Hot Starting Issue - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 5 (permalink) Old 06-25-2019, 10:31 AM Thread Starter
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Hot Starting Issue

I noticed a few times on my last trip, trouble hot starting. It's not that it would crank and fail to start, but rather it seemed to not want to crank. It sounds like most Harley's, where they will crank to the compression stroke and go silent for a moment before roaring to life. One time, it just stopped cranking like it couldn't overcome the compression. It fired up just fine on the next attempt.

Battery is good and charging is good. I have no cold start issues. It's only when hot.
But it's behaving like a weak battery.


'89 Vulcan 750 Bought 4/12/18 @ 17805.9 miles $800
Purchased stock. Wrecked once
22490.0+ miles

Completed modifications:
Removed mufflers, straight pipes out of GB
110/90 Front Tire
Pick-up coil re-gapped to .020"
Compufire 55402 r/r series regulator
USB Outlet + Voltmeter
Repainted Metallic Blue w/ new tank bages
Ear Shave (wo/ coasters) 40/140 NO shims 45MPG
MCCT conversion

Planned modifications:
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post #2 of 5 (permalink) Old 06-25-2019, 10:46 AM
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Quote:
Originally Posted by Jason Pittenger View Post
I noticed a few times on my last trip, trouble hot starting. It's not that it would crank and fail to start, but rather it seemed to not want to crank. It sounds like most Harley's, where they will crank to the compression stroke and go silent for a moment before roaring to life. One time, it just stopped cranking like it couldn't overcome the compression. It fired up just fine on the next attempt.

Battery is good and charging is good. I have no cold start issues. It's only when hot.
But it's behaving like a weak battery.
*OR* a dirty/bad/flakey connection. at battery +, solenoid, starter, engine frame to chassis ground, battery neg. thats the current path electricity flows when the starter is cranking (or trying to)

another possibility would be starter needs a rebuild, but thats not as common, but at least its pretty cheap and easy to do

2005 VN750

Sold 11-27-17
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post #3 of 5 (permalink) Old 06-25-2019, 11:12 AM
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Has the battery been load tested? Not just a voltage reading.

When a starter needs rebuilt, it can sometimes crank ok cold, but do exactly as you described when hot.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
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post #4 of 5 (permalink) Old 06-25-2019, 03:11 PM
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just had another thought.. maybe there is a carb leaking a little gas into the cylinder on hot shutdown? that would give similar symptoms

2005 VN750

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post #5 of 5 (permalink) Old 06-25-2019, 04:28 PM
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Hard "hot" starting is common with these bikes. Do you have an AGM-type battery?

Other types, even when "good" seem to have issues starting this thing. AGM batteries fire it right up. More than a few folks have cured their hot starting problems by switching to an AGM battery. It cured mine.

TOC MCCTs
Saddlebags, hard mounted
Fork mounted tool bag (now hard mounted)
Relocated rear turn signals
LED turn signals, brake lights and running lights
LED license plate frame
Engine Guard and Highway pegs
National Cycles Low Boy Heavy Duty windshield
Home made lowers (nice)
Custom seat (made by a local guy)
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Shenko 230 Tour Master tires at 11,123 miles
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