Neutral light stays on

My wife's 1980 750K has a hard time starting the first time but starts ok after but i noticed neutral light stays on after it starts even in first gear til you take off and shift into second then goes out but blinks on every time you change a gear. Could it be loose wire or bad switch?

[OTTODOCTOR]

Switch or connections is a good place to start for the neutral light . -- Always check the easy stuff first . -- You mentioned hard starting , but didn't elaborate as to the symptoms . -- These things are cold blooded monsters , especially in cooler weather . -- You might check some of the other posts on hard starting to see if something sounds like your problem . -- Lots of good advice here , and on the dohc customs forum as well . ( www.cb750c.com ) -- Good luck .-- Mark -- aka -- Ottodoctor

Thanks OTTODOCTOR. It has just had carbs completely rebuilt and may just need a little tweaking. Sometimes fires up after a couple of rounds and sometimes runs battery down and has to be put on charger then pops off. I guess i'll live with it.

[brcree]

  Hey Bo...I have a 76 cb750 k.....and had the same prob. Look at your clutch handle and see if there is a wire harness going to it. Mine had a wire broken inside. I soldered it back and it worked. Don't know if your wiring is the same but look and see. Hope it helps.

Thanks, I'm not sure if i have that harness on clutch but will sure check and see.

[brcree]

 Hey, I have found that pullen in the clucth handle, my 76 k fires up with no prob, even when its 30 deg. out side. My batt. would go dead tryen to start mine aswell.

Haven't tried that yet. Battery finally died so i'm waiting til spring to put a new glass mat battery in it then see what happens.

[Re-run]

If you are having that hard a time starting, then something is wrong. Unless it is VERY cold as in ZERO, my 78k starts after a couple seconds of cranking.
In MANY cases, hard starting is caused by the carbs being dirty. You would be surprised how many people think they cleaned the carbs good but totally miss the idle jets.

So here is where you start. Remove the airbox and check to make sure the choke flaps are closing all the way. ALL that way. There is a high idle cam on the carbs that you can adjust IF you want but does not affect starting much, only warm up as in you need to keep a hand on the throttle during initial couple minutes.

A common misconception is that the idle jets are non-removable. They are easy to remove actually AND get very gunked up. Pull your  carbs off and remove the bowls. You see the main of course, it screws in, you will see the idle jet just behind it. Wrap a piece of cloth or rubber around the jet, grab with pliers and twist and yank. Do not wiggle back and worth or you could warp are crack the jet seat. The first jet might seem a pain but once you get it out, the rest will be easier.
There are a lot of holes in these jets that are small. Get a strand of copper wire and clean each hole. Then spray with carb cleaner and then repeat 2 more times. Seat the jets back in and gently rap with a screwdriver handle to fully seat. If you have played a lot with the idle mix, you may want to reset it. Base starting point is 1.5 turns out from lightly seated.
Remember, on the 78 carbs, IN is LEAN and OUT is RICH. Opposite of the 69-76 carbs as these are FUEL screws and not air screws.

Now before putting on the carbs, check the manifold boots. Are they very hard as in virtually inflexible? Do they have cracks? If hard, boil them for a couple minutes to soften them a bit, then mount the carbs. If cracked, new ones are a must.

Once the carbs are mounted, see how it starts. It might be rich or a bit lean but it should start in just a couple seconds with full choke unless it is below freezing then it might be just a bit more.
If starting is still hard, it is time to look at ignition. Do you still have points? If so, check them for deep pits and scorch marks. Also check point gap and set if required. Static timing should also be checked.

Also, what spark plugs do you have? Stock is D8EA, if you have DR8EA, then those are the wrong plugs.
D7EA will work too, maybe a bit better in cold weather but switch back to the D8 plugs once it is 60 out.

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Had carbs rebuilt by certified shop and replaced everything except the throttle bodies. Started great til temps fell below 50 then cranks til battery finally gave up the fight. Put it in 77 degree shop for a couple of hours and will fire with a new battery, but pull it outside for a few hours at 35 degrees and runs battery dead again trying to start. Brother has a 79 and his does the same thing. Was wondering if coils were a problem on the 79 thru 82 models as i've had others tell me theirs do the same thing.

[Re-run]

Problem is that a certified shop would probably not pull out the idle jets. I have know many people to have their bike serviced and run into issues like this and the idle jets are plugged.
The other thing I forgot to mention is the accel pump. Have you verified it is working? With the airbox off, turn on the petcock and twist the throttle. You should see a stream of fuel from the little brass nozzles at each carb opening. If not, then you need to check the pump and make sure it was installed correctly. A lot of places install the spring wrong and the pump is locked open and doesn't pump anything. Or the actuator rod is not adjusted right. There is a tab that pushes against it and should have a .008 gap between it and the rod.

After that, it goes to ignition. I suppose you could check compression as poor compression will affect starting but to have a noticeable impact, your comp would probably need to be below 100.

But I would be willing to bet it is something carb related. I know the shop might be certified but most of these shops have no clue how to work on anything that does not have a computer telling them what is wrong. Just the downfall of an older bike.

The bike had been sitting since 1983 when i bought it. The shop mechanic told me the idle jets were frozen in the seats and had to be drilled then had new ones installed as well as accelerator pump. Replaced air bleeds installed new jets and gaskets. Bike started and ran fine until temps dropped. The service tech at the honda shop told me model years 1979 thru 1982 were known to have a problem with the ignition system as not providing enough spark so suggested a coil change.

[Re-run]

Well I suppose that might be possible. I have not heard of bad coils on those bikes but I have heard of bad CDI units.
If you have to replace coils, you may want to think about getting a new ignition too. There was just a post from polymer about coils that should work that are much cheaper than "motorcycle" coils. You need wires but you would with virtually all new coils.