Help please: Recently bought 78 won't start

[Csarnese]

Hey all this is my first post on this forum. BACK STORY- I just recently got my first CB 750 yesterday, its a 1978! When i arrived to the seller he started up the bike, it started right up. It wasn't the prettiest start up iv ever seen (some black smoke) but it was running. Then i asked to see the bike in motion, he drove about 15 feet and the bike cut out. He started it back up and said its been about 10 days since it was on. He rode another 150 feet and it cut out again, and from there he couldn't get it back running. He pulled the choke, kicked it, pressed the stator and nothing. He said it could be the battery. So now this dude doesn't have a running bike at the moment and he was moving in 3 days so he was desperate to sell it. I bought the bike at a great price due this. I put in a new ion battery fully charged, starter makes a very powerful noise like it wants to turn over. I pulled the throttle while trying and nothing happens, it made a loud back fire once. I pulled the tank and made sure the petcock was clear and releasing gas. Turned all 4 carb drain screws and all of them leaked gas. SOOO my question to you guru's is how do i get my new baby running! Whats my next step? Appreciate the help in advance, I was told that CB owners are the most helpful and knowledgeable so I look forward to this!

Cheers, Christian

 

[madmtnmotors]

Start by getting a manual and performing a 3000 mile service/tune up. Manuals can be downloaded here:

http://manuals.sohc4.net/

 

[ethanf]

Usual suspect is a dirty carb and bad gas. I'd honestly drain all the gas and make sure new clean gas is in to begin with. I doubt it was running like a champ previously due to the black smoke and backfire. It should start up fine if it's only been sitting for 10 days.

I second madmtnmotors though--might as well just do a full service tune-up on it to start with.

 

[tommycarl]

You haven't mentioned anything about the spark plugs... easy to check and pretty important. New plugs might help.

 

[madmtnmotors]

A good write up for the initial static timing set up can be found here:

http://www.hondachopper.com/garage/carb_info/timing/timing1.html

 

[Csarnese]

Awesome, gonna print this baby out! thanks

 

[Csarnese]

Thanks for the advice, gonna do the 3000 tune up and cross my fingers!

 

[Csarnese]

Yeah gonna get new spark plugs today

 

[ethanf]

Yeah if the spark plugs are really fouled you might as well replace them since it's usually pretty cheap for the basic copper plugs.

I just recently bought an '82 750C that did run, but seemed like it lacked power and was sluggish. It's amazing what new spark plugs, new oil, clean chain, and a bit of SeaFoam in the gas tank can do.