My Carburetor Dilemna (1980 CB750K)

[Jonish Rides]

Hi, I am working on my carburetors and trying to figure out the best tune for them. I know basically nothing about how to dial them in. I'm riding a 1980 CB750K I just had the engine rebuilt, its about 800 miles into the break-in and I removed the airbox and replaced with K&N individual air filters. Now my mix is too lean, so I was suggested to the dynojet stage 3 kit. Any ideas? Lay it on me. Thanks!
-Jonish

[LukeM]

The consensus is that the factory carbs for the DOHC 750 work best with the factory airbox. You'll see evidence of this by searching on this forum for airbox and/or pods and see what shows up.

Luke M

[woodsrider250]

+1 on what luke said.  and yes the needle from the stage III kit is apparently the magic part.  Good luck.

[Jonish Rides]

Right im sure thats the best according to Honda, but as I said I put K&N filters on. So Im looking for a good solution to that.

[Jonish Rides]

Any ideas on modifications at higher altitudes? I live in Colorado

[Re-run]

Well woods did kinda give you the answer already. You see the problem is that not every engine runs the same. So it is hard to give an absolute answer. Try the stage 3 and adjust from there. You will probably need an assortment of jets and a lot of time. You may even discover that different carbs will need different jets. That is the problem with tuning for pods.
See the issue with your carbs is they were DESIGNED for the airbox. So it is not that just honda says it is best, it is almost everyone who uses these carbs and most any other constant vacuum carb. The proper operation depends greatly on that vacuum.

If anything, you at least got good pods and not the cheap ones. So that will help a little but once done, you may find that you do not have any extra power over the airbox.

[vern401]

CV carbs are very touchy when it comes to the vacuume they have. They were designed to all share the same vacuume on there intake side which helps in balancing there operation. Since no 2 filters are actualy the same they all give a slightly different vacuume to each carb. this makes tunning them MUCH harder than a shared filter. Here is the Kicker. when you finaly get new pods to replace the old ones you will find you need to re tune the carbs to the new filters all over again.
 dont ask how i know that... I'd rather forget that.