CB750 timing and carb tuning Help!

[romieromes]

Hey Guys,

Just "finished" my cafe build, I need your help to get it running right though.

Its a 1980 CB750 K with 37,000 miles on it. Garage Kept. Didn't run well when I bought it. I put a dyna 2000 ignition and CR29's on it. It starts and idles but bogs out if I give it gas. If I apply the gas really slowly it accelerates a little but sounds like the timing is off.

Basically I need to know how to set the timing and how to tune the carbs.
Also does anybody know of a garage in MD that could do it for me if i can't get it right myself?

Thanks guys!

 

[xb33bsa]

you are right track always ignition first before attempting carb tuning
first you need to make sure the centrifugal advancer moves freely ..,just grabbing the rotor and twisting it AGAINST the direction of engine rotation will give you a good idea... if its notchy or stubborn and dont snap back it needs cleaning and a light lubing
then you really need a strobe type timing light to set the timing at full advance.. with the strobe light you will be able to see the advance happening as you rev above idle.at a certain rpm usually 3500+ it will stop advancing, this is full advance and needs to be on the correct marks,check both sides

 

[Redliner]

Don't be surprised if the mark bounces around slightly. For instance, you may adjust it and see that half of the time it falls right on the F mark, and others it's about 2° advanced. That's fine. Since there are TWO lobes on the points cam that lift each set of points, they won't always be perfectly similar.

When you're doing static timing, that would make you pull your hair out. The solution to static is to rotate, see where it sparks, make adjustment, rotate 360°, ignore the spark at 180°.

If your pipes give a big hollow fart sound as you try to open, it's either lean or not advancing.