Vintage and Classic Hondas

cb750c dohc carbs problem

_‹ Previous Topic Next Topic _›

Classic

List

Threaded

4 messages Options

petros88

cb750c dohc carbs problem

Hello to all new to the forum take it easy on me... recently i customise my cb750c dohc to brat syle... i remove the air filter (yes i know good luck to me with the carbs)and i add some high quality pod filters by DNA.. well now i am facing a problem... when i start the bike is idle great BUT when i am opening the throttle the rpm stay high for about 10 second then drop to normal... carbs are clean with ultrasonic... and compress air and carb cleaner... bench synch and the synch using a manometer on the bike.... i add bigger jets on the carb but the problem is still there.(assume that after putting pods they need more fuel) .. i also check for vacuum leaks no luck either...

any ideas please regarding by problem is well appreciate ..

p.s my timing is correct..

petros88

Re: cb750c dohc carbs problem

TOOLS1

Re: cb750c dohc carbs problem

Administrator

In reply to this post by petros88

Bike looks good. It sure sounds like a vacuum leak. Pods do not usually effect idle. I use starting fluid to find vacuum leaks. Carb and brake clean do not do the job. I have found vacuum leaks around the fuel/pilot screws. Practically every set of carbs I take apart is missing the little O-rings and washers on them.
TOOLS

Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)

petros88

Re: cb750c dohc carbs problem

Thank you Tools for your response.. i will go tomorrow and by some starter fluid to check again ... i am pretty sure that I included the small o ring and washer.. i am going to check for vacuum leak again and post the results ..i was working on the bike earlier and decide to start it with out the pod filters and idle was returning back to normal for some weird reason... i am thinking that i am running too rich at the end of the day.... running with pods idle hangs up for seconds when i am turning the throttle ... remove pods indle back to normal when turning the throttle..
next after the starter fluid check i will close the mixture screw back to 1/34 and see if that makes a difference