I have a motorcycle and need some insight...

[Michigan Tech]

Hello!

I am a proud owner of a 1981 Yamaha XV750 Virago. Life was good until my bike suddenly died in the middle of the season. No power, lights, dash, starter... nothing. The bike has been put down once, but hasn't been affected from it.

As of right now I've done the following:
-I've fixed the electricals
-new battery
-new starter
-new starter solenoid
-new plugs
-fresh oil
-fresh gas

Now that I have electrics, I tried starter her and all she does is crank over and over and over. There is gas in the chamber (plugs are wet), I've check for spark, good compression.

Why won't it start?? I have a new air filter so I have all the essentials to start it. I've been working on this for weeks upon weeks and I am getting aggravated.

I've got gas. Compression. Air. Spark. I don't need anything else to start her and she still won't start.

Let me know if you have any idea... Let's figure this one out before I lose it (anymore than I already have.. haha)

Thank you so much... And let me remind you, no idea is a bad idea. I want to hear all of it.

Mike

 

[thx1138v2]

Gas, air, compression, spark...everything you need IF the timing is correct.

On the other hand you, might have a stuck float bowl in a carburetor which would give it too much fuel and flood it which may be the case if the plugs are wet with fuel. That happens to my emergency generator if I let it sit up too long.

Take the air cleaner off and squirt a VERY SMALL portion of starter fluid into the carburetor while you are cranking it with the choke open. If it starts and then dies you've probably got a carburetor problem. You might just need to take it apart and clean it if that's not too much trouble. If it is, take the carburetor to a shop that knows how to clean it up. You can buy "rebuild kits" for a lot of carburetors but you might have a problem finding one for this motor.

If you find gunk in the carburetor you probably need to check the gas tank and fuel lines also.

 

[kanewolf]

Timing would be the other obvious thought. If you timing is too far off, then you get spark and compression but not at the same time.

 

[boosted1g]

I have not really worked on bikes before but if you have air, spark, gas and compression then they must be at the wrong time.

Either engine timing is off, or sensors reading timing is bad, or could also be distributor cap/coil issue.

 

[kanewolf]

Could you have the plug wires reversed?

 

[boosted1g]

Could you have the plug wires reversed?

Good suggestion, that would be the easiest way to mess up the firing order.

 

[thx1138v2]

You can find a fairly good shop manual here if you need one.
http://motodataproject.com/download_comfim.php?products_id=35

 

[Michigan Tech]

Could you have the plug wires reversed?

Good suggestion, that would be the easiest way to mess up the firing order.

No, the plug wire are on different sides of the bike. Wouldn't happen, and actually couldn't... I don't even think those wire are long enough... I thought it was timing too, but why on earth would it be a timing problem? It is a chain driven timing mechanism and I have never touched that part of the bike. But I like where the carb thing is going. I will try getting a SMALL portion of starter fluid in there as suggested, and I will let you all know what happens. Thanks for the fast responses guys!

 

[thx1138v2]

Timing chains wear and stretch and sprockets wear. Since this engine is 35 years old and you've never touched the timing chain that could be the problem.

It could also be an ignition timing issue. I'm not familiar with that bike so don't know how to check it with that motor.

I'd try the starter fluid first. If that's the problem you'll need to remove the carburetors to examine the insides of the float bowls and floats. That manual I linked earlier shows how to remove the carbs and also has an exploded view of them.