[1982 Honda CB750K] Got start problems, included video and picture.

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view

[1982 Honda CB750K] Got start problems, included video and picture.

Hey guys, I've got a Honda CB750K 1982, i bought it last year and it seemed to be running fine.
However at some point it just would'nt start, I thought that since it was an old bike I just had to keep trying, i tried and tried, with and without choke and nothing (well it sounded like the link at the bottom), I recharged my battery tried again. At this point after a two days I thought it might be the spark plugs however, the guy i bought it from said he had just changed them when i bought it (At this point it had been one month).
I decided to check them anyways and they were fouled, im not sure if they were carbon or oil fouled but they were black. So I changed them, i still couldnt get it running after first try, at this point I just thought &#!# it and used some starter fluid to get it running again. I rode it around and put it in the garage pretty happy. The next time tried to start it, it didnt. Same horrible sound.

So now I bought a new battery, still nothing although the "clanking" sound is far more powerful and aggressive. At this point im starting to freak a little, because im really hoping I dont have to check valve clearences and pull the motor out to check carbourators and stuff, I was hoping to do that a little late in the summer. Maybe even fall (September). So now I tried to check the compression but i didnt find the right fit for my tester. But I did find out that the one spark plug I took out is fouled again, it was wet when I took it out, but it dried and is black, here it is note that i wiped my thumb on the top so it was just as dark as the edge.

I also found out that the recommended gap is 0.028 while the ones i was using had a gap of around 0.024. Which is interesting i suppose.. How much of a difference can it make with that gap difference? Im going to get the spark plugs cleaned and gapped correctly, also im gonna check the compression tomorrow. Im hoping for the best.
What else could it be? Listen to  this, it's from 2 days ago, it sounds awful. I'm actually concerned im causing the bike harm by trying to start it now. What could it be ?

Yesterday I cleaned and gapped the spark plugs, and almost got it started by pumping the choke. But it backfired like hell and startled me into releasing the ignition switch. Couldnt get it running again after that as the battery was running low. I did check if all the spark plugs and all of them had a bright blue spark. Im not sure now what that means.
Reply | Threaded
Open this post in threaded view

Re: [1982 Honda CB750K] Got start problems, included video and picture.

There is nothing wrong with the spark plugs. It sounds like your pilot jets are plugged in the carbs. There is a very detailed write up in the "repair tips and tricks" section on rebuilding the CV carbs that are on your bike. Also you can download the Honda factory service manual for free from the manuals section at the top of the home page here. As for damaging the engine by trying to start it, very doubtful, but you could burn up the starter. If an engine does not start running after a few seconds, there is something wrong, and no amount of cranking is going to change that.
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)