86 VF500 willnot start

86 VF500 will not start

Gents,

I could use some help in narrowing down the possible issues that are causing my bike to not want to start.
Bike 86 VF500 with about 50,000 kms on it

Overview: Was out on the weekend, and put about 400 KMS on the bike with no issues.
I parked it last night and this morning I went to ride it to work and it would not start.

-The bike turns over but will not fire up with no hint that it might be trying to.
-So we are completely missing either spark or fuel.

What are the common failure points that I should look at first before I go thru the Shop manual's trouble shooting pages line by line.

-Ignition switch failure
-Kill Switch failure
-Bad CDI or related ignition boxes ?
-Clogged fuel filter ?


Thanks

Moose

 

Pull a wire and check for spark at plugs....

Are you out of petrol ?

 

Vacuum diaphragm in the Petcock maybe?

Pending the check that you have spark....
....and pending the next check that Fuel is not getting to the carbs, and that all hose are attached to the Petcock:

Remove the tank and attack a vacuum hose to the nipple (#1) in the picture below


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Suck on the end of the vacuum tube and see if gas flows from the Petcock main outlet (#3 in the pic)
Try this in Primary and RES settings. Gas should flow out when sucking on the Vacuum tube. If not then there may be your problem.

If it is the Diaphragm you can convert it to gravity feed or I have a new diaphragm set from Honda.

 

Full tank of Gas last night

I will check for spark at the plugs tonight whenI Get home from Work - Thanks (forgot about that check) - that wil tell me if the issue is electrical or fuel

Moose

 

Good luck Moose.

 

Thanks - I will check the Vac Diaphram as well.

Moose

 

Nipple sucker ??

Cutting out the diaphram can lead to a crankcase filled with fuel in some cases.

 

To check for fuel flow, drain one float bowl with the screw, then crank engine, and you should see additional drips from open drain screw.

 

Do you see the lights dim when you crank the engine?

 

Yea....maybe.

Being a squirrelman does that make you a nut nibbler? :tongue:

Agreed. If not switched off or if a passerby see's your parked bike and is an A-Hole they can switch it on.

Ah....good idea.

 

Grrrrr - I do not know if she is just being a B**ch but I put the battery on charge for about 30 minutes (because she sounded weak after trying to start her numerous times this morning) .... and she fired right up ... WTF

It did not sound like a low battery issue when I tried to start her this morning ....


"mobtown" - you may have called it

Moose

 

Battery then?

When the battery went on my VF500 I was thousands of Miles away from my house on my trip to the Cape Breton.

The day before I tested it and all seemed fine. Good voltage with the bike on AND off.

Next day I started my trip....stopped every 160-200kms or so for gas....all was great. No issues.

Stopped in Vermont to sleep....next morning the bike wouldn't start. No warning signs the entire day before. None whatsoever.

 

after you charge the battery or even while charging it . check your wires make sure they are seated properly and theat your grounds are grounded... look for burned or melted wires as well.

Good luck

 

Battery was new last year apparently - so it "Should" be fine - maybe itis time for a AGM

It is sitting at 13.6 volts on the bike

I guess I an going to have to keep an eye on this


Thanks everbody for your help so far

Moose

 

Ok Charged the battery Monday night and it started right away

Tuesday morning, yet again It would not start (turned over but would not start)

So I found a battery locally and picked it up at lunch and installed it Last night.

She started just fine this morning, so it looks (Hopefullly) like the old battery would not hold a charge.

I am hoping that it is just a bad battery not an charging or related electrical problem ...


Thanks everybody for all your help !

Moose

 

Odd that a bad battery would still turn the bike over.

It should have made no noise or just clicking.

 

Not really...I've seen the same thing many times. A battery can hold enough charge to engage the starter, but not have enough cranking amps to turn the motor fast enough for a full start.

 

Oh....I see.

 

This is also new to me ... when working on other motors (Granted Injected rather than Carbed), if the starter could spin the motor up without it sounding like it was straining, it would fire (assuming it was getting spark and fuel) ... and this is what was happening on the old battery thus I figured it was a fuel or Ignition problem

So I have added this experience to the "book" of what can go wrong

Moose

 

Ok - Bit of an update

When I had the bike at the V-Four specialist having the Carbs cleaned and sync'ed and the Valve lash done, I also had the mechanic check the electrics and he found that the regulator was on its last legs, so a known good used OE one was swapped in, and all seems to be good

Moose