Topic: 1982 CB650SC, Project: "Black and Blue"

[tourmax]

Well, brake bracket 2.0 didn’t go quite as planned, but it will form the template to make the final pair from:



Yep, looks good. Now, another couple days of whittling aluminum to get to the finished products.

[tourmax]

Final form for the caliper brackets:


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Not too shabby!

The rh bracket is already built, the lh bracket provided a template and then it was just a matter of whittling it out on the lathe/mill. All I have left to do to it is to whittle out the caliper mount points so the caliper is properly centered over the rotor.

Next is to drop the engine and give it a good cleaning and sone paint. Then strip the frame, clean the rust and a coat of black enamel.

By the time thats all done the rear r6 wheel ahould have arrived and I can start work on that.

[tourmax]

Rh side went much quicker with the lh side bracket providing the template:



Thats a lot of brakes for a 50-60 hp middleweight!

I think next I’ll pull and paint the engine. Nothing fancy, just the standard “Nighthawk” black with some polished bits.

Which means the next logical step would be strip and spray the frame….

[Stev-o]

Thats a lot of brakes for a 50-60 hp middleweight!

Was just thinking the same!

[tourmax]

Thats a lot of brakes for a 50-60 hp middleweight!

Was just thinking the same!

Just means you can run them hard and not get brake fade.

I’ve been known to be a pretty heavy late braker. I’m also a trail braker at times as well as someone who makes heavy use of the rear brake.

Used to amateur race when I was just a pup and it developed a lot of habits that I still use today.

Guys I ride with never seem to follow my brake markers into a turn as they’re usually past where the “average” rider is comfortable. I never ride at 10/10ths, but I’ve been told many times my 7/10ths is well past someone else's 10/10ths. I’m usually just cooking along and enjoying the ride while my “less experienced” buds are either struggling to keep up or watching my tail light disappear around the next bend and knowing they probably won’t see it again until I stop for a coffee or pee break (which happens far too often now that I’ve got more mikes on my odo)…;)

Truth is though, I’m more of a builder than a “racer” these days….

[tourmax]

Still waiting for the r6 rear wheel, so I decided to chuck a 17” 5.5 rim in there to get an idea for fit:





Thats a rim from a zx7 and 170 tire IIRC. Not exactly in place, I just rolled it into the open swingarm for a quick visual. Fits pretty good overall. The chain alignment will be the only real question it seems….

[tourmax]

Slid an axle through the wheel and swingarm to get a better view:





This thing is starting to look pretty serious!

Too bad it’s “bite” won’t be as big as it’s “bark”…but it will sure have a presence!

Lol!

[Ramrod_Racing]

The chain alignment will be the only real question it seems….

I see an offset sprocket in your future, but considering the problem solving you've already done to get this far that doesn't seem like it will be much of an issue for you.

You're giving me a run for my money in the "Most parts not intended for a '82 CB650SC Installed" title.

[Alan F.]

Are you thinking of a 520 (3mm narrower) chain or keep the 530?

[tourmax]

Are you thinking of a 520 (3mm narrower) chain or keep the 530?

Don't know yet, too early to even guess. I'll need to get it all installed before I will know how much of a problem the chain will be. Then, I can look at options for more clearance if needed.

[tourmax]

Well, sitting here thinking about the speedo drive. The problem is getting it even in the ball park (let alone accurate) with a mish-mash of components. As we all know, changing even tire size throws a cable driven speedo off.

So I need a way to fine tune the speedo to whatever drive I make. With the VFR400 drive, a few options are opened up to me.

The VFR400 drive is intended to be direct drive off the countershaft sprocket. What I'm going to look at is moving the drive away from the countershaft and then use a couple gears to take the drive from the countershaft sprocket to the VFR400 drive. This will allow me to do a few calculations and use two gears to step up or down the rpm the drive sees, which will allow me to fine tune the speedo by selecting different gear ratios. Essentially, I'll be making my own geared "speedo healer". Getting gears won't be a big problem, I can cut them myself of the lathe if needed. I just don't particularly fancy hobbing gears, but ya gotta do what ya gotta do.

I'm also thinking of replacing the gauge faces with the CB900 bol d'or faces:



Sure, the speedo goes waaaay too high for a cb650, but I can calibrate my drive to at least make the speedo accurate. Plus, those will look pretty cool in the nighthawk's binnacle. I need new faces anyways, the replacement CB650SC cluster i bought turned out to have "melted" faces. No idea why they're melted, the melt spots aren't even close to where the illumination bulbs are. The seller was very "coy" and made sure he didn't take pictures from an angle that shows the melted faces.....

[tourmax]

The "new" rear r6 rim just showed up. Tossed it on and took a few quick looks:



Whoowee! That's a really big misalignment!

It's at least the full thickness of the front sprocket, if not more. Not too big to be compensated for, but that's probably the biggest discrepancy I've dealt with yet for chain alignment on a wheel swap. On the other hand, the chain actually lines up with the RD500 swingarm chain guide so that's a plus! 

The rim is only "eyeball" centered to the bike (I have a laser jig I use for final alignment), but you can see there's quite a bit of offset to be taken care of. I'll likely have to do a combination of shaving the sprocket carrier and an offset front sprocket. I can usually get somewhere around 4-5 mm with a carrier shave, the rest will have to be the front sprocket offset.

May have to chop up the engine side cover for clearance, but I was going to have to modify it anyways to fit the speedo drive. might just cut the recessed part of the cover off and weld it back together flush with the front part. Welding cast Al is a pain, but at least this isn't structural. It's mostly there just to keep your pant leg out of the chain/sprocket and keep grease from being thrown on your bellbottoms. LOL!

I've dealt with offset before in a number of ways: stepped sprocket, shaved carrier, spacers, etc but I'm thinking this time I may make an "adapter" to bolt to the countershaft and then bolts the sprocket to the adapter. That would allow me to use standard countershaft sprockets without having to alter them. I'll need to need to sit and think about that COA for a while....

The wheel bearings are also mega huge compared to the RD500 rear axle. Not surprising as most modern sportbikes use those huge, hollow axles these days. I'm not going to mess with searching out bearings that fit the wheel and the axle, so it looks like I'm going to be machining spacers and bushings (like with the front wheel) again.....

[Alan F.]

Looks good, manageable.

[tourmax]

pretty sure I know what i'm going to do with the rims for colors:



That's a photochop on a rim pic I grabbed off the net. well, I grabbed a pic off ebay of a CB650F rim and modified it to end in "SC" and added the blue tape stripes.

Now to find a shop that can print those out without wanting my left....errr.... "wedding tackle".....

[Stev-o]

^^^that looks awesome^^^

[tourmax]

you know, the more I think about that offset sprocket, the more I think I'm going to have to make and outside steady bearing for it. The OEM sprocket can wobble around on the output shaft as it is (I'm assuming it's built like this to account for production tolerances on the chain alignment) and pushing the teeth further out from the center is going to allow it to flop up and down as well as wobble when running.

That's a resipe for disaster!

So I guess i'll have to take a page from the drag racers build bible and build something like this:

[tourmax]

well now, this gives me a couple ideas:

[tourmax]

Oh dear.

Got the laser tools and plumb bobs out. The rear wheel is hard up against the sprocket carrier on the swingarm and it is still a good 10mm off centerline.

While you can run a wheel off centerline on a two wheeled vehicle, it usually means it resists leaning into a curve one way and falls into the lean the other way.

Seems I’ve got some serious shaving to do and then just deal with however much offset there is at the drive sprocket….

[Alan F.]

Now would be a good time to consider tire size

[tourmax]

Now would be a good time to consider tire size

170. you can squeeze a 160 on a 5.5 rim, but you're at the very lower edge of the recommended sizes. you can go up to a 180 (which is what yamaha spec'd these 5.5 rims for), but then you're going to get more "bulge" in the sidewall, which will be a problem on my bike. 170 is "more or less" the industry standard for a 5.5 rim.

Now, it also has to be said that all 170 tires are not created equal either.....

[tourmax]

It looks like the fuel tank is going to be salvageable. I first pulled out as much of the Kream liner as I could. then rinsed the tank many times with clean water. Then, I dropped a couple handfuls of old nuts in the tank and taped it up.

Conventional wisdom is to then shake and roll the crap out of the tank for a couple hours. Well, I'm old enough and broken enough to know that you need to work smarter not harder.  So I wrapped the tank in a couple yards of bubble wrap. Then I wrapped it all in a king sized comforter and jammed it all into the clothes dryer. It was packed in tight so nothing was going to be banging around in the dryer drum. St the dryer to tumble (IE: no heat) and let it go for a couple hours.

Pulled it out, pulled the tape off and started rinsing with clean water. More rust came out of that sucker than I can describe. then used a magnet tool to get the nuts out of the tank. Finished off with dish soap and clean water rinses.

Tank looks pretty good inside no leaks from the seams or anywhere else.

Next step is to let the tank dry thoroughly inside and dump in a couple liters of rust remover/converter to handle the little bit of surface rust left inside.

Once it's all done, it will be time for a good tank liner product. Haven't settled on which one yet, but I'm pretty sure it won't be "Kream".......

[tourmax]

Was having a heck of a time mounting the sprocket carrier to the lathe. the drive tabs on the underside o fhte carrier are arranged just so that I can't use either the 3 jaw or 4 jaw chuck to fix it the lathe.

Well, what to do? I need it on the lathe in order to cut it down square. this is not an area where you want to do this freehand.

Then I struck on it. I changed the chuck out for the face plate. I was then able to bolt the carrier to the face plate through its drive dog slots to the holes for hte sprocket studs. Got it to within 5 thou center, which is good enough for the facing cuts i need to make.

this thing is turning into a bigger project than I had originally wanted......oh well, I'm up to my neck now, no turning back!

:p

[Alan F.]

My lathe is too tiny, so I blocked mine up on my tiny mill and cut it that way. Good work with the faceplate, you can do so much more that way.

[tourmax]

My lathe is too tiny, so I blocked mine up on my tiny mill and cut it that way. Good work with the faceplate, you can do so much more that way.

My lathe isn’t that big either. Its an old 1950’s era Atlas th42.

42” between centers, 10” headstock so 5” swing.

Does most everything I need. Anything larger I will farm out to a proper shop.

[Alan F.]

That's not too tiny, I've got an old green Harbor Freight from the 80's, 7x10 is an exaggeration. Old machines just make me happy.