Topic: '73 CB350F - Ran five weeks ago, dead now.

[Kajo]

First time poster here... hope to start with a bang (eventually):

I have a 1973 CB350F that had been sitting for god knows how long. I eventually got it running by replacing the plugs, charging the battery, and cleaning the carbs. I then let the bike sit for five weeks. I know, I know... gotta run these things all the time. At any rate, the bike is dead now. I will detail below.

-The bike was initially flooded from what I could tell, pulled the plugs... all fuel fouled
-Cleaned the plugs
-I have GOOD spark on cylinder one, didn't test the rest
-I put my hand over the cylinder and cranked the engine, I'm pretty sure some fuel hit my hand so I have fuel. Also... I don't think the plugs would be fuel fouled if I had NO fuel
-I definitely have power... the starter is firing strong, I tried kickin' and pushin' though to make sure
-I tried starting with/without choke
-I've got brake lights, headlights, signals, high beams, etc

Anyone have any ideas?

Edit: I almost forgot... when I turn the key to the run position the neutral light goes on as well as the oil light. Is that normal? When I kick or hit the starter the oil light goes out... it comes back on again when the bike fails to start. I know on my Yamaha warrior the oil light doesn't come on unless you stall the bike.

Edit #2: I have the run switch wires taped together. The damn red thing got loose and the spring must have popped off somewhere in the previous owners shed. At any rate, I couldn't make a solid connection and the bike wouldn't start. I doubt this has anyhting to do with anything because it started before but I figure I should include it.

[dusterdude]

kajo,no ideas off the top of my head,but welcome to the club.

[MetalHead550]

Wecome!  Yep your idiot lights are normal.  Have your checked your plugs since the recently failed starting attempts.  Id say your still flooded.  Make sure theres no gas still sitting in the cylinders, check spark to the other cylinders and go from there.

[Kajo]

Maybe a stupid question... but if there is gas present in the cylinders how am I supposed to get it out? If still flooded should I try to start with choke off?

[TwoTired]

Fouled plugs can be difficult to clean completely.  It doesn't take much of a carbon trail on the center electrode insulator for juice to take that path instead of the gap that provides the visible and igniting spark.  Make certain the spark you see is flowing across the electrode gap and not just at the base of the insulator.

If your plugs are wet, then you are flooding and/or not sparking.

Severe flooding- remove spark plugs and spin the engine a bit to clear the cylinders.
Moderate flooding- open choke (off), throttle wide open, crank the engine.
It may start and die once the fuel has burned off (cold engine).  Then apply choke and start normally.

You'r bike's idiot lights are normal.

A faulty run/stop switch or a faulty connection of those wires will prevent spark from occuring.
Cheers,

[Kajo]

Well I seem to have fixed the problem. Here is my complex solution 

-Buy new sparkplugs
-Take old plugs out and kick the engine over to try and get residual fuel out
-Put in new plugs and start kicking (I tried kicking initially with choke-off, no throttle... then I tried full throttle)
-No affect with new plugs, still didn't want to fire
-At the same time I purchased new plugs I purchased starter-fluid.
-Sprayed said starter fluid directly into the carbs (no airbox and no filters, gotta rectify this I know)
-Kicked bike...  bike fired but died, cold engine
-Applied more starter fluid and choke
-kicked bike and got her running... drove it around for a while

Now I just don't understand what the deal is. I hope I don't have to use starter fluid everytime. Is the spark not good enough off the plugs to ignite the gas in the cylinders or what? And if the spark is not good enough what does that mean? Do I need to replace the coils or something?

On a separate note - Anyone have any idea what the idle should be on this thing, I dialed it into about 1500... seems a little high but I didn't want it to #$%* out on me and it IS a 4 cylinder.

[dusterdude]

i idle mine about 1100 rpm,seems to like it there

[MetalHead550]

How did the bike run once it was runing and warmed up?  If you were able to drive it around then your spark should be fine.  Im guessing your your choke setup is old enough that it only chokes the carbs but doesnt pull the throttle slightly like newer models.  75 550 is like this, so when I start I use full choke and hold the throttle at a 1/8 open then keep the revs at 2K slowly opening the choke as it warms up.  Takes a couple minutes.  Be carefull giving it full throttle like that cuz youll flood it again.  Like dusterdude said 1000-1200 is idea idle speed, at least for the 550.  If it doesnt want to idle at low rpm then you have tuning issues.  Glad you got it running man!

[Kajo]

The bike ran like a champ after it was warm. Well... coming from a 1700cc bike I'm not really sure what a 350 4 cylinder should run like but the throttle response seems good. Ocassionaly the throttle appears to get a little stuck and the bike will only come down to a 2000 idle but if you just twist it forward a little it will settle right down. I chaulk it up to being old and maybe needing a little lube on the throttle cable.

Also...  the bike appears to make the most power above 5,000 RPM... I'll be running in second and if I am below 5,000 it is a real dog, then when 5,000+ comes on the bike picks up almost as if it was turbo'ed. Is this normal or are my idle - low end jets off?

[MetalHead550]

Yeah, sounds like you need to give your throttle cable a shot of lube.  I had the same issue when I first got mine.  Go ahead and give your throttle linkage and choke linkage a good lube too, that will make a difference.  I noticed my bike starting better and more smoothly after freeing up all the moving parts of the choke linkage since their gumminess was causing uneven choking across the carbs(less from 1-4).

Again I speak from experience with the 550, but the powerband on those engines really wakes up after 5 grand and since the 350 is basically a smaller version I assume the powerband is simular.  Sounds normal, and like you said 1700cc to 350cc is a hell of a step down.  I know you said something about not having a filter box or filter on the bike.  Id get that sorted out before diagnosing any air fuel ratio problems since, as you know, running without a filter leans out the mixture.  Once you do you can check your mixture by pulling the plugs and checking them against these...

http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

[GeorgeK]

Make sure you turn off the fuel valve  before you let the bike set. If  any of the needle and seats in the carbs leak it could flood the corrasponding cylindery if the valve is left open. Check the  compression of all 4 cylinders. Low compression could be the cause of hard starts when cold.

George