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Discussion Starter #41
Lastly, for now, was to change the chain. Went from an economy DID to a Renthal R1. The DID chain is at least 10 years old and was stretched by a half link compared to the new Renthal. Weighed them for the heck of it, and was pleasantly surprised. Especially considering there's probably another few grams of thick tacky wax on the new chain, while the old one is pretty dry.

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Discussion Starter #42
Almost forgot that I weighed the bike a few months ago. Used a 2x10 board laid over a bathroom scale, that weighed 17.2 lbs on its own. So subtracting that, the bike is 217.4 lbs, now minus a few ounces of weight savings since the picture was taken. Aside from losing 5-10 pounds myself (I'm not big), and more extreme measures like a custom frame (maybe someday?), I think the only real additional weight to lose, safely, would be from an aluminum tank and lighter custom exhaust.

(In the photo, the bolt holding the shifter arm was loose for adjustments.)

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Incredible. That's what, 80lbs lighter than a stock CB160? I can't find stock weight for a CL to compare.
 

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Discussion Starter #44 (Edited)
Nah, I think it's more like 50 lbs saved.

I'm about to fit a vert head to the sloper engine. Need to make intake and exhaust manifolds. To do it, I had to bring the bike into the living room. It's the only way.
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Discussion Starter #45
Making the intakes. (My machining makes up for my welding.) Not done, the intakes need to be curved.
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So were you calling that good, or having someone reweld it for you? Just a suggestion, but you might try using more heat and slowing down until you see the base aluminum turn shiny, then dab your filler rod into the puddle, moving forward in a slow rhythmic fashion along the joint. Even better yet, before lighting up on that piece again, spend some time at www.weldingtipsandtricks.Com and practice on some scrap. Your machine work is so awesome it would be time we'll spent bringing your tig skills up to match. You'll be stacking dimes before you know it, just takes some practice.
 

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Discussion Starter #47
Was MIG welding from a spool gun, with the wrong feed and voltage settings. A bit out of practice. Saved that ugly picture for dramatic effect. Ground it down, rewelded (better), then machined. Work is now solid; no bubbles, gaps, or voids. TIG would clearly be preferable, but I don’t have that yet.
 

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ah, i see. aluminum MIG is a whole different animal, you can tell by it's poop. Lol. i think you will find TIG much easier for aluminum when you get there.
awesome machine work!
what do you have for a lathe, if you don't mind my asking?
 

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Discussion Starter #49
LMS (Little Machine Shop) 5100 7x16 Mini Lathe.

I am space-challenged, so I had to go with a bench top machine. I do all my work in a cramped, 6'x10', very well-equipped shed on my back patio. Whatever I do is self-taught with the help of Youtube. And I'm a physician. So when things go wrong, I get to say "I'm a doctor, dammit, not a welder/machinist/mechanic/etc!!"

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My hat is off to you. I thought I was challenged for space. Years ago when I was contracting/building houses, I was at a doctor's appointment and my doctor had his arm in a cast. I asked him what had happened, he said that he was doing some home remodeling. We made a deal, He would not do any more carpentry and I would not pratic medicine.
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Instead of a "tiny house" you have a fully functional tiny machine shop, that's too cool!
 

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Discussion Starter #52
Because I'm fitting a vert head to a sloper engine, the intakes had to be curved for the carbs to clear the frame and sit level. Cut some pie slices out of the tube to make the bend.

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Discussion Starter #53
Skipped the picture of my ugly welds (they weren't as bad as the first time). In the end, these came out better than expected. Still waiting on some G-7 phenolic plate to make heat insulating spacers between the intake and the head. Then I'll port-match all of it.

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Discussion Starter #54 (Edited)
Pretty much finished the exhaust. Like the intakes, I had to make up another exhaust system to accommodate the port angles of a vert head on a sloper bottom end.

Started with 1" tubing in bends and straights, a merge collector, and a couple of cones, all from Cone Engineering. Just mild steel.
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Cut slots and wedges out to bend further into shape to replicate the stock scrambler pattern. It's laying on the floor behind the bike, next to the reverse megaphone I made. The exhaust collars were machined out of some scrap aluminum plate. Will probably fenestrate them in the future.
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I did all this in the cramped corner of another shed on my property, where I store a car and gardening tools. No room to work, but somehow got it done. If someday I retire, I'd like to build a big, well-lit, HVAC-equipped shop.
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Made a stout exhaust hanger out of a scrap strip of titanium. Had to heat it red hot to bend into shape.
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Can't really see it except from the other side. It's mounted to the frame on a rubber bushing to isolate vibration. Didn't do this before, so I'm interested in seeing how it will feel and how long it will last.
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Discussion Starter #55
Here you can see the reverse megaphone I fabbed out of two separate cones welded together. Exhaust cones are a tricky business. I copied the dimensions I made for the previous exhaust because it was worth a few HP vs. straight pipe when tested on a dyno.
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Brought the bike back into the living room after the welding and painting was done. Used VHT rattle can header paint. I've had ceramic coating in the past, and feel like this paint is about as good.
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Heat shield was some left over aluminum sheet I bought from the Boeing factory's surplus outlet about 15 years ago, back when they sold this stuff directly to the public. Crazy cheap, sold by the pound. $3/lb. for Al, $5/lb for Ti, or something like that. I have a stack of sheets of all kinds of aluminum (6061, 7075, etc) and even some titanium. This piece could very well have been from a sheet designated for a 737 fulelage. Or maybe a military application... The holes aren't evenly spaced because I eyeballed and freehanded it. More organic that way, I guess.
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There's some trickiness to the headers behind the collars, where they reduce in size from the port to the 1" tubing. Maybe I'll show those when take this apart again someday. And when I do, I should also weigh this system. Pretty sure it's a bit lighter than the previous one.
 

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"Brought the bike back into the living room "
I love this! There is a thread on here somewhere for posting pictures of your bike in the house. I once made a set of aluminum exhaust flanges and split collars for 66sprints land speed record bike. There should be pictures of them on that thread. Looking at yours, I am thinking that they should have slots cut around them to make fins like the ones they used to use on the British bikes.
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Discussion Starter #57
Made some port-matched manifold spacers out of this G-7 Garolite to keep the intakes cool. It's a modern heat resistant version of Bakelite. Expensive, about $30 for this small 1/4" thick sheet.

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Discussion Starter #58
Going to backtrack a bit.

Was previously using a Megacycle cam that came with the engine when I first got it over a dozen years ago. For this build, I'm using a stock (and rough) cam reground to fresh stock profiles. Added a Cappelini adjustable sprocket. Pressed on with red threadlocker.

A sharp eye will notice the cam got a nosejob, too. I'll get to that later.

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Discussion Starter #59
Head was machined so the cam would ride on roller bearings. Done by the late Mike Riddle a couple years ago, just a few weeks before he died unexpectedly. He was an excellent mechanic who did this stuff as a hobby. Great guy, and a real loss to anyone who knew him.

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Discussion Starter #60
Almost all of us who race these bikes run a Pertronix ignition through a total loss battery system. I've had DNFs because of dead batteries, and DNFs from failed Pertronix when the magnet busts out of the brittle plastic rotor after years of use. When the magnet lets loose, it punches out a little square window in the plastic rotor, so I switch the 2 magnets 90° to keep going. Assuming I can find and retrieve that little square magnet. See, these Pertronix units were originally designed for 4 cyl. VW Bugs, but we remove two of the 4 original magnets from the rotors for our 2 cylinder application.

Here's how it's supposed to look:
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But here's how it looks when it fails and costs you a race. The 3:00 magnet failed, so I buggered up the rotor trying to remove the 9:00 magnet so I could shift them both to 12:00 (done) and 6:00 (pending):
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I got sick of this monkey business (since I've had to do this more than once over the years), and keeping battery packs charged for a race weekend is a constant source of mild anxiety. We don't run regular Yuasa lead acid batteries anymore; most people have small Li-ion packs that have to be swapped out and kept charged up between sessions.

So I ditched all that and installed a programmable CDI ignition system; 2 curves, with rev limiter. Which is why I could get away with lopping off the cam's snout and install this sleek cam cover on the wrong side.
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