Topic: 750F Running Rough When Giving Gas

[YoungBlood]

After my last post, sorting out the starter button switch, I needed to remove the tank to get access to the throttle cables. In disconnecting them, I noticed a boot on carb #3 was torn, so I ripped it off. In doing so, I may or may not have adjusted the throttle top nut that is adjusted when vacuum syncing
When my bike broke down, I had filled up the tank with 87 at Mobil that stated it contained 10% ethanol. Now I am clueless on why the bike is running in stints of acceleration (blubbering) when giving it gas, but might it have something to do with that 10% ethanol gas? Normally I run 92, and made a random switch. However, the bike rode 30 miles home like a top just yesterday.
A few weeks back I did all adjustments twice.
Could it have something to do with the angle of the petcock valve with the fuel lines? I have disconnected this fuel line countless numbers of times, and it looks gunked up from where it pulls over the petcock. I'll send pictures tomorrow. The broken acceleration that bike is experiencing seems like it's not getting gas. Initially I thought that I had run out of gas because that is how it felt.

[scottly]

My guess is that while messing with the starter switch you have messed up the kill/run switch next to it. Check the connections on the kill switch wires, especially the black/white wire that feeds power to the ignition coils.

[YoungBlood]

Thanks Scottly, I’ll take a look at that wire tomorrow.

[Hoosier Honda]

As long as the top lock nut was tight on that carb then turning the adjustment nut wont throw it out of whack. Do you have excess length hose coming of the petcock? If so make sure you didn't hook it back up so that the fuel has to go up a hill like a roller coaster.

[TwoTired]

Was wondering if your plugs are starting to foul.  Pull them and look at tip conditions.

Cheers,

[Alan F.]

It could just be the fuel. Is there much left in the tank?

[YoungBlood]

Scottly, I'm going to take a look at the wire housing in the A box on the front frame. I did disconnect the entire ignition and starter wire set of bullet connectors to mess with the starter button switch. Should I be receiving 12 volts at that bullet connector for the ignition coils when on the "run" position?
Alan, I'm hoping it is simply this darn fuel. I have a fuel treatment additive "104 Octane Boost Lead Substitute, Fuel System Cleaner" that I'll pour a little in.
TwoTired, I'll pull the plugs after verifying what the voltage is on that black/white wire.
Hoosier, I don't think it's the path of travel on the fuel line. The line is short, taught actually, and it never shifts positions. A general descent to the carb ports.

[YoungBlood]

Scottly, you've been on the mark! The bullet connector of the Black/White wire in the A electrical box was not fully seated. It gave it a could push male to female and hear a solid click. Pretty sure that was the problem, about the run the bike. I'll respond.

Also threw some of that additive in there because it can't hurt, screw ethanol! If only I knew a station in Chicago that sold non-ethanol gas, it's everywhere 

[Alan F.]

If only I knew a station in Chicago that sold non-ethanol gas.

https://www.pure-gas.org/index.jsp?stateprov=IL

[YoungBlood]

Thanks Alan, I’ll use this from now on. At the moment bike was running good, I filled up 1.5 gallons with 92. I got into the loop and blew the main fuse . I’m hunting around right now looking for a spare. What might have caused the fuse to blow? Old age, a short, circuit grounding issue? If I have a short can I run a higher fuse to make sure I can get back home (5 miles) where I can safely figure out the short?

[Alan F.]

A fuse with a higher rating could let a wire overheat and melt it's insulation which will cause smoke, this hot wire will continue to melt the insulation of other wires until all of your fuses have blown or your wiring harness is destroyed.

Or your bike has a fire related incident.

I'd use correct fuses only. Check all of the basic functions, lights horn, etc looking for something that doesn't work, then check out the wiring diagram I posted in your other thread, something is shorting somewhere.

I had a horn go bad on a 750 Nighthawk once, causing a fuse to blow. Symptoms were no directionals, horn or tail light (if I remember correctly) new fuse would blow when I hit the horn button. Checking around I found it was all caused by a loose horn mounting stud.

Lesson is that several circuits were run off of that fuse, knowing what they were made troubleshooting easier.

[Alan F.]

Your positive battery terminal connects to the positive terminal on your starter solenoid. Those are 2 connections that you'll want to check first.

Also you may want to clean all of that rust off of the positive terminal on your starter solenoid, and you might want to shine up those fuse holder contacts too.

Edit: what's that other thing connected to the solenoid post with the battery positive lead?

Your photo:

[TwoTired]

Fuses can blow from over current or melt from simply being heated. Over current fuse blows near the center of the strip.  Melted/ overheated fuses separate near the ends.  Heated fuses do so from poor clip connections, and nearby poor solder connections.

Cheers,

[YoungBlood]

Sounds good, I'm going to clean up those connections on the solenoid and my bullet connectors. The fuse "15A Main" kept blowing. I blew about three fuses, finally made it home. I noticed everytime the fuse blew the bike started struggling/hesitating on acceleration. I'm reading about 11.3 from the run switch that powers the coils, and the black/white wire in the connector box. I'm going to hunt around with my volt meter and try to figure out what on the circuit is blowing. All the fuses have blown near the center of the filament.

Is it more than likely my culprit in all of this is the start button switch I copper wired closed? Perhaps it is arcing out of the winding, to the starter switch housing?

Thanks everyone, I'll get back to this tomorrow, bit burnt out running around town for fuses.

[YoungBlood]

Also, TwoTired, I swapped all the spark plugs again when I was at a moto shop that had the fuses I needed. The #4 was very rich, with black (carbon?) deposits on it. It ran the same after swapping them out once the fuse started to blow, and then completely blew. Atleast, that is how I am understanding this, everytime I'd swap a fuse it would run strong, no hesitation, they usually around idle/low rpm, the bike would start stuttering and finally give. Fuse blown.

[Alan F.]

Did you insulate your splice so it wouldn't short to ground?

It seems like everyone eventually gets tired of fussing with the old glass fuses and upgrades to ATC or ATO type like modern vehicles use, since you can find those fuses just about anywhere. There are even regrettable circuit breakers to pop into that style fuse holders.

Glad you got home, it's an adventure some days.

[YoungBlood]

Well I didn't splice the wires that run into the starter button housing. Two wires (I forget the colors) are saudered onto a small rectangular plate. This plate on the other side has two contact points for each sautered wire. There are two arms that extend in the middle of the plate where an additional plate with two contact points rests on top of. The additional plate on top teeters based on the starter button spring and ball bearing moving across it (ie. being pressed), thus changing the plate from one contact point to another.
I only used the two plates, wrapping copper wire around the two plates to force the switch to stay closed. I then put it back in my half destroyed plastic box, and electrically taped up the box into a make shift half plastic/half tap box. Is this possibly what is causing the shorting? The small wire that is wrapped around the switch causing it to stay shut?

Thanks Alan on the circuit upgrade, I'm going to keep that in mind, at the moment I'll clean it up with a brush and some electronic parts cleaner (battery disconnected).

It was fun... until the second fuse blew.

[Alan F.]

Ok I understand a little better how you got that back together. I'm not sure if a fault at that switch can blow the main 15A fuse. But I haven't gotten into the electrical system on my 750k8 yet, it has the same headlight cut-off though.

There is the possibility that a few other dirty connections acting together are raising circuit current above 15A.

[YoungBlood]

I'm going to start with the dirty bullet connections, a lot of them look not so pretty. Is there a good way to get brush access to those connectors? Each female connector on my bike has a plastic over sheath that has been heat sealed onto the wire. Will I have to cut them back to clean them? I'd rather not cut them, or is there some type of replacement coverage I can use other than just plain old electrical tape?

[YoungBlood]

Thanks Alan, I'll refer back to the electrical diagram you posted to figure what is on the 15A circuit.

[Alan F.]

Nope, don't cut those. Instead of a wire brush you can use cheap cotton swabs, I like to use a good, non-flamable contact cleaner like "Lectromotive" https://shop.advanceautoparts.com/p/crc-lectra-motive-electric-parts-cleaner-19-wt.-oz.-05018/7040069-p?product_channel=local&store=6251&adtype=pla&product_channel=local&store_code=6251&gclid=Cj0KCQjwna2FBhDPARIsACAEc_VB3i46WbPHvm1vzzcyATklencHlcOVvTGuiROIRLdBOC6s-mGTV2caAugXEALw_wcB&gclsrc=aw.ds
Use lots of paper towels to catch the crap it washes out, then add some dielectric grease to keep things clean and shiny, helps fight corrosion when things get wet too. Now available in aerosol so you don't spend the whole day squeezing it out the tiny nozzle on the old style toothpaste tube, worth the cost if budget permits, if not use the cheap stuff in a tube: https://shop.advanceautoparts.com/p/permatex-dielectric-tune-up-grease-3-oz.-81153/7730007-P?searchTerm=Dielectric%20grease
If you've used too much, wipe it off and don't worry, just nearly fill up every connector.

[scottly]

Is it more than likely my culprit in all of this is the start button switch I copper wired closed?

YES!!

[YoungBlood]

Scottly, what would you recommend I do to keep that circuit closed for the time being before the 3D printed box arrives?

[YoungBlood]

Looking at the wiring diagram Alan posted on the last thread, I don't believe the starter button could be the cause of the blown 15A fuse. The route leaves the battery straight to the starter relay/solenoid, and then runs into the 15A main fuse. Doesn't that mean it must be the starter relay that is drawing too much amperage causing that fuse to blow?

I am not good with electric diagrams, but doesn't electricity flow in only one direction? I'm going to clean up all the bullet connectors on the starter electrical bundle I disconnected in the A box. I'm also going to clean up the starter relay/solenoid and pop in a new fuse to see if that solves the problem.

As to the copper wired shut box, it makes a lot of sense for that to be the culprit of the blown fuse...but it runs to the 7A fuse which has not blown. Or am I reading this diagram wrong (attached pdf thanks to Alan).

Also since the bike is hesitating on acceleration isn't this pointing to the coils input/output? I read 11.4 volts yesterday at the black/white wire in the off/run/off switch counsel. Battery was at 12.8V. Also new coils, but I was concerned when I installed them that the wires were getting squished under the gas tank...I'll take a look at that last.

[RAFster122s]

If the wired closed starter circuit is contacting the switch body then it is grounding to the handlebars and frame... I am not certain I am interpreting how it is wired closed, so I could be  misinterpreting what was meant.