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Discussion Starter #1
Hello,

I've got a question about which pickup coil goes to which cylinder. The coils are at 10 o'clock and 8 o'clock. When the timing mark for the front cylinder is lined up with the pointer. The raised tab on the rotor is at the coil at 8 o'clock. Is that the front pickup coil? If it is then the 10 o'clock coil is for the rear cylinder?

What is the factory air gap at the coil and tab? I have looked at the p/u mod
and understand what it is saying and think we will probably end up doing it.

Here is the problem we have. The rear cylinder has nice fat blue spark. The front has no spark at either plug.

I did the tests that Clymer recommends on the p/u coils. Both within spec.
Did test on primary and secondary on both ignition coil. Both within spec.
Did test on sparkplug caps. All 4 within spec.
All 4 plugs brand new Champions
Brand new Yausa wet cell battery
Tank drained of old gas, carb bowls drained of old gas. New gas with Seafoam.

I didn't test the tci because Clymer says it takes special kawai tool to test. Is that true?

I think the source of the problem is that when the balancer let go, the stuff grinding away inside scuffed the trigger tab. Causing the air gap to be to wide.

Does that make sense?
 

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Discussion Starter #4
Today I regapped the plugs .035. The air gap at the rotor was .032 on both p/u. With the long tube plugs in I had good compression(the old thumb over the hole test) popped my thumb off hole.

Checked for spark on plugs not installed. Both front and rear plugs have spark.

With all plugs in the starter doesn't have enough uumph to turn the motor over fast enough. The battery is new(wet cell bought for xs650 project) I have jumped it with a jump box, a 200amp start/boost battery charger and I even jumped it with a car (not running).

Would a AMG make a big difference?

Do these bikes turn over slow as a general rule?

The cable to the starter looks as though it's been overheated more than once. The coating is bubbled and melted. Could that cause more resistance?

Is there a starter mod that increases starting power ie. better grounding or a 4 brush starter? Does kawai have a 4 brush starter?
 

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Calif Rider
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How old is the bike, or how many miles on it? Sounds like the stater motor is bad,or dragging. You can get a rebuilding kit for the starter on Ebay. You can take the starter off and get it tested at a auto parts place. It seems your getting enought voltage to the starter because your melting the positive cable by trying to start it.
 

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Linkmeister Supreme
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Try hooking the positive jumper cable directly to the terminal on the bottom of the starter case. If the starter spins quicker or starts the engine that way, you can eliminate it as the problem.

You can also take the mc battery out of the circuit and just boost directly from the car battery to the mc battery cables. Boosting a worn out or too small battery doesn`t work as well as just taking it out. If your battery for the XS650 is not rated at least 14 amp hours, it may not be big enough, even though it is new.


I don`t know of any other starters that will fit the 750.
However there are rebuild kits available on ebay.

Thumb over the spark plug hole is not a very reliable compression test. 100 psi will blow your thumb off the hole, but is not enough for a well running engine. vn750 specs call for 129-199 psi compression, and a difference no greater than 10 psi between cylinders.

Yes a Maintenance Free- Absorbed Glass Mat (AGM) battery usually makes a large difference.
This is a good one at a reasonable price.
http://cgi.ebay.com/ebaymotors/Deka...em&pt=Other_Vehicle_Parts&hash=item3eee173adb
 

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I had a slow cranking on my bike... it was a short in the wiring. Eventually, after weeks, maybe a month or two, I got smoke coming out from under the seat. A cable's insulation had melted.

I had no idea what the slow cranking was until I saw that cable. I found the short, took care of it and immediately the bike cranked fast again.

If you already see a cable that is melted, it's likely that you have the same issue!
 

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Today I regapped the plugs .035. The air gap at the rotor was .032 on both p/u. With the long tube plugs in I had good compression(the old thumb over the hole test) popped my thumb off hole.

Checked for spark on plugs not installed. Both front and rear plugs have spark.

With all plugs in the starter doesn't have enough uumph to turn the motor over fast enough. The battery is new(wet cell bought for xs650 project) I have jumped it with a jump box, a 200amp start/boost battery charger and I even jumped it with a car (not running).

Would a AMG make a big difference?

Do these bikes turn over slow as a general rule?

The cable to the starter looks as though it's been overheated more than once. The coating is bubbled and melted. Could that cause more resistance?

Is there a starter mod that increases starting power ie. better grounding or a 4 brush starter? Does kawai have a 4 brush starter?
Are you the original owner of this bike? Maybe this bike has a history of hard starting that was at times very frustrating to the PO. I would suggest (since you are in there already) the ignition pickup coil regap to .020", x2 on the iridiums. Remember, whatever energy passed through the scorched wire, may also have passed through the device on the end of it. I would check to make sure the starter motor brushes were still in good shape. They may be somewhat pitted reducing available energy for torque.

good hunting.
 

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Discussion Starter #10
Hi,

This is going to morph into a starter thread. Yesterday I took the starter apart. Before I did I turned it over by hand, it turned over kind of choppy. I assume this is because of the magnets right?

The commutator was a dull copper color not shiny. I cleaned it with some emery cloth. Has there ever been a grounding issue between the brush plate and the frame?

On yamaha's first gen ventures the ground between the brush plate was a small tab that didn't work that great. Some owners modified thier staters with a ground strap between the brush plate and end cap of the starter.

We're going to try a heavier start cable #4awg and an additional ground strap from the starter mount bolt to the frame.

Do any other vulcan starters fit ie. vn1500?
 

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did you test your starter by applying 12V to it before taking it apart?
 
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