Topic: Cb550f 069's and pods experience

[kerryb]

I bought a 77 550f to have a bike to ride for a short stay in  florida.  It had not run in 4 years and did not have any airbox components.  To save time and money just to get it on the road, I put emgo? pods on it.  I didn't expect much from it but it rides pretty good.  Will put stock airbox on in 1-2 months.
069 carbs, 98 mains (keyster), 38 idle jets (keyster), stock keihin needles w/ clip 4th position from top.  Clear tube test bowl levels 2-3mm from bowl seam.  Mixture screws 2 1/2 turns out. Three turns out on mixture screws yeilded loss of power at 4500 rpm.  Spark plugs are NGK D7-EA.
Issues:  runs rich at idle (I think because of fouled plugs)  engines struggles off-idle and with small throttle movement in 1/4 range.  Pops and burbles on deceleration from higher revs.  Idles smooth after warmup but has hanging idle with no air leaks at boots (spray test on boots.  Aborted higher speed plug chop (petcock issues) showed  clean burn at 4-5k rpm for 3 miles at 1/4-1/2 throttle (no hills in florida).
Runs very strong at 1/4 to wot, but struggles with small increases in throttle.  Responds very well to rapid/ larger throttle opening movement.
The pods have no bellmouth shape at all!  Is there a test to perform that might yeild cleaner plugs at low rpms?  I have a long drive at 20 mph to get to higher speed limit. 
Am I stuck with this poor performance for now or is there a way to improve burn and acceleration at low throttle openings.  I have several sets of plugs to perform more plug chops, which chops should come next?  Would raising the needle clip position be a good experiment?  At groove #4 from top now.
I know its the pods, and appreciate your indulgence of this folly.

[kerryb]

Almost forgot,  stock "f" style 4 into 1 header and stockish muffler with baffle.  Static timing is now spot on with proper points gap.  Carbs are synchronized with vac gauges.  Advancer is in good condition and appears to be working but my timing light is on strike this week.

[dave500]

im running 100/40 in 069a carbs on a 550 with stock airbox and decent 4/1 pipe,dont mess with plug chops a #$%*ing waste of time just get the proper airbox on it.

[kerryb]

im running 100/40 in 069a carbs on a 550 with stock airbox and decent 4/1 pipe,dont mess with plug chops a #$%*ing waste of time just get the proper airbox on it.

I agree, stock airbox required, I'll bring one with me for the next riding season here.  To finish this one (3 weeks) I'll keep trying to tune for pods so I can go more than 150 miles without having to cean the plugs.
Without a plug reading, how did you determine 40's and 100's were better than the specified 38's and 98's?
I'll try dropping the needles one notch, but then need to make sure I'm not running too lean at 1/2 throttle, so unless there is another way I'll have to waste my #$%*ing time doing a plug chop.
always an adventure...

[dave500]

I tuned it seat of pants,more plug hole threads get stripped pulling plugs over and over?check your caps resistance aswell,you got the ignition spot on with a dwell meter and timing light?if not your wasting you time even more.

[Deltarider]

I'm with Dave in his advice to abstain from plug chops. For quite some time it has been a popular chore in this forum. Those in favor substantiated the procedure with wisdom from books. It's a waste of time imo, no matter what diagram is presented. Although these diagrams usually do warn the systems overlap, this seems the first folks tend to forget. What goes on in the combustion chambers may be far more chaotic than these sterile pics suggest, especially under acceleration. Nowadays we're used to digital accuracy with many things, but let's not forget that, seen in evolutionary respect, our type of engine is just the next step after... the steam engine. Sparkplugs on our CBs are not in a particularly friendly spot to pull them. There's always the risk of damaging the porcelain and/or the thread. As far as CB350/400/500/550, start from prescribed settings. Fine tuning an airscrew and - when intake has been altered - changing a main jet is as far as I would go.

[kerryb]

Ok, thanks guys, I 'll put the needles up one notch, turn the the screws back in some, and see how long it takes to foul the plugs again or hole a piston.  Having ruined a plug hole in a volkswagen head in my youth, I'm quite good at pulling the plugs without stress to them or burns to me.  It's all about where you stick your fingers!

and the adventure continues...

[dave500]

so the ignition is spot on then?

[kerryb]

As good as you can get without a timing light.

[Deltarider]

As good as you can get without a timing light.

Are you aware that in our wasted spark ignition there is polarity to observe, in other words: did you try flip the inductive clamp?

[Tracksnblades1]

As good as you can get without a timing light.

Are you aware that in our wasted spark ignition there is polarity to observe, in other words: did you try flip the inductive clamp?

You could just use the other plug wire in the (wsi) pair for the opposite polarity...

[Tracksnblades1]

Kerry b,

Uksparky had a bog hesitation problem on the forum not long ago.
In his case, if I remember correctly, he found a overly rich condition,causing the bog.
He would use an uphill grade to help diagnosis the condition.

A quick throttle opening on non-accerator pump carburetors can create a lean bog at lower RPMs....
Some will apply a little choke at bog speed to determine if carbs are lean....

[Bankerdanny]

A couple thoughts. (1) You likely need a richer jets and (2) Keyster jets suck and are notorious for not being the size they say they are. You can get actual Keihin jets from jetsrus.com.

I recommend ordering a set of sotck mains and slows and then a couple richer sets of mains. The one upside to pods is that they make it super easy to get the carbs on and off to swap jets.

[kerryb]

Delta,   Did not know or remember about the ignition polarity thing with induction clamp, will try to look at that.  The induction clamp is whats broke with my timing light, too bad I grabbed the wrong one when packing my tools. 

T's & B's;  I don't know yet how to interpret my symptoms but will try the choke thing.  Symptoms are; very small throttle  changes yeild a bog, very large sudden changes yeild wonderfull power!  (Whack the throttle open and all is good!)  Just to keep it interesting, there are no hills within 200 miles of me, my goodness, Florida is really flat!  Luckily, there are many places nearby where I can go wot for a mile or so to do checking, but it seems pointless because it runs best at wot.

Bankerdanny:  I jets-r-us is reporting that genuine keihin jets are not made/available anymore, so I guess I have to look elsewhere for the brass I want.

To all:  I started this process with the needle clips two notches richer than the stock specs call for.  Am I missing something if I think this is part of the problem?  My plan is to go out tonight and move the clips up one notch and go for a nice ride tomorrow.  I've been reluctant to do this earlier because so much has to be dissassembled to do it, but it just seems the obvious next step to reduce the air fuel ratio. But then...what about the mixture screw?, leave 'em alone (at 2 1/2 turns out)?

...this is fun but...I sure am looking forward to a real airbox!

[Tracksnblades1]

Kerry,

The choke thing can be similar to a cold chainsaw or small engine resisting to run smooth or accept more throttle without bogging unless the choke is partially on.

 While being very careful and choosing a deserted road, you could accelerate purposely causing the bog situation you described and lightly apply the choke to see if it corrects the condition (makes the engine take off and accelerate) or makes it worse.

Your 550 carburetors should not have an accelerator pump, unless I'm wrong. The reason I brought this up is because an accelerator pump shoots a shot of gas into the carbs (intake) instantly enriching the mixture so the engine won't  bog during sudden or large thottle openings. Which would commonly cause a momentary lean condition. Since you are experiencing a good running engine during your quick throttle transitions, without an accelerator pump in the circuit, you may be experiencing the same too rich condition UKsparky had posted about in the recent past.

The non Keihin jets are known to cause baseline jetting problems across the sohc engines.

[dave500]

try and find genuine jets even if used,keyster really do suck,i had one stamped 100 but a brand new 1mm drill bit wouldnt pass through it,the same bit on a genuine 100 was like a precision bush!the slow jets need to be precision because they are so small,heres a brand new keyster slow jet for you.

[flatlander]

i get this on jets-r-us:
https://www.jetsrus.com/a_jet_kit_street/honda_550_CB550F_1976.html

are these not real keihin?

[kerryb]

i get this on jets-r-us:
https://www.jetsrus.com/a_jet_kit_street/honda_550_CB550F_1976.html

are these not real keihin?

Those certainly look real, and I would like to be able to find that listing (showing year and model) for myself.
I have imposter slow jets, main jets, and main jet emulsion tubes.  The PO's even included the keyster box and sales reciept (over $110) but alas, they only left the genuine needles.
When I try to find main jets, I get this notice;  These jets are no longer produced by Keihin so it is not possible to get them in GENUINE. If anyone is selling them as GENUINE be extremely cautious as they are probably counterfeit.

 So I guess I'll be looking for used main jets that haven't been tampered with.  Anybody want to part with your now "sought after" untampered main jets in size 98 and 100 for a set of 069a carbs? (for a reasonable price!)

[Bodi]

"Seat of pants" tuning has melted many pistons and fouled more plugs.
Yes, pods are a PITA to tune for, the stock airbox assembly with a stock or aftermarket filter and stock (genuine Keihin) jetting is easiest and usually best. Some bikes, even all stock, need some tuning help due to overly lean jetting for emissions compliance.
Pods are not always a "performance" upgrade (illusory as that may be) but often a styling choice. Pod threads get political/religious in short order... if you want to run pods, tuning can get the engine running well but they are NOT just "bolt on and go".
Plug chops are a great way to tune carbs and, before EGA dynos, the only way. The process is easy to mess up though. It must be done in order, from WOT down through 3/4 - 1/2 - 1/4 throttle etc. You can't correct for a lean/rich main jet with needle position changes.
If you can't change plugs without stripping the head threads... you really should stick to a hobby less challenging.
If you can get it on a dyno with EGA you can do a lot better of course, but dyno time is not cheap and most of your time will be swapping jets and adjusting/modifying needles.
Regardless of how you go about tuning the carbs, through much experience you will become adept at getting the stack off and on.

[kerryb]

Over the years I have read so many posts about needle clip position that it makes me think they are an important factor.  Upon advice from counsul, I started with my clips in the fouth position from top  "just to get it running" and the air screws out 3 turns. (Thanks Bomberman!).  A few hundred road miles and plug cleanings revealed 2 1/2 turns out for the air (mixture) screws and It runs really good when the plugs are clean.  Even the hesitation is minimal.
So turning the air screws really does make a difference...to my amazement! 
Against no ones' advice or counsul, I took it all apart last night (way easier without that silly airbox in the way) to change the needle clips up one position to #3 from the top.   Wa, wa, waite a minute...isn't all this nonsense because I DON'T have an airbox?  Oh, yeah, they did say that!  I'll have to put one on as soon as I get  "real" jets, I mean genuine keihin jets, not "seeeears" jets! (thank you mr. Zappa!)
Today, when time permits, I'll re-synch the carbs ( they sound just a touch "off" at 5k rpm), and try to convince the timing light to flash on command.  And see if there is enough wire left to trim the ignition wires one more 1/4".  Then, if the rain holds off, take it out and ride like hell, (or tool up and down the street at 20 mph!), and report my findings.

Edit:  Bodi posted his jet advice while I was checking speling on this one.  Looks like 100 mains are in order to go with my needle change.

[kerryb]

I'm gonna have to go for advanced butt training because it still feels great, "whack the throttle and all is good!  This after my initial disappointment  at loss of power when I  open it up, anything over 3k rpm showed loss of power.  Pull over after 2 miles to turn the air screws in and curse myself for leaving the choke at 1/2 from warmup.
So now...it runs fabulous, lots of power, but my butt can't tell the difference.  No point in trying to read the plugs 'cause I spoiled any possibility of credible results!  Went home because rain looked immenant, pulled 1 plug and of course it was all sooty, darn!
The bog at small changes seems better, but it's still there.  Played with the choke going into a stiff headwind but couldn't decide if a little choke helped any, seemed to hurt more than help.
I'll focus my attention on the timing light till another ride opportunity presents itself.

tomorrow is another day, another chance to foul the plugs... ( going to be a bummer going back to snow)

[Deltarider]

... pulled 1 plug and of course it was all sooty, darn!

Look at the 'nose', the ceramic part in the centre (which is white when new). It's not unusual that the thread's end is a kind of sooty.

[dave500]

seat of pants tuning is fine if your savvy,with stock airbox and 100/40 i couldnt go wrong?id forget about 98 jets kerry even with stock airbox,be sure you check your caps,if you havent checked the resistance and its gone high you WILL foul plugs,over the years ive barked on about getting your ignition spot on before you #$%* with carbs!!it still applies now!!,if you think your ignition is good enough youll pull those jets and carbs forever #$%*ing believe me,get it #$%*ing spot on,start with those caps resistance check,then ditch those points and install an electronic ignition,be smart.

index the tdc mark,its always wrong a coupla degrees either way,that pin hole aint real precision,find true tdc with a stopper and align or remark the case.

spend a little time on detail,those emulsion tubes,chamfer the bleed holes a little,do it to the slow jets bleed holes aswell,if you have airscrews with holes,get solid ones or solder them up,youll get more control over the slow speed and transition to high speed,i find the middle slot for the needle is fine,too many guys chase their tail on this #$%*.

[dave500]

heres a 550 motor im tinkering with now,was a non runner,went over carbs,still has points,not bad response and idle,no filters at all.

[Deltarider]

Responses nicely, be it from a raised idle. The yellow marker stuff on the sync adjusters indicates they have not been tampered with a lot, which is a good thing. I envy the solid casing of that timing light.