Ran into some problems :( HELP!!

[Gishman91]

Shinyribs: I dont quite get what your saying. Should I run new petcock and fuel line? Run a filter? all the above lol. New battery or coils? my battery isnt all that old and takes charge.

[motorhead715]

There a ton of possibilities… How long did the bike sit? When was the last time it ran good? Your pilot jets don’t sound like the issue. Does your carb have plastic floats? I had an issue with mine they are not cheap. The carbs would leak out the overflow on the bottom of the float bowl. Are your carbs dripping gas on the ground? It should leak gas out of the carb before it starts to enter the intake port. If gas entered your engine will have a high oil level and oil that smells like gas.

When the problem occurs pull your choke it see if it comes back around if it does its lean, If not you have other issues. Have you done any performance modifications to the bike?

I had an issue with my bike loosing performance around 6500rpm. After a lot of testing I found one coil was dropping spark at higher rpm. I bought two salvage yard coils and they both had high resistance on the primary side. The coil that fixed my problem had about 2.2 ohms on the primary side.

Does the bike idle well?

[Gishman91]

The bike sat all summer. My uncle bought and rode it 3000miles last year. it does have plastic floats.
No performance mods yet because not gunna put alot of cash into a bike i cant get to run. LOL
The bike doesnt run at all. When i try to start it it will jump to 3500 rpms and just die even at full throttle. so it doesnt idle at all.

I just dont know what else to do. 

[Hellbilly429]

Check the timing and also make sure no water got into the ignition cover. If you could even post up a video to show us what exactly it is doing it would make troubleshooting a lot easier

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From: Gishman91 [via Honda CB750'S] <[hidden email]>;
To: Hellbilly429 <[hidden email]>;
Subject: Re: Ran into some problems :( HELP!!
Sent: Thu, Oct 25, 2012 2:53:09 PM

The bike sat all summer. My uncle bought and rode it 3000miles last year. it does have plastic floats.
No performance mods yet because not gunna put alot of cash into a bike i cant get to run. LOL
The bike doesnt run at all. When i try to start it it will jump to 3500 rpms and just die even at full throttle. so it doesnt idle at all.

I just dont know what else to do. 

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[shinyribs]

Gishman91 wrote

Shinyribs: I dont quite get what your saying. Should I run new petcock and fuel line? Run a filter? all the above lol. New battery or coils? my battery isnt all that old and takes charge.

My bad. If the bike is running out of fuel it will not be able to rev properly. Causes could be low float levels,plugged carb passages/jets,plugged or dirty fuel filter/line petcock. But if your battery voltage is low than the bike wont produce adequate ignition to rev properly either.

Sounds like you've check all that out,though. I would probably do what Hellbillly suggested and check the ignition timing next.

[motorhead715]

I believe the fuel valve is vaccuum operated. If you remove the hose from the valve to the vaccuum diaphram and connect that hose directly to the fitting on the carb it may fix your issue. The fitting is located between #1 and #2 carb.  

[seestheday]

You're referring to the autopetcock. Some call it the spawn of satan (SOS). Basically a mess of tubes that sits on top of the carbs.

If the bike has that still installed it may have failed and can cause fuel starving issues.

It is possible to remove it completely and just rely on the float valves or manual petcock to prevent gas leaks.

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From: "motorhead715 [via Honda CB750'S]" <[hidden email]>

Date: Thu, 25 Oct 2012 14:06:24 -0700 (PDT)

To: seestheday<[hidden email]>

Subject: Re: Ran into some problems :( HELP!!

I believe the fuel valve is vaccuum operated. If you remove the hose from the valve to the vaccuum diaphram and connect that hose directly to the fitting on the carb it may fix your issue. The fitting is located between #1 and #2 carb.  

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[Gishman91]

Alright guys heres a quick video of my start up.

http://youtu.be/8U-FsEuvbvk

And just note that this is every time. it'll fire once then be done unless you spray some starting fluid or carb cleaner in it.

[Hellbilly429]

Sounds like it is a fuel problem, like it's being starved. Can you keep it running by revving it up like that or does it just kinda burn off that starting fluid then die?

[Gishman91]

ya it just starts up and dies after burning the start up fuel.

Suggestions?

[motorhead715]

No fuel!... connect a clear fuel hose to the bottom of any float bowl. Lupe the hose up along the side of the carb. Then open the drain screw. The fuel level should be close to the mating surface of the bowl and carb body.  

[motogrady]

My 79 acted like that, it was a cheap/old fuel line kinda pinched
under the tank.  It would get warm, suck into itself, starve motor.

You have good fuel flow where the hose clamps to the carbs?

[robs750]

Here's my 2 cents.....

Bypass the vacuum crap at the petcock like suggested.Once that is done ,verify free fuel flow from tank.
If the fuel does not run out of the tank freely,the petcock could be plugged or there is a vacuum issue such as the fuel cap not venting.

Hook up fuel line to the carbs.Open the float bowl drain screws on the carbs and check to see that fuel runs out of each bowl.
If fuel is not running out then the needle and seat/float needs to be checked.


As far as carb cleaning,I think the wire is suppose to be used in the carb passages as well as the jets.
Did you use compressed air to blow out the carb passages during cleaning??

[Gishman91]

Well guys guess what!!

it is ALIVE!!!!

http://youtu.be/cX6DVLFDTJU 

After reading everyones thoughts did the simplest first. Took the petcock off and cleaned it up and put it back on and it flows fuel now. So awesome!! Im so stoked now. Thanks for all the help.

It has a little miss and needs some fine tuning (idle and such) but rode er' about 20 blocks with no problem.

Again wanna thank everyone for all the ideas and all the thoughts and for being a supportive group of guys. If anyone is near Iowa maybe we could get a meet going.  

Thanks again
Gishman91