Topic: (cb750K1) Yolanda was dying, then died, now wont start (got it running!)

[brandEn]

In my case the bike was losing spark intermittently and would get worse as RPM's increased because the bike vibrates more. My connector was barely making contact and the bike spit and stuttered, shut off at times and wouldn't start at times. Your connectors might be fine but checking them is much easier and cleaner than fiddling with carbs and fuel. To bad you didn't have a starter, it would make troubleshooting much easier. I may be wrong but since the bike ran with the carbs the way they are now I would guess they are not your problem. I suggest looking at electrical/ignition issues first, that's the way I would approach it if it were my bike.

[cheftuskey121]

You did say that the oil smelled of gas. Dont run the bike for more than 60 or so seconds if it does start.
But with the gas smell that means you got stuck floats.

wouldn't I be experiencing overflow from the bowls? I am not getting any excess fuel drainage with the petcock left on. I put it off of course when I am not standing right by it. its a faint smell of gas. kinda remind me of my dads old 2 stroke motocross bike. or like a lawn mower/weed eater. I am not sure if thats a normal smell for these bikes.

[cheftuskey121]

In my case the bike was losing spark intermittently and would get worse as RPM's increased because the bike vibrates more. My connector was barely making contact and the bike spit and stuttered, shut off at times and wouldn't start at times. Your connectors might be fine but checking them is much easier and cleaner than fiddling with carbs and fuel. To bad you didn't have a starter, it would make troubleshooting much easier. I may be wrong but since the bike ran with the carbs the way they are now I would guess they are not your problem. I suggest looking at electrical/ignition issues first, that's the way I would approach it if it were my bike.

thanks Branden, very logical! will do

[vfourfreak]

Chef,

did you set the air screws back to their original settings ? Two extra turns out is a long way to go. You might have created a new, separate problem.

Kev

[brandEn]

You did say that the oil smelled of gas. Dont run the bike for more than 60 or so seconds if it does start.
But with the gas smell that means you got stuck floats.

wouldn't I be experiencing overflow from the bowls? I am not getting any excess fuel drainage with the petcock left on. I put it off of course when I am not standing right by it. its a faint smell of gas. kinda remind me of my dads old 2 stroke motocross bike. or like a lawn mower/weed eater. I am not sure if thats a normal smell for these bikes.

Yes, if your floats were stuck you would have gas dripping all over the place.  Also, another note. You already verified at one point you didn't have spark and after some tinkering you did have spark. You may have flooded it especially if you were twisting the throttle while trying to start.

[Irukandji]

I have flooded the carb w/o it leaking all over because of the leakage from the petcock.

[cheftuskey121]

That may be true. I don't recall opening the throttle much to get it to start. I use the idle screw to open the slides 3 turns. Once there is fuel in the engine how of I get it out or burn it off etc. lets say this is the sole problem. How do I remedy it. If I am overflowing fuel into the engine but not overflowing the carb bowls how can I check for that and fix it?

So much speculation as I'm at work until 10pm

[Glaede]

Did you try some other plugs after getting spark back? The ones you've got could be dead even though they seem to spark, but under compression it might not spark properly.

[Duanob]

Not over -looking the obvious but how much gas is in your tank? And how clean is your fuel tap? It just sounds like you're out of gas. We've all done it before, go through a whole diagnosis process just to find out there isn't enough gas to keep flowing to the carbs. When you took the tank off to check connections gas could've flowed from one side of the saddle to the other giving the carbs enough gas to start briefly. Until you fill your tank or check the flow out of the tap you can't rule it out. Also all of the kicking can flood your carbs even with too little gas flowing.

Just a thought.

[Vinhead1957]

Check the plugs for fuel.  Begin the detective work. You had overflow before maybe you have gone to the other extreme with not enough fuel.   

[Bankerdanny]

The narrowing of the bell causes the air velocity to increase as it is drawn in from the suction of the intake stroke. The rushing air passes over the emulsion tube drawing fuel from the float bowl and atomizing it into the rushing air, which then flows through the intake passeges and past the valve into the combustion chamber.

[cheftuskey121]

I do not currently have any other spark plugs to test with. Just the rich d8ea and the lean ngk iridium (those are what I used to start the bike today). I have at least a half tank of gas. I have not checked the cleanliness of the petcock, I will do that.  I have a sufficient amount of gas though.

[cheftuskey121]

Vin you could be correct. My number 2 was leaking so I raised the tab on the float. Then flipped the gasket upside down so the float did not stick. I did not reset the float tab to 26mm. So technical I know that float level is low. Forgot to mention that before. Should the plugs be wet at all under normal circumstances? I dont recall them being wet at all.

[Vinhead1957]

No the plugs should not be wet. They should have an odor of burnt gas not a gassy smell. I have had flooded plugs that sparked outside the cylinder but installed they didn't produce enough to fire the cylinder. They come out noticeably wet.

[70CB750]

But the sparks are new, arent they? All 4 bad seems unlikely

I used a whole bottle of seafoam once in motorcycle tank and she would not start on that fuel.

[bjbuchanan]

I would test voltage at the coils. A good battery and good ignition system isn't good for much if corroded/ bad connections produce a large voltage drop by the time you reach the coils. Check power to skillswitch, power after KS to coils and then at coils

Set your airscrews at the 1~ turn and troubleshoot from there

[Vinhead1957]

The truth is in the plug ! Start there inspect smell look at the spark!  Bright and purpleish blue spark for a starting point!  In this case, there is a history of flooding out!

[cheftuskey121]

I will check all connections. There can't be corrosion because
Every single wire and connector has
Been replaced with brand new. I am overkill like that. There may be some looseness but I am positive no corrosion

I have not put seafoam in anything so it can't be that either. I'm more
How do I know of those airscrews are seated. Sometimes thy just keep going in and in. And then I I back of and go in again I can turn it more. Feels like they ever actually bottom out!

[Stev-o]

Screw them in til they touch, don't over tighten, then back out.

You really need to do the full "3000 mile tune up" in correct order or don't expect it to run proper. 
FYI - you don't adjust tappets, it is the valves that need to be adjusted and the timing needs to be set.
A properly tuned warm motor will start easily on 1 kick every time.
I feel like you've skipped steps to get this running.
And didn't someone "warn" you to get it running good before installing the Pamco? [not me]
No offense intended, just trying to help.

[cheftuskey121]

Hey no offense taken. Thats why I am here now. You are correct on all accounts Stev-o. I was basically looking for this kind of affirmation. I will make sure I hit ALL of the 3000 mile tune ups. I think it would be wise for me to go back to stock coils and points. This way I know that i am on track with stock settings. Thoughts?

[Stev-o]

Yes, I agree, go back to stock if you have them are are confident they are good.
Take two steps back...

[Vinhead1957]

Did those screws have springs on them?

[ekpent]

I will check all connections. There can't be corrosion because
Every single wire and connector has
Been replaced with brand new. I am overkill like that. There may be some looseness but I am positive no corrosion

I have not put seafoam in anything so it can't be that either. I'm more
How do I know of those airscrews are seated. Sometimes thy just keep going in and in. And then I I back of and go in again I can turn it more. Feels like they ever actually bottom out!

I know what you mean on the air screws with the springs. Here is what I do when I have a new to me set of carbs that I have cleaned. After the cleaning is done I put 3 and 1 oil or other lightweight on the treads and install. I feel what is bottom then back out and then gently go back in again.More lube will not hurt.After a few cycles usually another 1/2 or more turns can be gained. With the lube and gentle in and out of the air screw you can than find what is the true bottom.

[cheftuskey121]

Did those screws have springs on them?

yes they have springs Vin.

[cheftuskey121]

Yes, I agree, go back to stock if you have them are are confident they are good.
Take two steps back...

here is the strange part. I know the coils and points work because thats how I got it started in december for the first time. funny thing is even with the stock setup it took me 50+ kicks to get it going, and then when I ran it again the next day it took 20 kicks or so. and then the third day I could not get it to run. just like now. just wanted to mention that, because it seems there is a distinct problem regardless of ignition system.