Topic: 022a is better than 069a

[NewGuy]

Hello all!

I'm a very long time lurker, and I just registered because I was not able to resolve a question (for the first time). Let me start by saying that I think your group is an outstanding resource and I've been a regular visitor; especially when I was rebuilding my wife's CB350F.

Please pardon the inflammatory thread title; but this is exactly the discussion I was hoping to start.  I've got a project underway whereby I'm putting a non original motor into a '77 CB550K.  The motor is CB550E-1139641 and originally carried the 069A carbs.  Unfortunately one of the carbs has some internal damage, so I was going to use the carbs from the original motor (CB550E-2002706).  I think the carbs from the original motor are 022A, but I can't seem to find a stamping on them, other than "PD" and the location number.

My question is a two parter: how can I confirm that these really are 022A's?  And, is there any reason not to use them in place of the 067A's?

The 022A's (if these are why I have) seem to be preferable for Pre-EPA'ness, and the extra tuning flexibility.  Plus to my eye, they are prettier. 

I plan to run pods and MAC 4-1 exhaust.

Thanks in advance!

[TwoTired]

With pods and a noisy, loud exhaust (low pressure), you will have to rejet any carb selection you make, as the carb set up numbers match the stock induction and exhaust system used.  All the Cb550 engines have the same internals, power, and ratings.

PD carbs are NOT 022A equivalent set up numbers.  Just above the bowl interface, you'll see numbers stamped  in the carb body. PD46 something.  Standard for the CB550K in 77.  These have manifolds that don't have vacuum ports for syncing, as the ports are available on the carb bodies.  PD carbs also have a cable operated choke.
The 069A (stamped on the echa caby body mount flange)was the carb setup (refers to internal jetting and adjustment selections) used on the CB550F models (all).  The manifolds for these do have port plugs for vacuum syncing, as the carbs don't have such a feature.  Choke is a levr on the side of the carbs.

Between these two carbs, which operate in exactly the same way, apart from a variation in the pilot circuit, there is no power difference once set up for the exhaust and induction selected.

Neither is "better" than the other.  The PDs will need a choke cable, which some find convenient.  As the earlier style was made in higher numbers, parts do seem more available for them than the PDs.  But, after market parts are a crap shoot in quality and dimensional adherence to stock components, as well as within brand.  Keihin parts are better regarding quality a part dimensional tolerances.


The 069A carbs are "sloppier" and allow the engine to run with less precise tuning. The PDs can be tuned for all around performance, power, mileage, and driveability.  Both will require skill and knowledge to operate properly with pods and pipe changes.

[NewGuy]

TwoTired,

Thanks for your reply.

I know I'll have a length battle ahead of be getting the carbs dialed in.  The barrier at this point is locating the appropriate carb rebuild kit for the PD's.  And, of course, getting an assortment of jets and needles to aid the tuning effort.

Can you point me in the right direction?

Thanks,
NG

[TwoTired]

You might try Jetrus.

imo, it's hard enough to get the stock parts for a 35+ year old bike.  You will need custom needles and mains.   Good luck!

[NewGuy]

Yikes!

So what is the best way to handle that?  Get a handful of stock jets and a set of jet drills?

I'm getting the distinct impression that you don't endorse the kind of modifications I'm proposing.

...that might imply that the best way to approach this would be to get some more modern aftermarket carbs and retrofit them.  Or would that be inviting still more heartache?

Thanks for your input.

[TwoTired]

You don't say why you want to run pods and a mac 4-1 on a stock engine.  Is this an art project?  Or, do you want a functional, versatile, no headache, everyday rider?

Pods aren't anywhere close to ideal for a street bike.  OK for a race bike with limited throttle position operation.
The Mac 4 into 1 is in no way a performance exhaust, unless by performance, the goal is it keeps you legal for the minimum cash outlay.

The main jets shouldn't be too hard to get in various sizes.   I don't favor drilling for a street bike.  OK for a track only bike.  Even the pilot circuit won't be too much challenge.   It's the jet needle and it's profile that can be quite a challenge to get right, especially with pods injecting turbulence directly into the carb mouth, and turbulence varies with the velocity.

Do you have access to a Dyno or a test track that allows full power/ full load operation?  What method will you employ for tuning purposes?


No, I don't favor pods which throw away multi-thousands in development costs for a good all around performing induction system, in favor of a $9.95 barely engineered eye wash, that might have a small marginal benefit at or above red line RPM (depending on brand selected).

[Tews19]

I'm with TT! I bought k&n pods for my 550 bored to 605. I put them on last night. They were loud and the bike hesitated upon giving throttle. I removed them this AM and put on the stock airbox. No more hesitation.

[ekpent]

Yikes!

So what is the best way to handle that?  Get a handful of stock jets and a set of jet drills?

I'm getting the distinct impression that you don't endorse the kind of modifications I'm proposing.

...that might imply that the best way to approach this would be to get some more modern aftermarket carbs and retrofit them.  Or would that be inviting still more heartache?

Thanks for your input.

Do a search and you will see pods can be a little bit of a controversial thread. Does not rank as high as oil but sometimes worthy of a little batch of popcorn.   

[Tews19]

New guy I have those k&n pods and.if you want them I let them go for a smoking deal! I'm mean smoking!  Pm me if interested

[Duanob]

People should realize that PODs are for looks only. High maintenance looks at that.

[NewGuy]

Thanks to everyone for their input.   I'm building a brat-style bike and want to keep is as light, lean, and "empty" as possible. This was the motivation behind pods.

That said, I'm an engineer by trade and deplore any occasion where function is compromised solely for appearance.  For appearance, extra packaging room, and reduced weight..... that's a more compelling value proposition. 

Let's set that issue aside for now, and just say that the intent is to run non-stock induction and exhaust.  This means I'll need options for jetting.  How do I give myself those options?  Are there a variety of main jets and needles available for the PD carbs?  Or should I change direction and go to the 069A's?   

If jets and needles are around- who has them?

The last thing I want to do is invest many hours on building this thing to have an unrideable lump at the end of it.

[CoachDoc]

I ran 022 carbs with a Mac 4-1 exhaust for a while on my '74 550 and it ran flawlessly with the stock carb setup and stock air box. Eventually I bought a new set of stock pipes and when I installed them there was no improvement in performance or fuel economy. Bottom line is this- use the 022's with your Mac 4-1 and don't worry about rejetting.........you'll be fine, BUT forget the pods and use the stock air box. Pods are more trouble than they're worth.

[KiefRichards]

I ran 022 carbs with a Mac 4-1 exhaust for a while on my '74 550 and it ran flawlessly with the stock carb setup and stock air box. Eventually I bought a new set of stock pipes and when I installed them there was no improvement in performance or fuel economy. Bottom line is this- use the 022's with your Mac 4-1 and don't worry about rejetting.........you'll be fine, BUT forget the pods and use the stock air box. Pods are more trouble than they're worth.

...but, he's an engineer. And imagine the benefits of losing that heavy 3lb airbox. Also, he can "pack" stuff in the empty airbox spot in the frame.

[NewGuy]

CoachDoc- thanks for your suggestions.  That's very helpful!

I'm getting the picture that pods are ill-advised.  Would velocity stacks or the "Anti-pod" be better suited?  I'm really after that sparse-as-can be aesthetic, but she needs to be rideable.

[TwoTired]

Form follows function, in my experience.

Ever see any production bikes where the engineers fitted them with open velocity stacks?  Ingest a few bugs, sand, and dirt, and you'll have warranty issues.
The stock induction system did put velo stack right on the carb inlets...inside the induction system.
The Velo stacks seen at the track, are put on engines that see frequent rebuilds.  Is that the dynamic you long for?

I'll let others relate experiences with the anti-pod, as I've not invested in that approach.   But, I'm pretty certain it will still need jetting adjustments

I'll ask again.
Do you have access to a Dyno or a test track that allows full power/ full load operation?  What method will you employ for tuning purposes?

If not, the stock jetting has been tried and true for reliability and street operation.  ...which was selected for and coordinated with the stock induction system.

[Bankerdanny]

Even if you can find different needles, the challenge is getting data on the profile. For the SU's on my MGB there is an Excel based program that allows me to input various needle numbers and see graphically how the richness profile changes across the throttle opening. I don't know if anything that usefull exists for the Keihein carbs.

Based on the many jetting threads I have seen here it appears that jet changes are the only things that can be easily quantified as the jet numbers correspond to orifice size.

[Duanob]

Thanks to everyone for their input.   I'm building a brat-style bike and want to keep is as light, lean, and "empty" as possible. This was the motivation behind pods.

That said, I'm an engineer by trade and deplore any occasion where function is compromised solely for appearance.  For appearance, extra packaging room, and reduced weight..... that's a more compelling value proposition. 

Let's set that issue aside for now, and just say that the intent is to run non-stock induction and exhaust.  This means I'll need options for jetting.  How do I give myself those options?  Are there a variety of main jets and needles available for the PD carbs?  Or should I change direction and go to the 069A's?   

If jets and needles are around- who has them?

The last thing I want to do is invest many hours on building this thing to have an unrideable lump at the end of it.

Honest opinion? I would go with the 069As and a 4 to 1 exhaust since that's the F model supersport set up. My F model seemed to have more get up and go than my K model. I attribute that to fuel flow set up with everything else being equal (engine, size, weight, gearing, etc.)

[NewGuy]

TwoTired:

No- I don't have access to a dyno.  My plan was to use throttle chops, a long stretch of country road, and a box of virgin spark plugs.  I have some motor tuning experience so I think I can struggle through it; so long as I can find jets! 

While I appreciate your input going back to the stock air box is not an option I'm considering.   

What I'm after is the optimal compromise:  Something that will run well (if perhaps not ideal) but still meet the aesthetic goals.  This would not be my daily rider (I have other bikes to choose from for that).  I can live with a some minor fueling issues..... but only minor.

If velocity stacks give the carbs the clean airflow they crave, but also allow me to keep that clean look- then perfect. 

Surely this is not impossible, there are a great many people who do it!

[Duanob]

Surely this is not impossible, there are a great many people who do it!

And there are a great many people that have problems getting their SOHC4s to run correctly too. Just search this board.

[TwoTired]

If velocity stacks give the carbs the clean airflow they crave, but also allow me to keep that clean look- then perfect. 

Your right, it's a cheap old bike with parts easily obtained for rebuilding the top end.   
Or, perhaps you will only operate the engine on clean air days?

Surely this is not impossible, there are a great many people who do it!

Ah the existence proof argument.      Which assumes the testimonials of success from others are based on a comparison to how the stock bike operates.  Or, that the foibles introduced by the mods were overlooked, understated and/or sold off to someone else without mention.   Who cares if you can never tune for proper operation at exactly 2/3 throttle.  Just how often do you need that?

Anyway, there are lot's of examples of bad behavior AND bad designs.  Doesn't mean it should be replicated.  I suppose the very definition of a brat bike is one that operates (mostly) in the face of reason.  Safety and utility be damned!

Whatever.  You will do what you want, and may learn something in the process, which has value in itself.  I just recommend you don't make a change that is irreversible. Or, you'll need a patsy to take it off your hands or a bunch of parts to sell off later.

I'm fairly certain I'm not going to sway you from your artistic goals of form over function.  Just don't say later on that the SOHC4 is a piece of #$%* because it just won't run right.

Good luck on your quest!

Qapla'