conform to the shape. Live and learn. It's not bad, and I think I can fill in with resin in a few places, and it will still be good enough to look good with a couple coats of clear.


View attachment 4200

View attachment 4199

And this is what it looks like with a little trimming and mocked up on the bike.

View attachment 4201

It looks a little large to me, but it is a pretty close fit on the alternator, so I don't think I could have made it any smaller. I still need to trim it down to a small flange, and make make mounting brackets, but that should be pretty simple.

Ken
It looks Fan phreakin' tastic Ken
 

lcrken

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Finally some more progress. This is my second try at vacuum bagging a cover, this time in straight carbon fiber. I think this one might be a keeper. I made some changes to the mold for more clearance around the rear iso mount, and it seems to fit pretty well. This is it after rough trimming and cleaning up.

Semi-Trimmed 1200.jpg


Side View 2 1200.jpg


I still have to put a little resin in a couple of places (at the bottom, fortunately) and sand to get a smooth finish, make mounting brackets, and then clear coat it. But I think it will work out. The whole vacuum bagging thing has been quite a learning process.

Time to get serious about foot controls.

Ken
 
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