Topic: Off-idle hesitation

[NickC]

1975 CB550k
Uni foam air filter, 4-1 exhaust, dyna 5ohm coils, dyna S ignition
Carbs are as  clean as possible, needles in stock position, stock jets.
New plugs, tappets adjusted, timing set, carbs synched.

Idles awesome and has nice crisp throttle response. However, if I'm putting along in say 1st or second gear, it bumps and jumps a little bit until i get some higher rpms. Sometimes there's a hesitation also if i go wide open acceleration. Once I'm accelerating/WOT it runs awesome.
My number 4 exhaust pipe is definitely colder than the other three, with number 3 being warmer, and 1&2 f'in hot!
Suggestions?

[TwoTired]

I'd figure out why the pipes aren't evenly hot.

Check your slow/idle/pilot jets for blockage.

What have you set the air bleed screws at?

Look st the spark plug deposits.  If you find a lot of black soot on the center electrode insulators, you have carbon fouling, causing intermittent spark.

Cheers,

[NickC]

Screws are 2 turns from seated. Would plug condition after idling tell me anything, or would a plug chop be better?

[Bido]

I had that off idle problem on my 78 750 I raised the needles one notch or one washer I don't know what the 550 carbs are like and that solved the problem. Be sure that everything is clean and set correctly first.

Good Luck
Bido

[TwoTired]

Why two tuns out? These are air bleeds turning them out too far make the low end hesitation under load, worse.
You don't have an accelerator pump like the 77-78 750's do.

Your bike modified from stock?

If you have an idle problem, look at the plugs after idling.


Cheers,

[TwoTired]

You still need to get all cylinders working the same before fine tuning carbs.
Cheers,

[NickC]

Why two tuns out? These are air bleeds turning them out too far make the low end hesitation under load, worse.
You don't have an accelerator pump like the 77-78 750's do.

Your bike modified from stock?

If you have an idle problem, look at the plugs after idling.


Cheers,

Clymer manual said 1.5-2 turns out, how far should the be? Only mods are 4-1 exhaust, dyna 5 ohm coils, dyna-s ignition

[TwoTired]

Clymer manual said 1.5-2 turns out, how far should the be? Only mods are 4-1 exhaust, dyna 5 ohm coils, dyna-s ignition

Honda Shop manual (download-able from the this site) say 1 1/2 +/- 3/8.

A more open exhaust with less back pressure than stock would tend to require a richer fuel setting on the carbs.  Those screws are air bleeds.

Cheers,