1984 vf500 not starting

will it start on starter fluid?

This will help tell you if the problem is fuel or ignition related.

 

Secondly;

You said it has spark, I'm assuming you've checked for spark on all 4 cylinders?

 

I find it unlikely that valves would be the cause but a compression test should give you an indication if there's a mechanical issue.

If it won't start on starter fluid, I suspect an ignition problem.

If it were me, I'd check ignition on all 4 cylinders and then decide the next step based on the result. Make sure it's good strong spark.

 

oily residue showing up in the coolant isn't the same as creamy white oil from water makeing it into the oil. Oily residue in the coolant can easily just be a 25yr old coolant system that hasn't been properly flushed and cleaned. Even new coolant could show up with residue if it hasn't been properly flushed or if this is the first time it's been drained and replaced in 15yrs.

I wouldn't jump to any conclusions or jump off the deep end just yet. Keep your expenses to a minimum until you get it running on it's own and up to temperature so you really know what's going on. Again, a compression test would help give some clues.

You already said it wouldn't start on starting fluid. That eliminates the fuel system as the suspect. Make sure it isn't flooded out when you are trying to start it with starting fluid by having the petcock off and the fuel line removed from the carbs.

You need to be methodical about this and not jump around from system to system and item to item. If it won't run on starting fluid and it's not flooded out, you have an ignition or compression problem, it's that simple. If it will run on starting fluid, you know you have a fuel problem. Once we identify which path to take, there are plenty more tests to help narrow it down.

One step at a time.

Remember that weak spark can show up when checking the plug against the head. But once you install the plug, under good compression and/or once the plug gets wet, there may be no spark. Usually color will be an indication; yellow and intermittent = weak spark. Sharp blue with a loud snap each time = strong. The front two and the rear two cylinders run on seperate ignition systems, it sounds like you may have known that already.

 

No. Starting fluid/ether in a spray can. In your case, take the tank off and the upper half of the air box. Spray a little bit down the carb air intakes while cranking it over.

Don't spray too much that you create a dangerous condition and be carefull of a backfire out the carbs. i.e., don't have your face directly over the carbs....

This simple test will accomplish a lot. If it won't attempt to run on it's own using starting fluid alone, then we know to start troubleshooting the ignition system (crossed plug wires, pickup coils etc..)

If it does attempt to run on starting fluid then we know to start looking at your fuel system (i.e. petcock, carb float settings, needle/seat valves, vacuum lines etc...)

Make sure you have the run button on the handle bars "on".

Don't sit and spray starting fluid down there all day long as some people feel it's hard on an engine. We just want to know if it will run for a couple of seconds on it's own.

 

You said it sounded like it tried to run on a cylinder or two for a few seconds... Is that with the tank off and spraying starting fluid down the carb bodies while cranking? No backfiring out the exhast or intake?

You say there's spark on all four checking to the head... This is a little confusing based on your comments and not seeing it. If you had good spark, this test would either have had the engine turn over a couple revolutions on it's own using the starting fluid as fuel. If you had good spark but crossed wires would have had starting fluid should go BOOM out the exhaust etc...

If it seemed like it was right on the verge of running, without any backfires etc, while the tank was off and spraying starting fluid then it sounds like a fuel problem. I'm guessing you were maybe just a little cautious about using too much ether.

Please confirm the symptoms.

If that's correct, I'll have you check fuel flow to the carb bodies. With the tank on and the petcock open, have the fuel line that connects to the carb disconnected and pointed into a fuel safe container. Verify that fuel flows freely, no hickups or ultra slow trickles...