1984 vf500 not starting

The next step then would be to verify that you do not have any vacuum leaks. Check for any uncovered vacuum nipples, unconnected vacuum lines, check/verify the vacuum line that is or used to go to the fuel petcock. Check the carb boots. Check that the vacuum manifold ports on the head are either capped or connected to something.

i.e. each cylinder's intake has a threaded spot near where the carb boots are as a vacuum source. Some of these will be plugged with a screw, some will have a vacuum line like the one going to the fuel petcock. Your engine may or may not still have that line if a previous owner modified your fuel petcock. Maybe I have a photo.

How many times did I say petcock??

 

It would take a lot of vacuum issues to keep an engine with proper spark and decent carbs from at least running, if not poorly.

Assuming there are no gapping holes sucking wind instead of fuel,

and assuming you have good spark, timing, and properly routed plug wires,

either the engine is flooding out or it's not getting fuel.

You've checked flow to the carbs but's it's hard to know what happens from the poin the fuel line connects to the carbs and the spark plug. Not sure if your plugs were wet when you pulled them out?

If it's me, I pour 1 tablespoon or so of fuel down each of the four carb intakes and crank it over to see if it runs for a few seconds. Basically same drill I was going for with the starting fluid. Keep a portable fire extinguisher nearby (legal jargon in case my lawyer is watching). If you pour a tablespoon down there and she cranks, cranks, cranks without firing; try twisting the throttle a 1/4 turn or so.

If it tries to run during this test, you likely have a carb problem and she just isn't getting fuel. You'll have to pull the carb assembly off again and check the fuel screens above the needle/seat valves (and a bunch of other checks while you have the assembly back on the bench).

If it doesn't fire during this test then your bike is straight out of the twilight zone. For it not to run you'd either have to be flooded (but there's no tank on the bike while you try this so it can't continue to flood it out), missing spark but you said there's spark, or lack of compression but you said that's good too. You said there's good fuel flow to the carb assembly so there can't be a problem with the fuel petcock, plugged filters, or shutoff diaphram.

 

No, not really. But the wetness on the plug could be a oil residue and not fuel. You said in post #10 you were going to replace and gap the plugs. Did this happen?

 

I'd like to see real compression test results on this motor with a gauge.

You could have 40psi of compression (cold) and she'd blow your finger off the plug hole while cranking but it wouldn't be enough to maintain combustion and run on it's own.

Have a buddy/neighbor/relative with a gauge? Maybe your local auto parts store rents one.

 

Wouldn't recommend wasting time or money doing an oil change until you've completed the compression test. If the test results are low then you just threw all that oil away.

The engine will run without oil in it at all (although not for too aweful long) so that's not your problem. Low viscocity could be from being watered down with fuel. Changing oil should be high on your list but I wouldn't spend money on filters etc until you figure this problem out. As long as there's something in there and she's somewhat slippery, a little cranking in the garage and a minute or two of idleing isn't going to do any damage.

But that's just me.

 

I got my 500 because someone attempted to replace a cam, and then it would never run again.

Next guy got it and found out the the PO set the cam timing off 90 deg. He fixed the timing and the motor sat on the bench.

I bought the bike as a box of parts. Put it all together, got it running and it clattered like mad. Tore it back apart and found it had another bad cam and the 2nd PO who fixed the timing didn't gap the valves correctly.

Anyway, if your bike has had someone elses fingers in there, it could just be that the valve timing is off. A compression test will help diagnose. Odd thing is, starting fluid will ignite without compression and if the valve timing were off, you should have got a flame ball out the exhaust or the intake if you were doing the test right.

Time (and patience) will tell.

 

What Super-Squirrel said.

I thought you said in your OP that the carbs had been cleaned already?

there is a lot of detail to go thru in a carb cleaning so I'd recommend you consider sending the carb assembly to someone with experiance.

 

Get your money back then.

Bottom line is, the engine isn't getting fuel unless it's choked. Sooooo, your low speed jet, and/or the idle port, are plugged. You can clean the bowls and the sliders all day long and it doesn't matter. You can pull the jets too but it doesn't matter. What gets plugged is the cast passageways in the carb bodies. There are also fuel screens above the needle/seat assembly.