Old gas cause bike to not start?

renloy · Posted: July 30, 2009, 7:51 pm Post subject: Old gas cause bike to not start?

So I finally reassembled the bike with new 2-1 exhaust and vm carbs. Poured some gas in and it cranks but won't start. I'm thinking the gas might be a few months old. Could the old gas make the bike not start?

jayel

I think that is not the problem, check for spark, is it getting fuel to the cylinders?

gordo

It is possible, but doubtfull. Poor a little on a fire place , grill, ect. & see if it burn's. If it doe's, which it will, it should be good enough to fire the engine. Try spraying some into the throat of the carb's then crank. Your petcock could not be letting the fuel flow into the carb's.

renloy

I have clear fuel lines so I know the fuel is flowing. Will try new plugs, fresh fuel tomorrow and go from there.

BTW I also installed the green monster coil and new wires/caps if that matters

renloy

So I used a spark tester and I'm not getting any spark on left or right. I installed the coil accoding to instructions on this site so I'm not sure what could be wrong. Is it possible mikesxs sold me a bad coil?

jerseykat1 · Full Member Joined: May 03, 2009 Posts: 79

If you have your old coil handy than just switch it out and see if it works.

renloy

I don't have the old coil. Just tested pickup coil resistance 750 and 760 from each wire to black. Resistance between plug caps 25k. Resistance between the terminals on coil where the two small wires attach (primary?) hovers between 3.2-3.3. Fuses check out good.

Bike is in neutral, kickstand switch disabled

What else should I check?

yamaman

What ignition are you running?

Have you read this thread?

650rider.com/index.php...sc&start=0

renloy

The stock 83 black box

pamcopete

renloy,

Your tests on the coil indicate that the coil is good. Are you getting voltage to the coil? When you test for spark, both plug wires have to be connected to plugs. One of the plugs can be just laying on the engine for grounding and you can see the spark, if there is one.

renloy

I'm using a spark tester that plugs into the plug boot and has a ground wire. Can't see any kind of spark at all when I crank.

I'm an idiot when it comes to electricity so can you explain what I need to do to check for voltage at the coil?

Thanks

pamcopete

renloy,

Try testing with a spark plug grounded to the engine connected to one of the plug wires with the other spark plug installed in the engine, connected to the other spark plug wire. Some of these spark "testers" do not work with a dual output coil.

You will have to have a multimeter to test for voltage at the coil. Set the meter for the 20 volts ot 50 volt scale, shichever is on the meter. Turn on the ignition switch and the kill switch and touch the negative test lead from the meter to ground, with the other positive test lead touching the red/white wire on the coil. Should read the battery voltage (+12V)

gordo

Ren, check for battery voltage at the coil positive side, with just the key on, and while cranking. You should have battery voltage at that terminal during both test's. If not, your gonna have to find the open circut. Check fuse's with a test lite, 'cause a visual test is not good enough! Attach one end of the test lite to the battery negative, then touch the probe end to the positive side, to make sure you have a good connection at the negative side. Turn on the key, then probe each terminal end of the fuse's. Good fuse's will lite the test lite on both end's. A blown or broken fuse will only lite one side. Bad connection's at the fuse's is also a common problem on these old bike's, as well as where the wire's are connected together. The connector's often get corroded over short period's of time.
If I were you, I'd go to the vault & look up Jayel's maintenence/ storage/ purchaseing tip's. He has alot of good tip's already to do the diagnose's on electrical as well as general maintenence.

renloy

I actually tried two different testers. One is just a spark plug that alligator clamps to the engine. I will try with just a grounded plug tomorrow.

y battery is a little low after all the cranking. The voltage on the battery was 11.9. The voltage between red/white wire terminal on the coil and ground was 9.7. What does that mean?

renloy

I checked the fuses with a multimeter too. All good.

gordo

Ren, that mean's you have a dirty/poor connection somewhere between the battery & coil. Check the condition of the kill switch contact's inside the switch itself. Very common area for corrosion. Clean the contact's up real good, then apply some dielectric grease to them, to prevent further corrosion.Re-check the voltage at the coil again, it should be batt. voltage. If not, start in the headlite bucket. Clean those connetor's up and apply the grease to them.That much of a drop is your problem, and you are gonna have to find the bad connection. Trace out the positive wire on the coil back to the fuse's.
You did say '83, right? You got the switch on the kickstand? join the two wire's there together to bypass it for now. You can alway's connect it back up later.If you got about 5-6 feet of 14 guage wire, you can "hotwire" the coil by attaching one end of the wire to the positive side of the coil, then the other end to the positive side on the battery. Check your spark again when you have the jumper in place.

renloy

I just went through my harness and cleaned it up a few days ago. Soldered all the crimped connections, rewrapped it, and greased all connectors. The only connectors I didn't touch are in the headlight bucket because I got lazy and wasn't really sure how to take it apart to get at them (any tips would be appreciated here). I guess that's next on my list.

No kickstand switch. Previous owner took care of it for me.

Will try the jumper. Moving tomorrow and starting new job on monday so might take me a little while.

EDIT: Should I maybe just get a new wire harness? Would that definitely get rid of my problem?

nj1639

The headlight comes out/off by unscrewing 2 screws. Look at the 5 and 7 o'clock position just in from the headlight rim.
Set them aside and then lift the light out from the bottom, first. Then lift up. The light kinda hinges on the top. Undo the connector and set the light aside. Don't leave it hanging from the plug. Seen too many front fenders with a dent in them from doing just that.
Your '83 connectors in the bucket are all 1 of a kind. You can't NOT put them back into their proper / respective connector. Don't be skeered there.
Don't yank the connectors apart by the wires, work the connectors themselves apart. Clean 'em up, di-electric grease 'em and put 'em back together.
Get one of them light probes. They're invaluable when trying to track down a problem in the harness. Under 10 bucks @ your local autowhatever.
Throw that old fuse panel away, do it now. Get inlines. You will get it going.

renloy

Thank you. Should have some updates in a week when I get my bike to the new place. Was hoping to ride it there, but such is life I guess heh

pumps

nj1639 wrote:

.
Your '83 connectors in the bucket are all 1 of a kind. You can't NOT put them back into their proper / respective connector. Don't be skeered there.
.

nj you mean I put those little numbered sticky tags and wrote all that stuff down for nothing?! I'm still askeered! Shocked

nj1639

About the only ones in there that might need labeling are the bullet plugs for the turn signals and a couple of grounds. Tan, green and black with 25+ years of grime on them start to look the same in color.
I had some turn signal and headlight issues with mine when I first got it and the cure was a combo of resolving charging problems (rotor) and corroded electrical connections along with P.O. harness tampering.
Electric start wouldn't work and with the constant nagging from my good Bud and mentor, I finally traced it out using a light probe in the harness, from the battery through just about all the damn safety switches to eventually wind up with a bad starter relay. It takes a bit of time but is cheaper than just throwing parts on and hoping it cures the problem. The satisfaction of finding the cure 'on the cheap' to me is PRICELESS! Ha!

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