Topic: Ride report and ready for mods

[WaxhawFive]

I've had my '75 CB550F for 8 years and used it mainly for short rides, often with a passenger, around town.  Sunday I decided to take it on a longer ride into the mountains with my father-in-law on his R1150RS beemer.  We did 365 miles at a brisk pace.  The worst part was the boring 90-minute highway ride to get out of Charlotte into the twistys, but once there I was blown away by this bike.  It handled the 75-80MPH highway stint with ease, like a sewing machine. I wasn't sure how it was going to feel in the tight stuff (up to Saluda, then Cesars Head, Bat Cave then 9 to Black Mtn.), but again I was completely impressed.  So much so that I'm putting off the purchase of another sporty bike and instead want to sharpen the focus on this one.  New tires will be first, then suspension upgrades front and rear, and maybe a little brake upgrade too.  I'll be reading the suspension threads for recommendations, but any suggestions will be appreciated.  Love this bike and can't wait to head back to the mountains.

This pic is atop Cesars Head, grey-beard is my father-in-law.

[denward17]

Sounds like a great time!

Following for info myself....

[WaxhawFive]

Before buying tires, I wonder if now is the right time to reconsider wheel sizes?  What is the best option to get modern tire sizes on a classic-looking wire-spoked wheel? 

[Don R]

 I've done a couple 750 double disc swaps and am sold on it. I like stock sanded pads and also re-finish the rotor.
 Some 550's used the 341 fork lower, the same as a 750 just with shorter tubes, a smaller rotor and the brake bracket is angled down. Some 750 guys have used the 500/550 brakes on a double conversion to keep the weight down. Or you might be able to go to a 750 single set from a 75/76 F which is my favorite caliper. All of mine use a stock M/C, the same pressure but more lever travel.

[seanbarney41]

I feel like dual discs are overkill for a 550 as all that extra weight will ruin the very light, neutral steering of the 550.  There are plenty of good tires to fit the 550, just not the latest super high performance rubber that only ever comes in 17".  Maybe consider building stock diameter wheels with some slightly wider than stock Excell aluminum rims?  Lots of vintage race guys run 18" front instead of 19", but be careful not to alter your steering geometry too much and go too far with big rubber and you will just tie the flexi frame into knots. Some Ikons in the rear, and race tech goodies (springs and cartridge emulators) in the stock forks should make for a very enjoyable vintage ride.

[Stev-o]

+1...I dont think the 550F needs dual disc  [I have a '76 550F], at least not if the motor is stock.
Good rubber pumped up to 37psi on the front and the bike will go anywhere you point it!

[MauiK3]

Less mass needs less brake.

[scottly]

Less mass needs less brake.

The 550 has less brake (smaller rotor) than a 750. How much less does a 550 weigh than a 750?
Like Don mentioned, the 750 rotor and caliper can be used on a 550 to improve the braking while retaining a single disc, and if the rotor is thinned it won't add any weight over the stock 550 system. Horsepower doesn't enter the equation; brakes are for stopping, not accelerating.

[bryanj]

Back in the 70's i twin disced a 500 four just because i could.
One caliper in front, one behind because the 500 only had mountings on one side and an early GL 1000 master, it did stop better than the single disc but to be honest you had to be riding like an utter lunatic to need it, plus with an aftermarket exhaust you could bottom the forks and jam the mudguard between the two centre downpipes so you could only go straight on, the policeman stood on a corner of the Isle of Man circuit did not like that!

[WaxhawFive]

Thanks to you all.  I will look into a swap to larger 750 rotors to keep the unspring mass down.  I don't want to do dual brakes up front for the reasons mentioned, keep it light.  I really like the idea of swapping for aluminum rims.  If I do go with 18", is it as simple as lowering the rear the same amount as the front to keep the geometry correct?  I've built bicycle wheels several times, so I'm guessing this is similar, and I'll have it all trued and balanced by a pro when they mount the tire.  Also, if I go 18" on the front, should the rear drop to 17", or keep it at 18"?  Who is a good vendor for aluminum rims? 

So Race Tech front and Ikon rear?  Any other recommendations? Is there a preferred vendor for our CB suspension stuff?

[scottly]

Another way to improve the braking is to replace the stock 14mm master cylinder with a smaller 12mm or 1/2" MC.

[seanbarney41]

Excel brand aluminum rims are highly rated. You can get a set from Buchanan’s plus their stainless spokes. Have them laced, tried and balanced locally.

18/17 is a good combination for maintaining the geometry and increasing the tire choices.

Many like Ikons, but they don’t have any adjustment for damping/rebound (depending upon how important that is to you). I think YSS makes an appropriate rear shock to the aesthetic that also includes adjustability.

I think 18/17 is gonna lose a lot of ground clearance...to much?  I dunno...I have seen some really angled off stator covers...not pretty.  Plus, it's gonna look funny.  When you run 2 18's, you are trading stability for fast turn in.  I know it works on a 750.  550 is already a bit twitchier, so maybe too much?  Certainly would not combine 2 18's with longer rear shocks.
    iKon totally has adjustable compression damping, so not sure what CalJ has seen.  YSS are good too and there are other even more expensive and exotic stuff out there.  It's just tough to find.  Most 550 owners care only about having nice chrome on the stockers.

[HondaMan]

I'd recommend the Avon RoadRider series tires in normal sizes (100/90x18 front 110/90x18 rear) like these:
https://www.jpcycles.com/product/avon-roadrider-mk-ii-tires?utm_source=Google&utm_medium=cpc&utm_campaign=JP-PLA-Tires-PMax&gad_source=5&gclid=EAIaIQobChMInNLKtcPzhwMVls3CBB21GwjqEAQYASABEgInHvD_BwE

They have a slightly taller profile in stock trim, which increases ground clearance a bit for deep turns. If you're not concerned with leaning until the world tilts, you can use these instead:
https://www.shopbmwmotorcycle.com/products/avon-roadrider-sport-touring-140-80-17?variant=12734085103675&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&utm_campaign=gs-2018-10-28&utm_source=google&utm_medium=smart_campaign&gad_source=5&gclid=EAIaIQobChMInNLKtcPzhwMVls3CBB21GwjqEAQYBCABEgKpePD_BwE

as their lower, wider "70" profile will carry more weight, but these do lose about 3/4" clearance at max lean angles compared to the standard ones.

Don't fall prey to swapping out air filter components: the stock airbox is the finest design for this particular bike. The size of its air filter is more than 8x times as much as the engine can breathe, so there's no such thing as "restriction" in the air intake system of this bike - despite what internet lore seems to think nowadays. If you feel the need for more HP and don't mind revving to get it, look into the Megacycle 126-00 cam: you'll need a core cam to trade with them for it. It is the only current "high performance" cam out there that doesn't exceed the max lift rate for these valves. It WILL increase power, but it does so with about 1500-1800 more RPM to get it, as compared to the throttle you know now. When installing this cam, consider doing some port work, too: both will increase the breathing a bunch.

[Stev-o]

Less mass needs less brake.

How much less does a 550 weigh than a 750?

56lbs   [479 vs 423]

[Deltarider]

iKon totally has adjustable compression damping, so not sure what CalJ has seen.
...
I stand updated; Ikon does have a pair of “Dial-A-Ride” shocks for your bike that does have 3 preload settings and a 4 position damping knob. I’d not seen that upgraded shock before. At $475 it’s an awfully good value.

I have them on mine with the original name Koni. Frankly, I still don't know what the 4 position damping knob exactly does. If someone can teach me on this, I'm all ears. I'm 6.4 and weigh 88 kg.
Koni has always been Europe's first choice for shocks. In the 60s Mercedes-Benz and Porsche had them OEM. BTW, recently I learned that most parts for the German car industry are actually made in The Netherlands.

[WaxhawFive]

@HondaMan Last year I finished a long search for all of the bits needed to ditch the pods and install the original airbox.  It runs so much better now across the full rev range.  I don't feel I need more power in the twisties (although I do have a line on a 1980 650 motor that would make a fun winter project.)  So you are suggesting 18/18 if I choose to get some Excel Al. rims?  Your second link was a 17" rear, was that what you intended?

[M 750K6]

iKon totally has adjustable compression damping, so not sure what CalJ has seen.
...
I stand updated; Ikon does have a pair of “Dial-A-Ride” shocks for your bike that does have 3 preload settings and a 4 position damping knob. I’d not seen that upgraded shock before. At $475 it’s an awfully good value.

I have them on mine with the original name Koni. Frankly, I still don't know what the 4 position damping knob exactly does. If someone can teach me on this, I'm all ears. I'm 6.4 and weigh 88 kg.
Koni has always been Europe's first choice for shocks. In the 60s Mercedes-Benz and Porsche had them OEM. BTW, recently I learned that most parts for the German car industry are actually made in The Netherlands.

Think they're made in Oz now, branded 'Ikon'. I think Ohlins are still made in Europe.

Hagons are made in England (pre-load adjustment only, but built to your weight. I find them good for spirited road riding).

[HondaMan]

@HondaMan Last year I finished a long search for all of the bits needed to ditch the pods and install the original airbox.  It runs so much better now across the full rev range.  I don't feel I need more power in the twisties (although I do have a line on a 1980 650 motor that would make a fun winter project.)  So you are suggesting 18/18 if I choose to get some Excel Al. rims?  Your second link was a 17" rear, was that what you intended?

That's an "oops" if I had it tied to the 17" rim, size sorry!    Should be 18".

I suspect the 650's electrics will keep you a mite busy with that conversion. While the 650 makes HP almost like the 750, it is a lean-burn engine design. The lean-burn carbs that go with it are...put simply: a MAJOR pain to work with, and cold-idle/run is an experience all its own with that engine. I just spent 2 months untangling what a local 'vintage' shop did to someone's 650 here. It was all carb stuff, too, and the parts are hard to get, at best. All it had needed in the beginning was new float valves.

[HondaMan]

iKon totally has adjustable compression damping, so not sure what CalJ has seen.
...
I stand updated; Ikon does have a pair of “Dial-A-Ride” shocks for your bike that does have 3 preload settings and a 4 position damping knob. I’d not seen that upgraded shock before. At $475 it’s an awfully good value.

I have them on mine with the original name Koni. Frankly, I still don't know what the 4 position damping knob exactly does. If someone can teach me on this, I'm all ears. I'm 6.4 and weigh 88 kg.
Koni has always been Europe's first choice for shocks. In the 60s Mercedes-Benz and Porsche had them OEM. BTW, recently I learned that most parts for the German car industry are actually made in The Netherlands.

KONI was always my first racing choice, back when I did that stuff. I haven't been able to find their shocks to properly fit the 750 in a long time, though? Their too-long spring arrangement makes the spring hit the chainguard, bending it in against the chain. I have a set, don't know what to do with them: I think they are 10 years old, now? They are alos 0.25" or so too long, in their own recommended size for the CB750. Maybe for the 550 they have some that fit?

The ones I've used had adjustable REBOUND damping, but fixed COMPRESSION damping. This confused [us] for a while, so we ended up changing oil viscosity to get the compression damping we wanted, then set the ring for the rebound we wanted with that oil.

[Deltarider]

I still don't know what the 4 position damping knob exactly does. If someone can teach me on this, I'm all ears. I'm 6.4 and weigh 88 kg.

For your rear suspension, you need to set static sag by adjusting the preload washer. Unladen, measure the height of the seat frame to the center of the rear axle (finding two points that move under compression). Then, with your weight on the bike fully, take the same measurement again (you’ll need a second person obviously). The compressed height should be about 3/4” or 18-20mm. Adjust the preload scanner until you’re close.

For damping, ride the bike over some uneven surfaces intentionally. If the rebound is too fast, you will feel a “bucking” sensation because the shock is pushing the rear wheel back towards the road surface too quickly. If you feel a “wallowing” very sluggish sensation, then the rebound is set too slow (permitting the suspension to rest too long in a compressed state). You can adjust the damping so you feel the bumps occur “quickly” as if you’re shortening their duration without the bucking. That is optimal.

Why does it matter? Suspension is critical to proper traction. Traction aides in steering, handling and stopping obviously. If you’re rear wheel is too quickly rebounding, you’ve lost the merits of rear traction while under braking (weights shifts forward already due to front brake and front suspension compressing). And, under heavy acceleration, if the rear sags too much or too long, the front becomes unweighted and that is also not good.

You want the bike to sag evenly front to rear, and rebound equally front to to rear. You don’t want the bike to “pop” back up, but sag and rise smoothly. Far too many riders don’t pay any attention to setting up their suspension and that leads to handling problems, braking issues and crashes. If you rode two identical bikes with fully correct suspension for you on one of them compared to “stock” settings on the other, you’d immediately feel the difference. Confidence in steering, braking and handling are immensely different.

Suspension upgrades are, in my opinion, the single most important change one can make on a motorcycle. It improves every aspect of the bike’s performance from start-up to key off.

I still don't know what the 4 position damping knob exactly does. If someone can teach me on this, I'm all ears. I'm 6.4 and weigh 88 kg.

For your rear suspension, you need to set static sag by adjusting the preload washer. Unladen, measure the height of the seat frame to the center of the rear axle (finding two points that move under compression). Then, with your weight on the bike fully, take the same measurement again (you’ll need a second person obviously). The compressed height should be about 3/4” or 18-20mm. Adjust the preload scanner until you’re close.

For damping, ride the bike over some uneven surfaces intentionally. If the rebound is too fast, you will feel a “bucking” sensation because the shock is pushing the rear wheel back towards the road surface too quickly. If you feel a “wallowing” very sluggish sensation, then the rebound is set too slow (permitting the suspension to rest too long in a compressed state). You can adjust the damping so you feel the bumps occur “quickly” as if you’re shortening their duration without the bucking. That is optimal.

Why does it matter? Suspension is critical to proper traction. Traction aides in steering, handling and stopping obviously. If you’re rear wheel is too quickly rebounding, you’ve lost the merits of rear traction while under braking (weights shifts forward already due to front brake and front suspension compressing). And, under heavy acceleration, if the rear sags too much or too long, the front becomes unweighted and that is also not good.

You want the bike to sag evenly front to rear, and rebound equally front to to rear. You don’t want the bike to “pop” back up, but sag and rise smoothly. Far too many riders don’t pay any attention to setting up their suspension and that leads to handling problems, braking issues and crashes. If you rode two identical bikes with fully correct suspension for you on one of them compared to “stock” settings on the other, you’d immediately feel the difference. Confidence in steering, braking and handling are immensely different.

Suspension upgrades are, in my opinion, the single most important change one can make on a motorcycle. It improves every aspect of the bike’s performance from start-up to key off.

Thanks Calj. Well explained. I will check it.

[WaxhawFive]

The pricing for the suspension stuff is pretty reasonable; Race Tech gold valves - $230, springs - $150, rear shocks (adj) - $475, so $855 total.  Before I order this front suspension, these 35mm legs look kinda skinny.  Plus, if I'm thinking about 750 brakes, does it make sense to swap to a different front end at this point?  I would like to retain the original look with the rubber gaiters, so is there a worthwhile upgrade with larger tubes, better brake, and the stock look?  Or should I ditch the gaiters and go with early CBR front end?  I definitely want to keep a spoked wheel!  I know, this is the slippery slope.

[Mark1976]

The pricing for the suspension stuff is pretty reasonable; Race Tech gold valves - $230, springs - $150, rear shocks (adj) - $475, so $855 total.  Before I order this front suspension, these 35mm legs look kinda skinny.  Plus, if I'm thinking about 750 brakes, does it make sense to swap to a different front end at this point?  I would like to retain the original look with the rubber gaiters, so is there a worthwhile upgrade with larger tubes, better brake, and the stock look?  Or should I ditch the gaiters and go with early CBR front end?  I definitely want to keep a spoked wheel!  I know, this is the slippery slope.

Slippery slope? Get some ice skates ready…

The GL forks are 39mm, not sure about their length. But they are stiffer than the stock forks. I don’t know if I’d worry too much if you do the internal upgrades. A fork brace might be sufficient to keep what you have and feel better about it. Larger forks deserve a stronger, stiffer triple tree. The early model CBR600 forks are conventional and better, but then you open a can of worms about hub spacing, brake caliper mounting, etc. How far do you want to go?

My opinion, the upgrades you are considering with the stock forks are probably plenty good enough to improve the ride and enjoy the begeezus out of your bike. And it’s not so much money that if you change the front end later you will lose because you can sell the stock front end on to another rider.

   Best advice I've heard in a long time, and in today's world the stock front with upgrades can return your investment and then some if you were to change your mind and sell it down the road.

[seanbarney41]

+2...if you want to do CBR things, get one!  There are tons of them used and they are cheap (although I am seeing the nice ones holding value very strongly) and great bikes...but there is something special about old bikes, and that something is easy to lose track of if you are not careful.   

[scottly]

these 35mm legs look kinda skinny.  Plus, if I'm thinking about 750 brakes, does it make sense to swap to a different front end at this point?

The 750s also had 35mm fork tubes, including the twin disc F2/F3. Even the DOHC six cylinder CBX had 35mm tubes. The F0/F1 and K7/K8 calipers look just like the 550 calipers, if you want to maintain a stock look.

[WaxhawFive]

OK, yeah, I want to keep it like it is, that's the charm.  So no modern front suspension.  I'll look into what's needed to fit the larger 750 rotor.  Has anyone used the Rising Sun aluminum rims being sold by 4into1?  They are suspiciously inexpensive.  I would consider a 100 front tire on a stock size 19x1.85 rim, and a 110 rear tire on a 18x2.15 rim.  Also, is it possible to add a fork brace and keep the stock gaiters and fender? 

[scottly]

  I'll look into what's needed to fit the larger 750 rotor.

The 750 rotor and late K/early F calipers bolt straight on to your 550 wheel and forks; you only need the parts.

[Mark1976]

OK, yeah, I want to keep it like it is, that's the charm.  So no modern front suspension.  I'll look into what's needed to fit the larger 750 rotor.  Has anyone used the Rising Sun aluminum rims being sold by 4into1?  They are suspiciously inexpensive.  I would consider a 100 front tire on a stock size 19x1.85 rim, and a 110 rear tire on a 18x2.15 rim.  Also, is it possible to add a fork brace and keep the stock gaiters and fender?

   I've used these rims on and off for the last 4 or so yrs. On and off because 4into1 is about useless when you have issues with the products they sell. I did a 18" front wheel late last year using a Rising Sun rim and it was an absolute piece of garbage, 4into1 was indifferent about whether it was really a quality issue, as a result they in my s$#t list.
   I've had 4 or 5 sets that were fine, given the fact that ya get what ya pay for, but yeah, compared to a pair from Buchanan's, they're immensely less expensive. But then again, I've never had a bad rim from Buchanan's, but my wallet was always significantly lighter.

[scottly]

Just a note about aluminum rims; even though aluminum is 1/3rd the weight of steel, it needs to be thicker to have the same strength, so the weight savings isn't that much, like maybe 1 pound per rim.

[seanbarney41]

There are at least a few kinds and styles of fork brace that have been available over the years.  I don't know of any available brand new retail for these bikes anymore so if you find one available take what you can get.  There were sheet metal ones that attach where the fender mounts attach and function similar to the front fender brace, just sturdier.  There were also tubular steel ones that attach to the fender mounts.  Both these style may complicate stock fender and brake caliper mounting but don't interfere with the boots at all.  The best ones lock into the groove in the top of the fork leg provided for the boots, but then most provide an alternative groove for the boot...actually never saw one that didn't. 

Search for a thread on this site by Frank/754 on how to make your own fork brace that looks cool and functional but can be made using simple fab skills and materials.