Topic: 1972 CB500 "An Inherited Basket Case"

[Camrector]

I can't speak on how streetable this motor recipe is, I'm in the beginning stages of assembly,  Mike Reick has said to me that this is will be a great combo. The cam from Megacycle is hard welded and yes you will need you rockers hard welded as well. Did you get oversized intakes when you had the stage 3 port done? Using the 11.5 592r dynoman Wisecos require no valve relief milling with the 126-20 cam. Just a little milling in the head as Cal mentioned.
Coatings I didn't do. No one here can say for certain what the long term effects are of ACTUALLY running a motor like this for many miles. I do know that coatings can come off and clog oil passages. The science is there to warrent Cals opinion of coatings, just not the experience of miles on a 550 heavily modified motor.
Ps you'll love the motogadet and Chronoclassic. I just installed this system on my ladies 550.

[fantino]

Haha, y'all make it hard to not keep spending money I'll have to think on this one over for a little while.

Cal/Cam, the head was ported extensively by Mike and the runners matched, however, I did not end up going with oversized intake valves at the time. When i was planning on running stock pistons and a mild cam, it didn't seem necessary. In hindsight, it wouldn't have been that much added cost while the rest of the work was being done >_<

Interesting on the lipophobic coating under the piston, I hadn't even thought about that.

Cam, I think coating failure is a totally valid concern, although barring incorrect application, I would think the coatings would be more likely to wear away as tiny particles that would be caught by the oil filter.

Valve train coatings would be easy to monitor and crank bearing coatings are so thin (0.0002") that I wouldn't be as concerned about their failure, whatever flaked off would most likely disintegrate. Piston coatings are hard to monitor without tear downs, but I haven't seen much evidence that their failure is common, and folks have been running skirt and dome coatings for quite some time now.

[calj737]

Cam, I think coating failure is a totally valid concern, although barring incorrect application, I would think the coatings would be more likely to wear away as tiny particles that would be caught by the oil filter.

Exactly. They aren't several mil thick, dipped or painted coatings, they're bonded to the surface and they're certainly not "new".

[fantino]

Replaced the primary drive rubber dampers today. I didn't even know this part existed until a couple weeks ago! My general rule is if it's rubber and more than a few years old, it needs replaced.

You can see the difference between the new and old pieces here:



The old ones were quite compressed, and cracked on the surface. They had also become hard with age/heat/oil. I would say roughly Shore A 85-90 vs Shore A 70-75 for the new ones. Much more supple.



There's zero play in the refreshed assembly, where I could rotate it a few degrees before I took it apart. That's certainly got to count for something for smoothing out shock loads to the rest of the bottom end! These parts are still available and not *horribly* expensive, so I'd definitely recommend replacement if you've got the cases open.

I also wanted to take an opportunity to repost the work done to repair the transmission. The shift forks were in quite a state when I opened it all up the first time:





Yikes! Can't imagine this bike was much fun to shift. Probably why it ended up in boxes in a barn. I had the fork ends welded and re-machined:



And also had the engagement dogs on the transmission gears undercut to encourage positive engagement to eliminate further wear on the forks:



This also plays a large part for upgrading to a hydraulic clutch, poorly adjusted and maintained clutch mechanisms appear to be one of the largest contributing factors to wear on this rather troublesome transmission setup.

[fantino]

After much time spent looking over other builds, reading up on top end combinations, looking into cam profiles, etc. I've come to the conclusion that to get where I want this bike to be, more is needed out of the top end. As much as I would like to not let scope and budget continue to creep up... I also don't want to only go "half-way" in.

So, with that in mind - I'm proposing the following changes to the build:

• Pistons: Since the 550 block is essentially plug + play with the head and cases and DP592/61R actually cost a little less than the 572/60R, I don't see any reason to not pickup a 550 block and go for the extra displacement
• Cam: it's clear the 650 cam isn't going to cut it for a high compression, big bore motor. It looks like the 126-20 is the most popular option, despite the minor rework required to the head and rockers. I've been looking at the Webcam 335 a bit too. The 126-20 is quite a bit higher intake lift, but the 335 has quite a bit more duration. I've not been able to find much direct comparison on what effect this has on the powerband for these engines. Dyno sheets would be nice to see to the torque and power curves, but I'm not holding my breath on digging those up
• Head: Unfortunately the intake valves were not over-sized during the original porting work. That's a lot of money in new OEM valves and seat work, but something I'm willing to rectify to get this head flowing right. What I'm not 100% sure on is whether OS exhaust valves are really necessary to the equation. If it's a 1% difference, I'm not convinced it's worth it, if we're talking 10%, sure.

[calj737]

The 126-00 is a great street cam and would probably mate better with your stock intake valves. You didn't mention carbs, so if you run stockers, again, the 126-00 is perfect. Member Flatlander runs a combo of 59mm Wiseco, stock carbs, 126-00, and some extensive work from Mike Rieck on the head. I believe he does have +1mm intakes though. If I recall, his engine made in the low 60s for HP. Thats pretty dang healthy for a 550.

Oversized exhaust valves are pointless. With the 126-00 cam and Wises, no rocker or piston milling is required either. Webcam has a "reputation" for being a touch finicky to degree in, as their timing card is often at odds with their lobe profiles. Very good cams, just "finicky".

[Camrector]

I'm liking it! Twinsies! I believe from what the general consensus is here is that what webcam advertises and what is actual are two different numbers. Member bambuhiphop provided an excellent chart showing Megacycle numbers compared to Webcam numbers here. http://forums.sohc4.net/index.php?topic=124348.0
You did mention that you had rebuilt stock carbs and we're going to explore cr26s.
Cr26s I feel is what you would want from what you are describing above.
With the piston choice of the 61r 592cc, I think you would want the 126-20 as well.
Again those Pistons require no valve relief milling with the 126-20. Plus the extra compression and head work would benefit from that cam.
Larger intakes +1.
Larger exhaust is not needed.
That's the Full Monty recipe.

Another great recipe is what cal speaks of. But with that one you could just use the 61s 592cc Pistons ,126-00, stock carbs, stock intakes.
I'll be doing this on my "sleeper" build.

[SOHC4 Cafe Racer Fan]

Or you could slide in a 674cc, ported and Megacycle cam'd CB650 engine!!  More torque and hp and it bolts right in!

[Camrector]

^ what we all should have done!

[fantino]

Or you could slide in a 674cc, ported and Megacycle cam'd CB650 engine!!  More torque and hp and it bolts right in!

^ what we all should have done!

True - or - if we really wanted to be far more logical, we all should have just bought a better handling, higher power, cheaper, more reliable middle-weight from a later era :-p

I'm far too attached to the bike as a package to ever go to that level of frankenbike. There's a certain level of non-originality I can roll with (this goes up dramatically crossing over from mechanical to electrical), but all in all, I want to stick with the base platform and see how far I can take it.

I'm liking it! Twinsies! I believe from what the general consensus is here is that what webcam advertises and what is actual are two different numbers. Member bambuhiphop provided an excellent chart showing Megacycle numbers compared to Webcam numbers here. http://forums.sohc4.net/index.php?topic=124348.0
You did mention that you had rebuilt stock carbs and we're going to explore cr26s.
Cr26s I feel is what you would want from what you are describing above.
With the piston choice of the 61r 592cc, I think you would want the 126-20 as well.
Again those Pistons require no valve relief milling with the 126-20. Plus the extra compression and head work would benefit from that cam.
Larger intakes +1.
Larger exhaust is not needed.
That's the Full Monty recipe.

Another great recipe is what cal speaks of. But with that one you could just use the 61s 592cc Pistons ,126-00, stock carbs, stock intakes.
I'll be doing this on my "sleeper" build.

I saw that thread, but I don't have enough know how to really understand the differences in duration and lift and how they shape the powerband for these particular bikes. I'm mostly going off word of mouth at this point.

Sorry to style bite But I think you're correct, it seems to be the winning combination to get the best out of this motor. Obviously the carbs are a bit of an investment, but one I was already prepared to make, so I don't otherwise see a huge difference in bumping up to the 126-20 + 592R combo over the 126-00 + 592S.

I can do the head + rocker modification for cam clearance at work, so the only other pieces I will need to send out are for the +1 intake valve mods and having the rocker + cam hard welded.

Luckily I have a windfall of extra contract work coming up in October that will help offset the additional project costs

[calj737]

Send the head, intake manifold, rockers and cam to Mike Rieck in Boston. He will fix you right up! His head work is a thing of master class and he is widely regarded as the Go-To-Guy for performance work on these SOHC heads. He will get you a MegaCycle cam, and be sure to order a slotted cam sprocket for assistance in degreeing in your cam upon return.

Jeff Stephens (Godferrey) has a bolt-on set of CR-26s already set up for the 550s. Now, what about an exhaust system to get the air out? 

[fantino]

Mike is the man! I was really happy with the work he did when I had my stg3 port work done back in 2010. Care and detail of a master craftsman

He actually has my rods right now for polishing and balancing, though there was a minor snag in that one rod appears to not be from the same set! Not sure what's up with that, but the pedigree of this bike is largely a mystery.

[fantino]

Now, what about an exhaust system to get the air out? 

I like the MotoGP exhaust the best, but they seem a little tough to get a hold of? I haven't had any luck so far. The Lossa pipe appears to be very similar, but I haven't seen much buzz about folks running that pipe.

Honestly, I wish there was a good, light(ish) weight performance 4 into 4 for these bikes. I love the look and I love the sound, and there's something about the tunability of 4 carbs and 4 pipes that I find really appealing.

[Camrector]

Check out the Hindle 4-2-1 at ripplerockracers. I have the motogp pipe on my ladies bike, awesome but loud. The Hindle sounds great and the quality is superb.

[Camrector]

Btw are you planning an oil cooler? I'm on the fence.

[fantino]

Check out the Hindle 4-2-1 at ripplerockracers. I have the motogp pipe on my ladies bike, awesome but loud. The Hindle sounds great and the quality is superb.

Thanks for sharing! That's definitely something to think about. It looks well built and the exchange rate is definitely in my favor. I appreciate that it's something different and - though I'm always skeptical - appears to have some solid numbers behind it. The Yosh style pipes, while awesome (and as you say, loud) feel like they have become the de facto pipe for the majority of builds.

It looks like BCR has built some nice looking 4-4 systems for 550s in the past, but I can't justify $1200+ for an exhaust system, especially one that in reality weighs more and likely doesn't offer much difference from a performance perspective.

Btw are you planning an oil cooler? I'm on the fence.

I've considered it, but I haven't seen much evidence so far to suggest it will really be necessary outside of a race track or Arizona. If in practice I see evidence to the contrary, I'll go back down that road again. It's a pretty easy bolt on at the end of the day.

[calj737]

Benjie has a mixed reputation. Some folks have great results with his products, others, not so much. $1,200 for his exhaust is a really premium, especially since its not really performance tuned.

The Hindle is a very well regarded system, probably not truly as "performance" as the MotoGP, but very good nonetheless. And less expensive and more readily available. Unless you're really trying to eek out every last pony, its probably very fine. OR you can make a silent auction offer on the stock, never installed MotoGP set I have cloistered away in my parts cabinet 

[calj737]

Member Elan makes an oil pump rebuild kit with all the "unavailable" o-rings and pieces. Send him along a PM and make sure you get that done while your cases are split.

[fantino]

^excellent advice and reminds me I should check the clearances on the pump rotor to see how it's held up over the years.

I'm on vacation in Montreal right now, so I have no idea why I'm posting right now, haha.

I don't wish to get too ahead of myself, trying to keep my focus on the engine for now, however, weight has been on my mind. I want the curb weight of this bike to be at or below 375lbs (the weight of my Ninja), which is a net 50lb loss from stock. I've added a little extra weight with external hoses and dual disc brakes, but the overall trend is going down:

-Center stand delete (~10-15lbs?)
-crank lightening (3-5lbs)
-Alu rims (3-5lbs)
-Ii-ion battery (5lbs)
-exhaust (no idea what stock weight is, I imagine 5-10lbs potential here)
-phenolic brake pistons (.25 lb)
-cross drilled rotors (.5lb)
-Alu clip-ons, shaved top tree (1lb)

That only brings me, at best, half of my goal ignoring the likely 10+ lbs of additional weight I'm likely to add. Other areas I have ideas on removing weight:

-Fenders: stockers are pretty heavy, but I don't want to run without. I may make splash molds and pull some bagged carbon Fenders. Same deal with side and whatever I do for an electronics tray. If I have a true area of expertise, composites is definitely it. I still dream of making my own tank, but it's a pretty big endeavor. Maybe 5lbs to save here.

-Seat: Stock is really heavy. A stiff carbon base wrapped up in a nice slim leather cushion with some higher density foam (I do a little leather upholstery work on occasion) will save a pound or two, but probably won't do much for comfort

-Frame: if anything, the frame and forks could use extra weight in gussets and bracing. Other than the passenger peg brackets, ignition switch bracket and rear seat rails, I don't see much to lose.

-Starter: I could delete the starter, but I don't really want to. Cost to benefit ratio isn't there for me, especially not until the bike is running well.

-Lighting: slimmer LED lighting all around will probably shave a couple pounds off

-Switches and other electrical: the m-unit, single mg gauge and momentary switches will probably shave a couple pounds off the stock electrical system. Need to find a different horn too, the stocker is ludicrously heavy for what it is.

I'm not sure I'm looking likely to hit my target so far, so any ideas are welcome, keeping in mind I'm not amenable to turning my covers into swiss cheese. Not into the look. The higher up the weight savings, the better.

I've also been thinking about how to plan for tuning the bike. Dyno days don't come cheap or easy and seat of the pants is waaaaaay too subjective and unreliable for my engineer brain.

I'm thinking of investing a little coin in Innovate Motorsports data acquisition and logging units. Primarily I would like to log a wideband, RPM, MAP and a TPS, like a simple EFI setup uses. Manifold pressure is a little tricky if I end up running v-stacks instead of a stock style manifold (EDIT: nvm, just remembered a pressure sensor before a TB/carb is a BPS, not a MAP. Either have to run 4 pressure sensors or run 1 and make the assumption the other 3 are balanced :-/). It would be nice to monitor oil temp, exhaust temp and ambient temp as well.

http://www.innovatemotorsports.com/products.php

With this data I feel pretty confident in being able to setup a series of road tests to quantitatively analyze and optimize carb tuning at the cost of ~3 one hour dyno sessions in my area. Plus I can use the same setup for my BMW 2002 build in the future.

[calj737]

I think you're a bit optimistic with some of your stock weight assumptions. And, shedding 50# of weight off a stock bike of this era is pretty ambitious. Even if you swapped your front rotors to modern units, you'd probably only save 3# net, and I don't believe the stock center stand weighs a full 10#, maybe 5-6.

You could switch to aluminum for all your seat bases, fenders, battery box and swing arm, but again, net weight gain probably won't be as much as you hope. A 4:1 vs 4:4 will be lighter too.

On to your thoughts about data logging etc...

Many of the MotoGadget gauges have data input functions for additional sensors, if you want to install these sensors on your bike. Oil temp, Air temp (engine), but not Fuel Pressure or A/F unless you use the MotoScope Pro unit. If you are swapping up to CR-26s, and dyno tune, you probably don't really need these extra sensors permanently installed, but its up to you.

Know anyone locally with an Exhaust Gas Analyzer that does Emissions Testing? They may be able to let you run the bike at idle, 1/2 and WOT to give you a general idea on your tune before going to the Dyno. And its probably a lot less expensive. And member FunJimmy is running a pretty close config to you with CR's and he's spent heaps of time tuning his bike in nicely. Might give him a ring to get some settings data. He's a knowledgeable and friendly sort with excellent background on the changes/results of his experimentation.

[fantino]

Yeah, you're probably right on optimistic numbers. I went back and checked some of the numbers I had in my head from past builds and I think 385 dry is about as light as I've seen reported on anything that wasn't a radically lightened track bike (supposedly TG and Howell had their builds below 320 dry). Add 30 for gas and oil and 375 wet is a long ways away. Still, I would like to shed weight where I can. Primarily for handling, not P/W. Taking weight off the wheels would probably be the best route in that regard, but I'm not super keen on switching out the hubs or going to a floating rotor setup for the time being.

As for the center stand, I've never had one with this bike, so I was just making a guess

Regarding the Motogadget gauge and sensor capability - there appears to be no provision for logging or outputting the data, so it unfortunately wouldn't help much. I'm not comfortable trying to keep my eye on gauge numbers or operating a menu while in motion. Or trying to remember and correlate any of that information.

I definitely agree that hitting up folks with similar setups for a base tune is the way to go starting out. I'll have to get in touch with Funjimmy, looks like we actually live in the same corner of the world, albeit separated by a pesky border.

The big appeal of data-logging capability for me is being able to collect the response of real world load conditions and to track my riding style. Since carbs require so much more compromise in regards to tuning for max power vs tuning for best driveability compared to say - developing a fuel map for an EFI setup, this sort of data seems invaluable to really dialing the carb in. I can't imagine being setup to collect more data during dyno runs would hurt much either

~$500 for this capability actually seems like a pretty decent value, especially spread over a couple different projects and given that I can recover much of it if I decide to sell the setup later on.

[SOHC4 Cafe Racer Fan]

Personally, I would swap out the stock battery for a AGM battery.  Unless you have tight space constraints or plan to race, Lithium batteries can be finicky.  They have tuns of cranking power, but if they dip below a prescribed voltage, they do not come back.  They seem to be all good until they go in one fell swoop.  I've had three of them work like wonders and then take a crap on me the morning of a planned long ride. 

Shorai has a charger that has a trickle mode like a Battery Tender, so if you are going to buy one, I'd recommend theirs.  It's the one branded lithium that I've had not issues with.

[Camrector]

Never had a problem with Shorais either.
Also
https://www.ebay.com/itm/122128832311
Looks like they are back.

[fantino]

I was aware Li-Ion in general have pretty flat discharge curves, so it's harder to monitor a weak battery as it doesn't give much sign of giving out until it's out of charge. When you say "they don't come back" do you mean the battery permanently will no longer hold a charge?

Random thought... Even if these bikes were running on a permanent magnet alternator, if they were setup with an M-unit and keyless ignition and the battery went kaput, the bike would still be disabled without energy to power the computer. I wonder how tolerant the M-unit is to low voltage and fast power cycles? Does it take a moment to initialize or can it instantly power the ignition system?

https://www.ebay.com/itm/122128832311
Looks like they are back.

I'm about to get some more fun stuff on order as well.

[calj737]

If the wireless key were to malfunction, you can simply bypass it by connecting a jumper from battery + to LOCK. If the battery is too low to electrically start the bike, but would start with a kick, the same jumper can work to excite the m-unit. You'd need to do this to activate AUX which is the circuit you'd use to power the coils.

The m-unit has some built-in features to alert you of low or high voltage events. Circuit shorts are automatically reset, and the circuit re-enabled for as long as the short is arrested.