Topic: MotoGPWerks Pipe CB550 (Jetting and video)

[goldarrow]

greg, i have the same setup as yours. 

UNI foam filter in stock air box
38 idle jets
105 main jets
needle clips at stock 4th notch
results:  rich and sooty at slow throttles

changed the needles to middle 3rd not
results: much better and no more blurbing or hesitation.  haven't yet pull the plugs, but feel a bit lean as i don't feel power on higher rpm and speed

what i have in mind and to do next, shim the needles so they are between 3rd and 4th notch.  basically half a step on the needle grooves

[gregripko]

Yep you've described the same exact experiences I've been having... The 38s work better than the 40s (40s produce poor performance and black deposits) while the 38s have a smoother ride but on a slightly lean result... Light popping but nothing major... It's kinda funny how sensitive the bike is with the pipe... And yet it sounds tough with a deep growl... So weird how such a suddle change in jetting can produce very opposite ends of the plug spectrum

[goldarrow]

http://i1061.photobucket.com/albums/t467/goldarrow/F46FEAE3-5D19-4E9E-BDC2-892D8AC87896-13237-000007842001F9C1_zps6de66696.mp4

Sounds badass, gold dude.   How's it run? Now I want one for my 550....

steve-o, get it when you can.  it is nice to be heard when riding in traffic.  i do commute a lot on my bikes and splitting lanes in this is awesome.  i rev my engine as i go through between cars in traffic, just to wake up the drivers at 7am and 5:30pm peak traffic hours   i'm bad, i know...lol

[gregripko]

Went from the 40s back to 38s and richness eliminated but mad popping from pipe... When plugs go from black and sooty to presumably lean can that mess a plug up to require replacement? When I pulled the plug you could see the white coming back on the plug... Like half and half after a 10 min ride...

[goldarrow]

i wouldn't worry about new set of plugs...i know these are cheap and only 10 bucks for 4, but if you have to change to new plugs every time you do this, could get really expensive. 

just to recap my settings, and finalize things up on my bike

76 cb550k 087A carbs
UNI foam filter stock air box
idle jets 38
main jets 105
needle clips 3rd notch
plugs 1, 2 and 3 look good, but 4 is way whiter than the others, so i think i found my lean condition - will double check the float height and call it done.

[Stev-o]

Be carecull of those white plugs guys, dont want to burn a hole in your pistons.

Gold dude - you got bigger balls than me, no lane splitting for me!  [no commuting either] I've been hit a couple times and been lucky.
Be careful Bud, your wife & kids need you.

[gregripko]

I have:

CB550K 1976
022A Carbs
#105 Mains
#38 Slows
Needle Position (middle.....runs lean with popping...going to go to the 4th position from top maybe)

Notes:

WOT pulls hard with no popping but has a bogging sorta bumbling in the 1/4 position... Lean condition maybe from needle? If keep that 1/4 position when riding it makes the bike run like poo and almost wants to die.... My stock position for the needle is 4th from top so I'll give that a try next to see if it relieves the stumbling/bubbling lag

[goldarrow]

Since we both are on the same boat here, so I say try 110 jets, and keep needle clips on 3rd notch, since this is easier than taking out the needles. 

I don't have 110 jets to try, might have to get some

[gregripko]

I'm going to ride it at these settings for a little bit as I think I had a small kink in the fuel line causing a lean condition.... The fuel line I bought is crap.... Not flexible enough... Here's a pic of my bike

[lucky]

Since we both are on the same boat here, so I say try 110 jets, and keep needle clips on 3rd notch, since this is easier than taking out the needles. 

I don't have 110 jets to try, might have to get some

"easier than taking out the needles"  To get it right you will have to ddeal with the needles. No way out.

[lucky]

I just keep hearing main jet-idle jet.....main jet -idle jet....main jet idle jet.

Too hard to deal with the needle? No mention of mixture screw adjustment when you hear popping at idle.

That one cylinder that is way different than the others must be addressed.
I would not even think about plug readings at this time.
I would focus on how it runs -thats all.

After it runs perfect THEN think about plug readings.
I would get it running right -ride it for a while and then one day take the plugs out and look at them after normal around town driving.
They will never look like new plugs out of a modern car with computer controlled fuel injection.

[gregripko]

Right as I crack the throttle after reviving down the road it sorta has this burble sound that is cleared by cracking the throttle more.... I pulled the plugs and they were dark.... :/ only the lightest crack of the throttle.... I'm running 38 slow with the needle in the 3rd position from top

022a carbs

[lucky]

Lucky, for future reference, you may want to add me to your list of people running 4-1 exhaust on otherwise stock cb550's.  I've got 40 idles, 105 mains, 1.25 turns on the air screw and needle in the middle.  There's pictures of my spark plugs (D7EA) on here somewhere after various throttle chops with these settings.  Everyone told me they looked alright.  Just fyi. 

Can you please tell me what year of CB550 since there are at least 4 different jet and needle combinations on the stock bikes?

[RFogelsong]

Lucky, for future reference, you may want to add me to your list of people running 4-1 exhaust on otherwise stock cb550's.  I've got 40 idles, 105 mains, 1.25 turns on the air screw and needle in the middle.  There's pictures of my spark plugs (D7EA) on here somewhere after various throttle chops with these settings.  Everyone told me they looked alright.  Just fyi. 

Can you please tell me what year of CB550 since there are at least 4 different jet and needle combinations on the stock bikes?

1975 cb550k - 022a carbs

Actually, I told you wrong on the needle height, it's the stock position which I believe is the 4th from top.  The last person that touched this adjustment (needle) was the Honda shop in Toledo 2.5 years ago, so I'm sure that all settings were stock except my stated mains (105) and air screws (1.25 turns out vs the stock 1.5). 

[RFogelsong]

Since we both are on the same boat here, so I say try 110 jets, and keep needle clips on 3rd notch, since this is easier than taking out the needles. 

I don't have 110 jets to try, might have to get some

"easier than taking out the needles"  To get it right you will have to ddeal with the needles. No way out.

Haha, yup, who is it on here that has a quote in their signature along the lines of "If it's wrong it's wrong, even if it helps ya'"?  Lucky's word is gold in my experience.  Even when I've thought I could rig stuff and shortcut it, 99% of the time, when lucky or twotired give advice, heed it. 

[goldarrow]

Since we both are on the same boat here, so I say try 110 jets, and keep needle clips on 3rd notch, since this is easier than taking out the needles. 

I don't have 110 jets to try, might have to get some

"easier than taking out the needles"  To get it right you will have to ddeal with the needles. No way out.

No argue here, and agree that needles need to be addressed, and will look into it eventually.   And if Lucky can tell us for sure, and absolutely sure that digging into the needles will fix the issues, I will get to it first.   

Settings at the moment. 
76 Cb550k 087a carbs
Uni foam filter in stock air box
38 idle jets
105 main jets
Clips 3rd notch
AF screws at 1.25 turns out

Slight hesitation at low speeds, transition to midrange is ok, feel weak power at high rpm

So definitely felt just tad rich at low speeds, definitely lean high speed

[TwoTired]

FYI, the needles can be changed on the bike without removing the carbs. I've done it.  A bit easier than removing the whole carb bank, and a LOT safer for rubber boot survival.  Takes about an hour, I recall.

[goldarrow]

FYI, the needles can be changed on the bike without removing the carbs. I've done it.  A bit easier than removing the whole carb bank, and a LOT safer for rubber boot survival.  Takes about an hour, I recall.

Yes. Thats how I do mine too.  About 1.5 hours as I go real easy on mine

[gregripko]

My settings are the following:

Cb550k 76

Main: 105
Slow: 38
Clip: Stock, 4th down from the top

It pulls really good WOT but crap in the mid and lower range...

I took the lid off my airbox and left the filter in (Uni foam filter) and it runs amazing... Should I just ride this way? Or should I change the slows to something lower than 38?

[Stev-o]

The slows are just for idle, I don't think that will help.
Their is an airbox mod that you should research, basically drill a few holes in it.

[gregripko]

I was thinking about sawing the snorkel off and just putting a new larger metal screen at the base

[gregripko]

I want to avoid modifying any stock parts if I can... I may even leave the snorkel on and put spacers (nuts) between the airbox body and the lid allowing a slit of air in

[Stev-o]

Totally understand, give that a shot and see how she runs. 

[gregripko]

Will do

[goldarrow]

My bike is blowing fuse still, so no updates