new cb77 owner. running/idle issues

apophis · Post by **apophis** » Sat Oct 20, 2012 7:14 pm

I am not new to honda twins, just 305's. I have a recently purchased 64 cb77.

Here is what I have done since purchase.
1. drained and cleaned tank and petcock and rubuilt petcock
2. new plugs
3. new points
4. nw condenser
5. new battery
6. new fuel line

so today I fully cleaned the carbs so they were spotless and all passeges were clean.

I adjusted the carb cables so the slides moved at the same time.

my issue is when I throttle, in any gear, ity takes almost 10 seconds to return to a lower rpm. It even raises when I pull the clutch except when in neutral. so if I am at 5000 rpms in 2nd, pull the cllutch, it goes to 6000, i put it in gear, and the bike doesnt slow down with 0 throttle for a loooong time. When I pulled the air cleaneds off and checked the slides, they snap down with no issues.

also today I static time the bike with a bulb to "F" , then "TF". it ran better, but if I follow the carb adjustment for the air screws, the bike dies regardless of if the idle scres are in 100%. the bike will not run with 1-1/8 or 1-1/2 turns out. It seems to run best if the air screws are out just 1/2 turn.

Note: I live at 6,000 feet above sea level, but the bike has always been in colorado.

I have a main 135 and idle 42 in both

the bike accelerates great. it just wont decelerate quickly.

I even tried stretching the carb springs which did nothing.
It is loike the bike idles great, but if you even give a hair of throttle it jumps a lot. I already checked the required end play of the cables and I have the 1/8" or freeplay in the throttle.
not sure what to try tomorrow...

Hahnda · Post by **Hahnda** » Sat Oct 20, 2012 9:17 pm

You may have a problem with the spark advance.

apophis · Post by **apophis** » Sun Oct 21, 2012 11:50 am

i will recheck the timing today. the process i used was "ed moore's special tuning recipe"

apophis · Post by **apophis** » Sun Oct 21, 2012 5:51 pm

1. is the spark advance in the middle of the cam and not on the end by the advancer plate. the diagrams in my manual suck

2. I have 135 mains, BUT, I live at 6000 feet above sea level (colorado). when I look at what jets I should have, the forum says 120-125 based on altitude. When I do the choke test, with the 135 jets and sing the lowest needle setting (most fuel), i do not bog at 1/2 choke, nor does the engine improve. it does nothing. I only bog at ~95% full choke.

I assume this means I am lean even though I live at high altitude.

davomoto · Post by **davomoto** » Mon Oct 22, 2012 7:40 am

Have you adjusted valves? Checked for air leaks at intake manifolds? Are you sure carbs slides are properly synced?

Davo

apophis · Post by **apophis** » Mon Oct 22, 2012 12:21 pm

valves were cold adjusted to .004

I have new seals on the both the carb to insulator and insulator to head. I would hope there were no leaks. I did finger tight + 1/8 turn by wrench

I had a new throttle cable and installed it on sunday. made sure both slides bottomed out, had the slide cutaway facing he back of the bike and that both started at the exact same time. I had the tank off during this process to watch the slides as well.

FluteTears · Post by **FluteTears** » Mon Oct 22, 2012 2:12 pm

I had the same problem on my 305 dream with a new cable I just did not think that cable was the problem so I kept after this and that then I decided to lube the new cable. Problem solved. Just a thought.