Topic: 1972 CB500: "An Inherited Basket Case." Finally... AN UPDATE!

[traveler]

Looks like alot of progress has been taking place!

On the gear ratios....keep in mind, that lowering the ratios a tad will actually help the motor out.  Yes, it may lower the top speed a tad, but acceleration, and everything is very nice.  The TRUE difference between a 16T and 17T at top speed isn't going to be more than maybe 1-2 MPH, but the acceleration and the way the power comes on MORE than makes up for it in real around town riding where torque is king.

I feel kinda bad about sending you such worn out crap.  That rear sprocket is brand new, but the plate covering it, etc isn't the best.

Good luck!  What about carbs?  What are you going to do?

~Joe

[fantino]

Yeah, lots of little progress. None of the stuff that makes you go "wow! I'm getting a lot done!", but it all counts :-)

You gave me a smokin' deal on those wheels as far as I'm concerned. You didn't even get the cost of the new bearings out of it! I'll have to post some pics of the hubs, they're starting to look real nice with the casting marks and most of the pitting removed. I'm going to leave them with a nice satin finish (600 grit). As far as the plate and other little bits go... I have extras from my pile of parts. I can also get stuff up to 3/8" inch 6061 made up on a CNC router table for the cost of materials. As long as one side is flat, I'm golden!

With the carbs... obviously a set of CR29s :-p Seriously though, I'd love a set and they're in my long term plans, but I'm too poor to justify that cost at the moment. For now, however, I cleaned and rebuilt a set of stock carbs before I started posting here. I'll try and tune those as best I can. I'm kind of worried about breaking in the rings properly with a set of carbs that are only bench-synced.

[traveler]

Don't worry about it.  The rings won't care whether the carbs are bench sync'd or not.

There are many schools of thought as to how to break in a motor.

My advice, is keep her under 5,000 RPM for the first 500 miles and under 6,000 RPM for ANOTHER 500 miles, then ride her as you normally will.  Change the oil at 1,000 miles, so as to get all the metal shavings that are in the oil out of there!  Don't break her in with synthetic oil....use regular 10W40, (Valvoline motorcycle oil is good stuff, as is Castrol motorcycle oil) and don't let her idle much....she will be VERY hot on first startup, and will need "air" across the fins to cool her down.

As long as the valves are adjusted, the cam chain is tight, and you have oil pressure, it really is pretty hard to hurt one of these motors.

~Joe

[fantino]

Reassuring advice! I'm always afraid of blowing things up, though I know it probably won't happen as long as I'm careful, thorough and smart :-)

I'm really curious as to what sort of HP this bike will make with weight reductions, gearing, extensive headwork and eventually, higher end carbs. I'm not really into this to make a race bike, but it's always a nice perk to have a machine that performs well :-p

I put the front wheel together today. I accidentally laced one set of leading spokes at the wrong angle (four places before where they each should have been) and while putting it right, I managed to put one big nick into the paint. Damnit!



I didn't freak out and make a sloppy mess trying to fix it this time. Finished lacing and truing the wheels (I built bicycle wheels as a hobby\side business for a while, so it didn't take long), and did some light touching up of the gouge with a brush followed by some wet-sanding and a quick polish. The area where the gouge was is a bit darker, but all in all, I think the touch-up went well (you can only really see it if you're looking for it).



The wheel looks great as far as I'm concerned (and that's what matters, right?). Just need to get the last few bits so I can put the dual disc set-up together.

[fantino]

Got my 5-ohm Dyna coils in the mail today! Read too much about charging issues with the 3ohms on 500\550s so these seemed to be the way to go.

[fantino]

Think I may have found all the bits I need to put my dual discs together... guess we'll see here shortly (I sure do love our FS forum though!)

Thinking out loud on some suspension improvements here. Is there any point in putting a cartridge emulator in a pair of forks with the stock springs? I'm thinking not, seems single rate springs are a must to reap the benefits.

I'm thinking of raising the rear a little with longer shocks, but I imagine a steering damper will become necessary to keep the bike from being too twitchy. Any leads on a decent damper for less than $100?

Also looking into getting some sort of fork brace made at a local jet cutter, but I'm still a little undecided on this. Might be an unnecessary expense *for now*. If I'm not travelling at high speeds a lot, I'm not sure how much this would benefit me.

[rangelov]

2 things:

You want to keep the lower count front sprocket.  It will help reduce your clutch slippage (by revving quicker and lugging less).  My 500 had lots of power, and was geared for the highway.  It had great top speed, but it felt like a Powerglide transmission when shifting under power.  Plus, how many places can you ride to 120 MPH?

You can use whichever clutch frictions, you want. Stock or Barnett.  People have opinions.  But you really need much stouter clutch springs than stock to minimize clutch slippage.  I heard CB450 would do the job.  I bought some and the were really big, but never used them.

On my KAW, I used stock (around town), 1 tooth less (acceleration) and 1 tooth more sprockets (long trip) interchangably.  I changed them based on what I was doing with the bike that week .  In other words, it is easy and quick to change.  Experiment.

Do the cartridge emulators.  They're relatively cheap, require minor alterations and (possibly) spring shortening.  But they will improve ride and and control.

[fantino]

Thanks for the advice! Also pretty stoked about that speedo drive plate :-)

I'm with you on the whole gearing for acceleration thing. I probably won't be seeing much time spent above 90 let alone trying to hit 120 :-p Plus I just got a big fat speeding ticket in my GTI while in Eastern Washington last weekend, so I have to play nice for a year or lose my deferral and watch my insurance go up... I'm much more of the feeling that I would like to stay within the speed limits, but get there as quickly as possible.

I was probably going to go with a set of stock plates for now, but yeah, been thinking about heavy duty clutch springs.

Because I LOVE spending money and making things take longer, I'm also adding cable actuated drum braking and a master cylinder off a sport bike with a remote reservoir (to help clean up the bars) to my list of future modifications. Terry in Oz was using a 600/750 Gixxer MC on his brake setup with agreeable results. Still needs to find a spec sheet so I can figure out if the piston diameter is really where I'd like it to be.

Still no word on whether or not a 750 Tach is actually compatible with 650 drive gear. It would appear to be fine as they have the same ratio, but I don't want to proceed until I'm 100% absolutely sure.

[rangelov]

The master cylinders used to (may still) have size of the bore cast in the body along the piston area. My Kaw did, in inches.  The dual versions are about 1/16 larger bore.  My Kaw was 5/8 for the dual disc version.

I would just use your stocker.  Your lever travel may increase, but isn't that much.  When playing with your brake at a stop, the brake lever travel is much greater than when you're actually trying to stop.  The trade off is smaller master cylinder bore, more lever travel, and greater pressure for larger master cylinder bore, less lever travel, and adequate presssure.

[fantino]

I don't have a MC or a clutch lever to begin with, unfortunately. I figure the money I spend finding a stocker (and likely rebuilding it) will run me about the same as a used gixxer lever in working condition. Easier to find parts for as well :-)

Procured a second caliper and disc, so once those get here, I can get rolling on getting that front wheel all together. Planning on cross drilling the discs, and depending on the shape of both pistons, rebuilding them with phenolic ones and a speed bleeder.

I finished grinding down the posts on my extra top triple tree. Once I'm finished cleaning up the casting, filing down edges and getting a nice satin finish on the piece, I'll post a pic. Considering doing idiot lights in the  Probably going to go with a pair of Vortex clip-ons. They're a bit spendy, but I like the look, the angle and the relatively cheap, replaceable tubes.

[rangelov]

Let me know when you get 2nd set of brakes.

I have parts for my Dual Disc Conversion (DDC).  But the calipers don't match.  If yours don't match either, we could swap and make matching sets..

Where do you get phenolic pistons?  I like metal.  But metal corrodes, phenolic doesn't.  Phenolic doesn't transfer heat like metal.  I don't think heat transfer is much of ann issue on these bikes.

Any old master should work.  The only thing you might need to watch for is the mirror mount.  Mine is located on the master cylinder casting.

I installed the Yoshimura 550cc 'big' bore kit and cam kit into the CB500 back around 1975.  I remember it like yesterday.  Couldn't figure out why the engine wouldn't rotate fully after it was assembled.  It was the stock CB500 head gasket, bore was too small, pistons were catching on it.  A new head gasket fixed that.  Bike was sold long ago.

[fantino]

I'll let you know when parts start to roll in. I already have a mismatched set of discs (one is like... 3/4" of an inch bigger. I don't remember if it came off the 550 or 500 wheel I had). I know the parts coming in are off a 550 and I'm running a 550 front end now, so we'll see what matches up.

Here's the dude who sells the phenolic pistons, he's a forum member here:

http://forums.sohc4.net/index.php?topic=75769.0

I prefer metal as well, but these are 2/3 the price of DSS replacements, and like you mentioned, don't corrode. Also I guess you don't need that nylon washer either.

Wish I coulda seen that Yosh stuff. I love period performance parts.

[fantino]

I accidentally put a big chip into the left fork lower today ~_~ Hate hate hate paint. I'm stripping anything made of aluminum and bringing it to a satin finish. Can't bother to put up with anything less durable than a bare metal finish (except the rims...), even if it means periodic buffing.

[Kemp]

For the clutch issue on the CB500 use a combination of CB500 metal discs and the CB550/650 friction discs. I forget just what the combo was I used but it's either the Cb500 or 550 or 650 metals are thinner . The thinnest ones are what you want. The CB550 or 650 cork plates are what you need as they allow the oil to pass through much better than stock CB500 so they don't slip. Just use stock springs. Aftermarket springs are too stiff and you'll wear out your clutch hand for no reason. If you build the clutch as mentioned, you'll end up with an extra metal and friction disc with exactly the same stack height as stock plus the clutch action is smoother, will not slip and no increase in lever effort.

I dropped one tooth on the counter shaft on my 500 (16t) and it makes a big difference in acceleration and top speed. The 500 does not have the torque of the 550 and must rev a bit harder to move so dropping a tooth really wakes these guys up. There is no downside as the slight increase in revs just makes the bike pull better in each gear effectively tightening up the ratio a bit. Top speed is more achievable at about 102-104mph on your speedo as the bike can stay within it's max torque/hp band a bit easier as you go through the gears. With stock gearing it really just falls flat. In the day this little change made all the difference in the flexibility of the engine to pull highway speeds and accelerate to them. This lack of torque was probably Honda's biggest reason to increase displacement to 550.

[rangelov]

I already have a mismatched set of discs (one is like... 3/4" of an inch bigger.

I was looking at my rotors.  It appears the the brake pad doesn't contact the outer 10mm (3/8") of the rotor.  The rotor can be 3/4" smaller in diameter and fully contact the brake pads.  If that's true in your case, you can use the smaller rotor without any problems.  But check first.  If that works, you can cut down the larger rotor.  I think you have access to a lathe or a machinist.

The downside is: this may be more involved than getting another rotor.  You'll lose some thermal mass, but that is inconsequential, since you're doubling the braking, anyway. 

Turning down the OD, will lose weight from material removal and reduce inertia since it from the OD.

Anyway from what I have read, the 500 rotor is slightly smaller diameter than the 750.  What are the OD measurements?

[fantino]

Yeah, just checked the two discs. Looks like one must have been of a 750 (~295mm) and the other is off a 500 or 550 (~275, IIRC). The disc I picked up should be the smaller size from a 500\550. We'll see when it gets here.

I guess Mrieck is done porting my head, it's off to the machine shop next week and then back to me! Very excited.

I've only really been doing cosmetic stuff the last few days. Polishing up parts, shaving my top triple tree and the like. Pretty poor for a little while here, so I need to keep focusing on these projects :-p

I've finally settled on what I'd like to see in a fuel tank for this bike. Something along the lines of this, though with some modifications to a few of the curves as well as filler cap style:



In addition to the nice deep knee pockets of this BCR tank:



Just a coincidence these are both yellow, I'll be sticking with raw carbon :-p

[an old man returns]

I have a mastercylinder (needs a refurb) and brake (needs a refurb) and brake disk are you on 4 bolt or 6 bolt hub.

If your interested will weigh parts for you to sort carriage. The price of the parts??? a 'drink' will do

[fantino]

an old man returns: That's a really great (and generous!) offer. Unfortunately I already bought the components like a week ago from another forum member. I still haven't heard back if anything has been shipped yet... If things don't work out and I have to get my money back, then I will definitely hit you up. Thanks!!!

Working on some hub weirdness. It looks like the hub I got from Joe has the rotor surface projecting out 4mm further on the speedo side than the other two hubs I have. You can see this difference in these two pictures:





So this means the rotor would not sit in the same place and it also causes interference issues with the speedometer gearbox. BUMMER. That other hub has some pretty big issues, LOTS of rust going on in the spacers and I don't really want to refinish it or change the bearings. SO I'm going to look into either rotor or hub machining to take off that 4mm.

The flats for the speedo retainer were 56 mm apart on this hub as well, instead of the 52mm found on other CB hubs. This was easily fixed with 10 minutes and a file. I marked off with a sharpie the material that was removed. Accidentally filed through the tape on the hub surface... whoops! Oh well, that'll be covered by rotor anyways (or machined off...).

[rangelov]

It looks like the one rotor mounting surface is moved back 4mm and everything else is the same except the distance between cutouts.

Just a thought, if you have a large lathe, you can cut the hub down without removing the rim.  You would locate the hub (bearings) between centers and drive the wheel with a lathe dog.  As long as the tailstock is aligned, you should get a square cut.  You could even mount the second rotor and trim the OD using this method.

Have you checked how the 2nd brake caliper and arm align with rotor using this hub?

[fantino]

Well, I sucked it up and took that front wheel apart and relaced it to my original 500 hub. Wasn't that bad. I managed to do the whole process up to tensioning and mostly truing the wheel in about 45 minutes. I get faster at this every time I do it. I didn't even put a nick in the paint this time either!

Lo and behold, everything fits perfectly:





Look at all that clearance!



Anyways, I still need to put new bearings in, but I've made a deal with Terry from Oz to give him the K0 hub (and a K0 disc I magically had laying around) for the cost of bearings and whisky, haha.

Still waiting for my cylinder head... getting more and more excited\anxious every day!

[rangelov]

I'm glad it wasn't as painful a process that it was thought to be.  And your parts match up with what is supposed to be on your bike.

You seem to have more clearance between the bolt heads and the gearbox than I do.  When mine isn't engaged fully, I have just over 0.100" of clearance between the driver and the gearbox.  When fully seated and engaged, there is about .010" of clearance.  My driver adapter is sits pretty much flush with the rotor.  Yours looks like it sits a bit higher than the rotor.  My gearbox just barely touches the bolt heads.  I'll chalk these differences to model year differences and casting & machining variations.

It looks like you're ready to mock up everything to modify the caliper mount.  Reading another post, it seems to be easier to mill the bracket pivot than it is to file down the post on the fork leg.

Makin' progress!!!

[fantino]

Slowly but surely, I do somehow manage to keep making progress on this. Never as much as I would like though, haha.

Something shifted when I took that third picture. Normally the adapter sits absolutely flush with the rotor (It really is a *perfect* fit on the 500 hub). So the clearance is a little less, but still totally acceptable. However, I am considering countersinking some allen head bolts into the rotor a teensy bit for peace of mind.

Not much progress to otherwise report this week... finished all my sidecovers and such. They're all a nice satin finish now. I've been toying with the idea of acid etching something into them... a pattern or whatnot. I still need to strip and satin-ize the forks as well. No more chipping paint for me!

Still trying to source a set of original pipes... waiting for some pics from a forum member, hopefully they're decent and he's willing to let them go for a price I can afford. They may be heavier than my turnouts, but damn, I just love the original exhaust on these things.

I also looked into getting a set of 2-1 cone eng. collectors for my head pipes so I could put on to of those slip-on JCWhitney Dunstall pipes. Most people seem to say they're way too loud though. Kind of a deal breaker for me. If it's going to be loud, it had better net me a huge performance gain. Somehow, I doubt that pipe would.

[rustbucket]

Hey fantino -

Do you have any further information about running external oil lines? I did a bit of searching, but no joy so far...

[fantino]

It's not too difficult of an endeavor, but there are a number of steps. You have to first block the existing oil passages going from the upper crank case to the head. I blocked the crankcase passages by putting a setscrew with permanent threadlocker in the oil passage under the upper bearing shell on either side of the crank. If you're not planning on splitting your cases right now, others have just blocked the cavity where the oil restrictor jets meet the block. I did both for good measure.

You have to block the passages in the head in a similar fashion. You will also need to remove the aluminum plug that is pressed into either side of the head. I drilled mine out to tap and fit an M6 bolt. A couple taps with a hammer and the plug will come right out.

The easiest place to feed the oil lines is from the right (points) side of the main gallery. There is a drain plug you can replace with a specialized fitting (I have an M20x1.5 to AN6 adapter). Others have drilled out a plug and tapped it for a fitting. The only downside of feeding the lines from the right side is if your adapters stick out too far, you can damage the fittings and the cases if you crash that side. At the very least, you'd probably have a big mess of oil on the road. TG made a skid plate before moving his lines to the oil pump, and bwaller says the 650 points cover is a lot beefier than stock, but doesn't quite line up without a little modification.

From there you just have to put together your lines. I'm going with braided AN6 hose from the gallery to a AN6->AN4 tee junction. You need to have oil restrictors somewhere in your lines to maintain pressure in the main gallery, the tee fitting is an obvious place. From there, I'll be running AN4 hose going to either side of the head with banjo fittings. Helicoils don't seem like a bad idea here either.

These are the only two threads I've really seen on the subject. There's some good pictures to make all this a lot clearer.

http://forums.sohc4.net/index.php?topic=24881.0

http://forums.sohc4.net/index.php?topic=24837.0

[fantino]

Oh, and in other news... My head is now in the mail, on its way from Mriecks doorstep to mine :-D Exciting stuff. The block is out getting bored and milled as well, should get them both around the same time. I also bought some stainless bolts for the head and side covers. Still need to sort out clutch plates, probably going to go with the solution Kemp mentioned (found more info on it in a Gentlemans express thread). Really, the engine is pretty much ready to go back together.

I disassembled the forks again. Going to strip the paint and "polish" the lowers, since I'm unhappy with the paint. Probably install MikeXS emulators while I'm in there.

Also found a 4-4 stock exhaust I can use until I'm able to afford a Kerker or Marshall Deeptone. There's some corrosion on the header chrome and some rot on one of the mufflers, but I'll probably just cut the section out and weld on a piece of plate to keep everything sealed up. I'll probably spray the headers with silver exhaust paint to cover up the corrosion.

Lastly I decided to just use the zinc chromate nipples from the DSS spoke kit. It's not that noticeable and it will save me like 40 bucks + hassle. If I hate it that much, I'll just rebuild the wheel. Still trying to decide on tires. I'm thinking Shinko's to start off with, so I can get the bike mobile again. Upgrade to Avon's when I can afford it.