Vintage and Classic Hondas

1980 CB750F Popping and Backfiring.

_‹ Previous Topic Next Topic _›

Classic

List

Threaded

4 messages Options

GunnerStaal

1980 CB750F Popping and Backfiring.

Hello Gents,

I recently purchased a used 1980F with about $24k on it. I know that the 'yard I bought it from put a different set of carbs on it due to an issue with hot idling. I still have some issues with it holding at around 3,500 RPMs when it is nice an hot. My concern is around 5k+ range the right exhaust (its a dual exhaust) has a popping/backfiring sound to it. Also there is a light white smoke with a gaseous smell to it coming out of the exhaust.

I am hoping that this is mainly due to the carbs and can be resolved by tuning the carbs a bit.

I am quite green when it comes to all this and the 750F is my first bike so any words of advice are greatly appreciated!

Thank you

GunnerStaal

Re: 1980 CB750F Popping and Backfiring.

Did not preview my message. It has around 24k miles on it. I didn't pay $24k for it.

seestheday

Re: 1980 CB750F Popping and Backfiring.

In reply to this post by GunnerStaal

What carbs are on it? Putting non stock carbs on the bike to cure an idle issue is a weird solution.

1981 CB750K with 900 cams
90K KM's, rebuilt head, rebuilt carbs, upgraded valve stem seals

My wife's recipe website that I'm trying to help promote: Strawberries for supper. Yes, I am a lucky man.

TOOLS1

Re: 1980 CB750F Popping and Backfiring.

Administrator

In reply to this post by GunnerStaal

Sounds like a major vacuum leak. The white smoke is probably oil burning. I hope you did not pay much for it.
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)