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Discussion Starter #1
Hi, I just bought a 1996 Vulcan 750 with 34k miles.

Test drive was fine but it needed to be jumped to get started.

Now the starter will crank but it refuses to start.

Today I replaced the gas with high octane unleaded

Replaced all 4 spark plugs

changed the oil and put in 3QT of 10 w 40

I also replaced the battery

she still will not start...

could anyone help me trouble shoot this problem?
 

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All an engine needs to run, is compression, spark (at the right time), and fuel.
Start with compression to get some indication of the engines internal health.
 

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Discussion Starter #5
All an engine needs to run, is compression, spark (at the right time), and fuel.
Start with compression to get some indication of the engines internal health.
the motor ran great two weeks ago when I test drove it.

But the battery was weak and needed a jump.

could I have blown a fuse?

the starter cranks well with the new battery but it won't fire up.

how do I locate the fuses?
 

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Fuses are located under left side panel, inside the Junction Box. Lift the cover strip from the bottom to release.

Pull all 4 plugs, reconnect plug wires and ground terminals against the engine to test for spark. You want nice fat, bright blue spark.

Compression test specs need to be from 129-199 psi, with 10 psi or less difference between cyclinders.

Get Maintenance Free-AGM battery. Much better than ordinary lead acid wet cell.
http://cgi.ebay.com/ebaymotors/Deka-ETX15L-Powersports-AGM-Battery-100-NEW-/270282472155?cmd=ViewItem&pt=Other_Vehicle_Parts&hash=item3eee173adb

Get NGK Iridium DPR7EIX-9 plugs.

You need almost 4 qts. of oil. Better check the sight glass again. May need to burp air out of new oil filter if the oil pressure light doesn`t go out soon after the engine starts too.

VN750 recommended fuel is regular 87 octane. Higher octane premium is not needed, and can actually make the bike harder to start and run worse. If you live where high levels of ethanol are blended into the gas, that fuel can be problematic too. Try to avoid it if you can. It usually gives less mpg too.

You need to get a service manual. Many of us like the Clymer. There is a free downloadable Kawi vn750 manual available at www.tocmanufacturing.com site, but I am having trouble accessing it today.

Here are some colored wiring diagrams from the vn750 scribed site:
http://www.scribd.com/doc/8941017/circuits

I hope something here is of help to you.
 

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Pull all 4 plugs, reconnect plug wires and ground terminals against the engine to test for spark. You want nice fat, bright blue spark.
.
Never, never do this! You put your ignitor at risk!
9 times out of 10, you get away with it, but that tenth time...OUCH.
Get a spark tester. They go between your spark plug boot and clip to ground.
They are cheap, under $10.00 and well worth it.

Post back.
 

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Discussion Starter #9
Fuses are located under left side panel, inside the Junction Box. Lift the cover strip from the bottom to release.

Pull all 4 plugs, reconnect plug wires and ground terminals against the engine to test for spark. You want nice fat, bright blue spark.

Compression test specs need to be from 129-199 psi, with 10 psi or less difference between cyclinders.

Get Maintenance Free-AGM battery. Much better than ordinary lead acid wet cell.
http://cgi.ebay.com/ebaymotors/Deka-ETX15L-Powersports-AGM-Battery-100-NEW-/270282472155?cmd=ViewItem&pt=Other_Vehicle_Parts&hash=item3eee173adb

Get NGK Iridium DPR7EIX-9 plugs.

You need almost 4 qts. of oil. Better check the sight glass again. May need to burp air out of new oil filter if the oil pressure light doesn`t go out soon after the engine starts too.

VN750 recommended fuel is regular 87 octane. Higher octane premium is not needed, and can actually make the bike harder to start and run worse. If you live where high levels of ethanol are blended into the gas, that fuel can be problematic too. Try to avoid it if you can. It usually gives less mpg too.

You need to get a service manual. Many of us like the Clymer. There is a free downloadable Kawi vn750 manual available at www.tocmanufacturing.com site, but I am having trouble accessing it today.

Here are some colored wiring diagrams from the vn750 scribed site:
http://www.scribd.com/doc/8941017/circuits

I hope something here is of help to you.
Thanks guys!
 

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Discussion Starter #10
First thing to check are the fuses.

Post back.
Hi Sfair, just checked the fuses, all of them look good.

I hooked up one of the old spark plugs and theres no spark when I crank the starter.

Do you think I need a new starter moduel or celenoid?

thanks for all your help.

Please let me know what you think.
 

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Hi Sfair, just checked the fuses, all of them look good.

I hooked up one of the old spark plugs and theres no spark when I crank the starter.

Do you think I need a new starter moduel or celenoid?

thanks for all your help.

Please let me know what you think.
If the starter cranks the solenoid/relay is good.

The battery may be weak though, and not have enough power to fire the plugs while cranking the starter. Check battery for at least 12.5 volts when not running. Charge at no more than 2 amps, if necessary, and try again.
You could try to boost it from a car battery again too.

(Ideal charging rate for any battery is 10% of it`s rated capacity. The vn750`s battery is rated at 14 amp hours, so 1.4 amps is recommended charging rate.)

Most chargers have a 2 amp setting which will be ok usually.

A MC specific battery tender is better for keeping the battery topped up without overcharging it.

If your new battery is not MF-AGM try to exchange it for one.

Please confirm if you are not getting spark with fully charged battery.
We will work from there.
 

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I hooked up one of the old spark plugs and theres no spark when I crank the starter.
Did you use a tester? I have helped many people who swore they had no spark, but when they tried with a tester, it magically re-appeared. It does not make your day to pay big bucks for an ignitor and then your problem not be resolved. Pull only one plug wire off, insert the tester and crank over. Leave all other wires on and plugs in place.
It will be the best $10 you ever spent.
Like I said before, the old laying the plug on the block or sticking a screwdriver in the plug boot is risky to your ignitor. It was OK for a Model A Ford, but anything with solid state ignition, not so much.

Post back.
 

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Discussion Starter #14
If the starter cranks the solenoid/relay is good.

The battery may be weak though, and not have enough power to fire the plugs while cranking the starter. Check battery for at least 12.5 volts when not running. Charge at no more than 2 amps, if necessary, and try again.
You could try to boost it from a car battery again too.

(Ideal charging rate for any battery is 10% of it`s rated capacity. The vn750`s battery is rated at 14 amp hours, so 1.4 amps is recommended charging rate.)

Most chargers have a 2 amp setting which will be ok usually.

A MC specific battery tender is better for keeping the battery topped up without overcharging it.

If your new battery is not MF-AGM try to exchange it for one.

Please confirm if you are not getting spark with fully charged battery.
We will work from there.
Hey thanks man, you were right, I can get a spark but it still refuses to start.

I'm kind of back to square one.
 

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Discussion Starter #17
Ok so here's the update on my project gone weird...

I pulled the air cleaners last night and sprayed some starting fluid into the carbs with the throttle open....the bike started for about 3 seconds.

next thing, pulled and drained the tank.
as an experiment I opened the top of the gas tank and switched the fuel valve to "ON" no gas dripped out.
could I have a clo9g in the fuel valve?
I don't know if this bike has a fuel pump or a gravity feed.

Still playing amature surlock holmes on this one.
 

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You also need air. Check the air cleaners and clean them according to the instructions in the owners manual. also check all hoses
 

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The bike is gravity feed but the fuel valve is automatic, that is fuel will only flow when there is a vacuum on the line. Try starting it without the air cleaners.

BTW you had to jump start the bike originally have you ever ridden the bike any distance 10 miles or more?
 

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Ok so here's the update on my project gone weird...

I pulled the air cleaners last night and sprayed some starting fluid into the carbs with the throttle open....the bike started for about 3 seconds.

next thing, pulled and drained the tank.
as an experiment I opened the top of the gas tank and switched the fuel valve to "ON" no gas dripped out. could I have a clo9g in the fuel valve?
I don't know if this bike has a fuel pump or a gravity feed.

Still playing amature surlock holmes on this one.
What is the news here nickdog? It has been a week since this post.

Have you applied vacuum to the middle nipple on the petcock yet, to see if you have good fuel flow from the two outside nipples?
 
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