CB350 runs rich (among other things)

M

mikeat

New Member
meet my 1972 honda cb350 project:

bike.jpg

BIKE2.jpg


here's the battery box/battery/Rick's Regulator/Rectifier unit (which may be important, but we don't think so):
batterybox.jpg


here's what the bike is doing to sparkplugs:
fouled.jpg


full story:

I bought the bike, which ran pretty much perfectly, and immediately started tearing it down (which is probably where I messed up). Painted the motor and exhaust, among other things. Had the frame powdercoated. Replaced the stock airbox/battery box with the stuff pictured above. I am running Emgo shorty mufflers, and Emgo pod filters (I know about the reported problems). The carbs were cleaned and rebuilt, but at this point are back to stock jets. They are the Keihin 722a model.

The bike won't idle without choke. It seems like maybe the right side of the motor is missing.

No matter what we do, the bike runs rich. Pod filters on, pod filters off, no matter where the air/fuel screw is (even completely out), the bike runs rich and uneven.

We've checked voltage out of the battery, and it seems to be right. We've checked for vacuum leaks, and found none. Fuel lines are fine. Took the carbs off and apart, float level is right and checked twice, everything is clean.

We did notice that the bike didn't seem to be grounded well (thanks to the thick frame powdercoat) - we noticed a spark jumping across one of the motor mounts. We thought this was our problem, but regrounded the motor, and still have the problem.

At this point we're out of ideas, which is why I'm asking for help. Any suggestion will probably be attempted, because we're really scratching our heads here.
 
Any help or ideas would be greatly appreciated!


Our only solution at this point is to stand around and drink more beer.
 
I can almost guarantee you that the timing is off somewhere. The Honda twins are stupid sensitive to ignition timing, and just a little retarded will foul plugs easily. That's where i would start. A good strobe is a great investment.
 
Kanticoy said:
I can almost guarantee you that the timing is off somewhere. The Honda twins are stupid sensitive to ignition timing, and just a little retarded will foul plugs easily. That's where i would start. A good strobe is a great investment.
Click to expand...


I have a HF strobe. Is it fine to have the left cover off and run it?
 
Yeah, just be prepared to clean up a little oil afterwards ;)
 
Have you set the points gaps and timing correctly per the manual? What are the carbs? CV type from a 350?
Are they opening at the same time, synched?
 
We've already checked and reset timing, but as Andrew Mothgils noted above, we'll recheck. Points gaps are right per the manual. Carbs are Keihin 722a, synced, at least by eye.
 
Another thing to note is that the only mods made to the motor were paint, and the bike ran fine before we took it apart, so timing issues would be pretty odd. But we checked and will recheck anyway.
 
Not trying to insult here, but a lot of CB350 owners make this mistake. You mentioned that it won't idle without the choke, are you sure you are using the choke correctly? The choke lever on the Keihins is confusing to a lot of people. You push the lever down (turn clockwise) to open the choke and the opposite to close. They are known to close while riding too from the vibration.

Probably not it but worth a try.
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light
    • www.jadusmotorcycleparts.com
    www.lostapostle.ca/
    www.sparckmoto.com

    Spread the Love

    Back
    Top Bottom