Final tuning -- Need CBX mechanic in L.A. area

[Write2Paul]

I need professional help ? from a pro CBX mechanic in the Los Angeles area.



Why? I just finished my 79/80 CBX rebuild and?..



-- It starts up on all six cylinders without a moment's hesitation.

-- When the throttle is blipped, the idle speed goes way up, holds for a few seconds, then comes back down.

-- After warm up, the engine seems to run only with choke on. It stumbles at low speeds, then runs smooth and strong at higher rpm.



For the record?

-- I "bench-synchronized" the carbs

-- Plug color is dark, but not wet

-- Valves are all set within spec

-- The timing is spot-on



Is there something else I should be looking for?



If I can afford it, I?d like to have an ace CBX mechanic finish this last part of the project.



Anyone know of an experienced CBX wrench in the L.A. area??



Thanks!



Paul W.

[E Lee]

Paul,

I'd say check for air leak by spray starter fluid around isolators and carbs while running.

Check float heights clear plastic tube connected to overflow nipple hold next to carb at bowl seam, just crack bowl screw until get flow.

Also you may have a stuck slide, look in each carb. While doing this check the slides for smoothness, use finger or wood dowel: and speed of travel. If slow or sticks at all, that's your problem(s).

Later,

Ed

[Dave Ditner]

Sounds like your first problem is caused by improper carb sync. Do it on the bike. From your description of the way it runs, if it's clean from off idle up without the choke and won't idle without it, your idle jets are probably plugged either at the main orifice or the emulsion holes.

[Passx]

Paul, Dave is right, the idle jets are plugged which is why it won't idle and if you haven't done the sync on the bike it will do pretty much what you described, if you get both of these right and it still won't run right several other things to check are the anti-backfire valve, mine was stiff with age (oxymoron if ever there was) or it could be cracked or ripped, also Ed is right about the carb manifold rubbers could be a problem and also stiff from age and not sealing properly.



Also the spring pin for the float needles get soft or stick and you need to replace them and set the float levels, this might help with the black plug color.



Also you didn't say if you had added a jet kit because if you have most jet kits are extremely rich in their initial recommendation which is why they need less choke and get less mpg's. Also have you checked the ignition timing ?

I had all of this on my 80 and had to learn the hard way because I wasn't smart enough to join the club until after I was done with the bike, but I did get a lot of great help & advice from Tim Ware & Bob Franzke, thanks again guy's.



Hope this helps



Steve P. #5220

[Passx]

Paul, Dave is right, the idle jets are plugged which is why it won't idle and if you haven't done the sync on the bike it will do pretty much what you described, if you get both of these right and it still won't run right several other things to check are the anti-backfire valve, mine was stiff with age (oxymoron if ever there was) or it could be cracked or ripped, also Ed is right about the carb manifold rubbers could be a problem and also stiff from age and not sealing properly.



Also the spring pin for the float needles get soft or stick and you need to replace them and set the float levels, this might help with the black plug color.



Also you didn't say if you had added a jet kit because if you have most jet kits are extremely rich in their initial recommendation which is why they need less choke and get less mpg's. Also have you checked the ignition timing ?

I had all of this on my 80 and had to learn the hard way because I wasn't smart enough to join the club until after I was done with the bike, but I did get a lot of great help & advice from Tim Ware & Bob Franzke, thanks again guy's.



Hope this helps



Steve P. #5220