Need some help

[adam h]

Hi Everyone,

Pretty much a beginner here but really enjoying my project.  Thanks in advance if anyone wants to point me in the right diagnostic direction.

I have a 1972 750K that I has been sitting for too long while I saved up to have a few expensive things done that I didn't feel comfortable doing myself.  Before taking it to someone, I rebuilt the front brake and cleaned the fuels lines, the fuel tank, and the carburetors.  At this point it was running, although not perfectly as I did not have the tools to synch the carbs.   I then took it to someone to have the front wheel bearing, the steering bearing, and the the swing arm bearings replaced.  When I got it back, the battery was dead so I could not test it right away.

Got a new battery and it wouldn't start.  Replaced the spark plugs and it started.  A few days later I tried and it wouldn't turn over.  What I noticed was that the plugs seem to be drenched in fuel.  Is this from the fact that I am flooding it in my attempt to start the bike or could this be occurring somehow because the carbs are not adjusted properly?  Do you believe these symptoms are connected? Any good suggestions on what I should explore first?  Thanks in advance and let me know if more information would be helpful.  

Cheers,
Adam H
Portland, OR

[TOOLS1]

Since the round top carbs used on the K-2 models did not have accelerator pumps it would be impossible to flood the engine, unless you poured gas down them. Since you say they are covered with gas, I would check the floats. They might be out of adjustment, and letting gas run into the carb. Then check the size of the pilot jets. They might be too large for the engine. Also how is the ignition? Is it firing correctly? A bad ignition will not fire, so the gas stays on the plugs.
TOOLS

[seestheday]

Are you sure it is fuel and not oil?  The mechanic might have done a leakdown test, although I'm not sure why he would have given that he really didn't need to even start it to fix the bearings.

You say it won't turn over, do you mean that the engine literally doesn't even turn when you try to start it, like it has a completely dead battery?

Fuel gets sucked into the engine from the carbs by the engine turning over.  I'm not sure where the fuel is coming from if the engine isn't turning at all.

Fuel evaporates fairly quickly, so if you haven't started it in days, then you should have no fuel sitting in the combustion chamber.  

[seestheday]

Fuel can flow into the engine if the floats stick or aren't adjusted correctly?  Interesting, I learned something new about those SOHC carbs today.  I can't see how that is possible with the DOHC carbs.   Maybe if the overflow tube is blocked?

[adam h]

Hi everyone and thanks for the advice,

I'm thinking you are probably right about a bad ignition.  I'm wondering
what might be the best first place(s) to test?

Not sure if any of these details are helpful:  When I had been trying it
unsuccessfully before (pressing the starter switch) it would often make a
sound as if it was wanting to start (starter would make a whirring/chugging
sound) but would not turn over.  I had figured this was because it hadn't
been started in a while.  The few times I tried the starter switch after
that, it would very quickly "drain the battery" where the lights on the
console would become dim.  I had figured this was because my battery was
worn out.  I now have a solid battery.  When I tried the starter switch
just now, it gave just the faintest single "whir" as if there was not
enough juice to make it turn.  Doing this for a while (it was cold out) and
the single "whir'  got just slightly louder but not even nearly strong
enough of a sound that would indicate it could start the bike.

I'm not sure if any of these symptoms are an indication of what I should
test first - starter switch, coils, battery, points?  If anyone has any
thoughts I'd be most appreciative.
Cheers,
ADAM

[TOOLS1]

That "whrrrr" you are describing sounds like your starter is not engaging. You might need to replace the starter drive clutch, or at least clean it. However that would not have anything to do with the hard starting.
TOOLS

[seestheday]

Yep, what tools said. You might need some new starter clutch springs. These are very inexpensive, and this is a fairly simple job on a dohc.

Sent from my BlackBerry device

From: TOOLS1 [via Honda CB750'S]

Sent: Wednesday, February 5, 2014 11:00 PM

To: seestheday

Subject: Re: Need some help

That "whrrrr" you are describing sounds like your starter is not engaging. You might need to replace the starter drive clutch, or at least clean it. However that would not have anything to do with the hard starting.
TOOLS

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NAML

[adam h]

The idea that it might be my starter is puzzling to me (like many things at this point).

Just to back up for a second to make sure I didn't send us down the wrong track.  

The "whir" I described is the same sound the electric starter button always made before the engine fired.  The difference lately is that the bike never fired up and the sound pretty quickly got dim as if there was not enough battery to power it (though my battery is fine).  Could that be related, as you say, to something mechanical, like the starter, being stuck?  To my laymen mind the symptoms seem more electrical than mechanical.  If it was electrical, where might you test first given the symptoms I described? Bad switch? Sorry to keep playing this one out but any further thoughts would be greatly appreciated.

Thanks in advance,
Adam

[seestheday]

Starters clutches wear out slowly. You probably heard it whir before it caught‎. There are three small springs in there that you need to replace.

Sent from my BlackBerry device

From: adam h [via Honda CB750'S]

Sent: Thursday, February 6, 2014 9:02 PM

To: seestheday

Subject: Re: Need some help

The idea that it might be my starter is puzzling to me (like many things at this point).

Just to back up for a second to make sure I didn't send us down the wrong track.  

The "whir" I described is the same sound the electric starter button always made before the engine fired.  The difference lately is that the bike never fired up and the sound pretty quickly got dim as if there was not enough battery to power it (though my battery is fine).  Could that be related, as you say, to something mechanical, like the starter, being stuck?  To my laymen mind the symptoms seem more electrical than mechanical.  If it was electrical, where might you test first given the symptoms I described? Bad switch? Sorry to keep playing this one out but any further thoughts would be greatly appreciated.

Thanks in advance,
Adam

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NAML

[seestheday]

Also, are you sure your battery is fine? Have you had it load tested? Most car parts shops will do this for free.

Sent from my BlackBerry device

From: adam h [via Honda CB750'S]

Sent: Thursday, February 6, 2014 9:02 PM

To: seestheday

Subject: Re: Need some help

The idea that it might be my starter is puzzling to me (like many things at this point).

Just to back up for a second to make sure I didn't send us down the wrong track.  

The "whir" I described is the same sound the electric starter button always made before the engine fired.  The difference lately is that the bike never fired up and the sound pretty quickly got dim as if there was not enough battery to power it (though my battery is fine).  Could that be related, as you say, to something mechanical, like the starter, being stuck?  To my laymen mind the symptoms seem more electrical than mechanical.  If it was electrical, where might you test first given the symptoms I described? Bad switch? Sorry to keep playing this one out but any further thoughts would be greatly appreciated.

Thanks in advance,
Adam

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NAML

[TOOLS1]

When you hear the "whrrr" is the engine cranking over, or is it just making the "whrrr" sound?
TOOLS

[adam h]

Sounds like you both suspect the starter clutch drive.  In response to your question TOOLS, the "whir" sound is what I would always hear when I pressed the electric starter button.   In the past it would make this sound (more of an electric-type chugging sound) and then the bike would fire up. I don't think that sound was abnormal.   Now I just hear the sound and it won't turn over, and in the past few attempts, that sound grows dim as if there is not enough battery power to start the bike.  It's the electrical symptoms I'm hearing that puzzle me? I will have the battery tested once again to rule it out but it is a new battery.  ANy other thoughts?  Thanks again.
Cheers,
Adam

[TOOLS1]

Let me see if I understand what you are trying to describe. The "whrr" sound is the starter motor cranking the engine over, and by "turning over" you mean "starting". If this is the case, they yes the "whrr" should slow down as you drain the battery. As for not starting, you need 3 things for an engine to start.
 1. Spark. Pull a plug, hook it back to the wire, and ground the threaded part to the head, and crank the engine, and watch for spark.
 2. fuel. Are you getting gas to the carbs? Is the gas going through the carbs to the combustion chamber?
 3. compression. Run a compression test if #1, and #2 test OK.
TOOLS