Topic: Am I running Rich or Lean?

[NastyNip]

Before anyone posts, yes I have read the FAQ. Yes I did search.

I can not come up with an absolute answer:

Bike in question: 1977 CB550F, in rough condition

My symptoms making me believe its rich are:

-bogging down when on the throttle
-engine works waaay better when cold
-wont return to idle unless I blip the throttle
-i have a moderately dirty airfilter (and can't find an element around here!)

BUT

symptoms for it being lean are:

-engine overheats, knocks, pings etc
-popping/backfiring through carbs
-when I remove the airfilter the bike is almost unridable (runs terrible, stutters) above 3500 rpm

I was reading the FAQ and it said that if its rich the acceleration will "feel" slow. I know its difficult to convey this concept over the internet, but how do I know that my throttle 'feels' slow?

Also, it said to turn off the fuel and run it. Well, today I accidentally started and was running my bike with the petcock in 'off' and took off down the street...   I noticed the bike performing poorly and would stumble when I got on the throttle... This is normal right? Not determinate of Rich/Lean, correct?

A major thing that I don't know if this correlates to mixture, but sucks, is that whenever I'm running higher (4k+) RPMs and let off the throttle a little bit (For example, slowing for a stopsign), the bike lurches and surges for a moment before decelerating. Thoughts?

TIA

Cheers

 

[neil10]

check colour plugs dark rich whitish lean

[OldSchool_IsCool]

If it "feels" like you are guna slide off the seat and you have to squeeze down with your thighs to hold on, then your acceleration is not slow! 

[gerhed]

Probably more than one thing going on here but,
if it starts well and revs good when in neutral
and then bogs down when in gear and on the gas--
I'd say it's running lean.

[beta1042]

As for the needing to "blip the throttle", try lubing your control cables.  Friction in your lines or at pivot points could be causing unnecessary resistance leading to the throttle not returning to its stop.

[mlinder]

Plug chop. You need to do this. I'm guessing that each plug will look very different from the others.

[WFO]

I would start by getting a clean filter then do a plug chop as mlinder suggested to find out what your next move should be.

[TwoTired]

Are you really asking for advice regarding tuning the engine to a Dirty air filter?
If you can't find the stock type, then get a UNI NU-4055 foam filter along with the filter oil and cleaner.

The spark plug deposits are your window into the combustion chamber.  They will tell you if you are running rich or lean.
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

Before you worry much about running rich or lean...
Adjust the tappets
clean /gap the spark plugs to "as new" condition.
Check point gap
check timing
Check spark advancer operation or the the mechanism is moving freely.
AIR FILTER!!!  (Like, how would you like to breathe through a 1/4 inch hose and run a marathon?)
Make sure all the head pipes have about the same heat.

Or, in other words, do the routine 3000 mile tuneup per Honda specification.

Learn what position the Idle air bleeds are set at.  (number of turns out from the lightly seated)

Cheers,

[Duke McDukiedook]

Like TT said, give it a full tune-up first, then you can look at your carburetor.
Get those ducks in a row and pluck it off.
Put new plugs in after you tune-up and then you can analyze it. The plugs will tell you what's going on, listen to them.