Hello,
I am new to the forum, but I am about light my bike on fire and walk away. So, I thought I should try to find a solution from y'all before I grab the matches.
My 85 700 Magna just had the carbs rebuilt and the guy cracked the body of it so I bought a refurbished one on eBay and installed it. Also just put on new plugs, fuel filter, flushed all the fluids and replaced the brake and fuel lines that had dry rotted.
So now the problem: It starts, runs and idles fine as long as the petcock is off, but as soon as I turn the petcock on the bike sputters and dies. Any idea what might be the issue?
Here is a YouTube video of my bike and the problem.
hxxps://youtu.be/741FfwOb5xI
Or search YouTube for 1985 Vf700c Magna fuel issue
Sounds like the lever is out of wack with the valve position. Isn't there a little screw in the middle that will allow you to reposition the switch. Now on the 3Gs the US petcock lever position is backwards to the way I think it should be. On is perpendicular to the flow. The Canadian version got it right with the lever in line with the flow. maybe there are 2 versions on your model also. If thats the only problem I had with my bike I would get over it really fast, wouldn't sweat the small stuff, take some vyvanse and enjoy my bike.
The fact that I paid someone to fix my carbs who ended up damaging them that he didn't cover and I had to pay for would tick me off a lot more than a backwards petcock lever but thats me.
That's a good idea. Check to make sure the petcock lever is actually aligned correctly so that you are indeed opening it.
Assuming the petcock is in the correct position
The other thing I noticed is that it sounded like the RPMs increased for just a bit right when you initially opened the petcock. To me that would indicate an increase in fuel flow. So I'm wondering if the bike is dying because it's actually flooding out instead of starving from fuel?
On a 3rd generation Magna when you close the petcock it can idle for quite some time before the engine will flutter out. Yours is not a 3rd gen but I think it should be similar. All my bikes with pet cocks behave that way. That's why I think you're actually flooding it out, because the RPMs raise and then it dies so quickly.
So why is it flooding? My guess would be you have a sticky float (or floats) and the bike runs OK when it doesn't have fuel pressure, but when you open the petcock it just opens the flood gates.
Anyway... That is just a theory. I'd wait to hear what other people say too.
Quote from: MagnaMan on June 15, 2016, 01:01:36 AM
So I'm wondering if the bike is dying because it's actually flooding out instead of starving from fuel?
Wouldn't that be easy to check for. Turn the petcock on, wait for it to die, crank a few more times than pull the plugs to see if they are wet?
Sounds like a plan.
The petcock is fine, if opposite of normal. The bike is definitely flooding I already knew that. I have already pulled the carb and checked for sticking floats, but they aren't.
There is also float adjustment as far as when fuel is allowed to flow into the bowl and when it's not when full.