Topic: Help diagnosing my problem-cb350f

[Gchatley]

Hello all! Been working through some of the various problems my '73 cb350f has in order to get it (hopefully) running by the end of summer. Here's whats going on: around the first of the year I tore apart the clutch and cleaned the rusty plates, soaked them in oil and rebuilt it. There was no oil in the bike so I didn't roll it around too much but I could tell at that point the clutch was not disengaging. My hope was that when I put oil in (I left for a semester of college) and hopefully got it running I could get a better indicator of what was going on. Here's where the current problem comes in. Put oil in last week, put back in rebuilt carbs and hooked everything up etc. and gave it a kick (missing my starter button) and nothing. It didn't even feel like I was turning the engine over. Pushed it down the driveway and hopped on, dropped it into first and again nothing. Didn't even feel like anything was firing. Pulled off a spark plug and had dad check it as I rolled it around and he said he didn't think the pistons were rolling, which has me scared. Since then I've been crazy busy and haven't touched it but wanted to get opinions before I go after it again. All the electrics work (except i have an extra green wire behind the side cover i couldn't find the connection to) and I can feel the clutch disengage just a little as i roll it around. Thoughts? I might post some pictures when I pull off the clutch case.
Also, where can I buy a carb airscrew? I've searched without fruition, and I'm missing my far left one. I know this is a lot but any thoughts are welcome. Please tell me I'm dumb and this is a simple fix.

[Jimray23]

U should check compression, well first, pull a plug and cover the hole with ur finger and push the kickstarter down to see if it moves any air or if the pistons are even moving

--------------------------------------------------
Jim
1979 kz1000b ltd
    stage 3 cams
    pod air filters
    4-1 open exhaust(no muffler)
    full rewire
    dyna-s ignition
    dyna 3 ohm coils

[Jimray23]

If the pistons are moving then u need to check and adjust all the valves

--------------------------------------------------
Jim
1979 kz1000b ltd
    stage 3 cams
    pod air filters
    4-1 open exhaust(no muffler)
    full rewire
    dyna-s ignition
    dyna 3 ohm coils

[calj737]

Remove all 4 plugs. On the left side of the motor, remove the stator cover and rotate the crank manually with a wrench. Either the crank will or will not rotate. If not, then the engine is seized.

Assuming that is the case, its not the end of the world... But start with that diagnosis before worrying about anything else.

[Gchatley]

I'll run through some more basic checks and check back in when I get a little free time, until then; where can I get carb air screws? I can't seem to find any for the 350f online. Thanks y'all

[scottly]

If the clutch isn't "grabbing" on a 350, the kick-starter won't turn the crankshaft, and neither will pushing it while in gear. You have a clutch problem.

[scottly]

The most common problem with clutch re-assembly is not aligning the splines between the hub and the pressure plate. This is a 750 clutch, but the same principle may apply to a 350?
 

[Bodi]

What carb part do you want? The 16016-333-004 screw set A (metering screw and its spring) seems to be the "air screw" (not sure if it regulates air or fuel on these carbs). These are not hard to find online.

[Gchatley]

So I tested and have compression/ the engine is definitely turning over well which leads me to believe i have a clutch issue. I'm gonna rerebuild and then follow up with results but until then another question, shouldn't i have a spark at this point? Key in, lights came on, pulled the plug out and turned the motor over by hand but it refused to spark against anything. What are some of the common solutions to this? I'm gonna try and attach a picture there was one green cable that i could not for the life of me find a connection to, could that be the issue? Thanks in advance.

[TwoTired]

Simple things first.
Check the bar control stop-run-stop switch.  It directly controls spark power.
Next go to the points and verify 12v across point contacts when they are open and zero Volts when points closed.

[Gchatley]

There should be 12v across across the stop run stop switch correct? I'm not getting anything, but I have voltage to the headlight etc

[calj737]

There should be 12v across across the stop run stop switch correct? I'm not getting anything, but I have voltage to the headlight etc

12v comes out of the Stop/RUN on BLK/WHT wire when key is ON and the switch is set to RUN. That BLK/WHT wire runs to the coils to power them up.

[TwoTired]

There should be 12v across across the stop run stop switch correct? I'm not getting anything, but I have voltage to the headlight etc

Not sure how you are measuring.  The switch bridges power across it, passing 12 v.
Placing voltmeter probes across closed switch terminals won't get you 12v.

12v is measured relative to a reference point.  Where is your reference point?

[Gchatley]

So here's what i just did. Measured voltage across the points and got about 10 closed and 0 open (good) then decided to take off a spark plug boot, and test for power at the boot where the plug would go. Turned over the motor at the points cover and boom it reads voltage spike for a second. This should mean I have spark, so I'll try to kick it when the clutch is back on and see the results. hopefully it fires. I would try to electrically start it but my button for that is missing. thanks all.