Bike stalls on throttle while hot from stop - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 5 (permalink) Old 08-07-2015, 12:17 PM Thread Starter
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Bike stalls on throttle while hot from stop

Hi everyone,

I have a 2001 that I've done an ear shave to and it works perfectly 99% of the time. I have this one niggling issue.

On a warm/hot day and sitting at a light long enough for the bike to get hot enough for the fan to kick in, if I try to use the throttle to go, the bike will splutter and die. Sounds almost like it's trying to backfire through the carb.

I can get it to restart, but I have to be very careful with too much throttle. Once I get moving again get some air past the bike, it runs fine. If I sit at a light and hold the bike to 2000 RPM and, with the same previous conditions, the bike will move just fine.

I can't determine if this is an adjustment issue or maybe an imbalance between the carbs.

Thanks for any help,
JT
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post #2 of 5 (permalink) Old 08-07-2015, 01:25 PM
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im gonna throw in 2 possiblities...

1. marginal battery/charging performance. the fan puts a big load on the system, and if the voltage drops too low, sheet happens like that.

2. need a pickup coil mod (will help the hot start issues, and may help with the stalling under less than perfect electrical conditions)

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post #3 of 5 (permalink) Old 08-07-2015, 01:34 PM
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1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
TOC MCCTs
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Tuxedo Mod
Rebuilt Forks w/ Progressive Springs
V&H Cruzers
VN750.com Grill Cover
Meanstreak Seat
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1990 Kawasaki Vulcan 750

1998 Honda VFR800 FI

2014 Honda VFR800F

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post #4 of 5 (permalink) Old 08-08-2015, 12:43 AM
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If you get a moment can you please do an introduction in the newbie section?it helps us answer questions if we know your riding experience and wrenching experience. It also helps to give your location cause members close by may be willing to stop by and give a helping hand.thank you and welcome to the forum

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post #5 of 5 (permalink) Old 08-19-2015, 01:47 PM Thread Starter
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Hi everyone, thanks for all of the info. Sorry getting back to reply so late, but I got called away for work.

I found the problem. A month ago, I had a motorcycle shop do a full clean of the carbs and replace some of the internal wear bits. Since I had done the ear shave and have the Vance & Hines exhaust, I have the larger pilot/main jets. Well, when they put it back together, they used the stock size jets. I could visually tell the main jets were too small.

I got new, proper size jets and put them in this morning, and it does sound better. I'm guessing the bike was running lean, causing the engine to run hotter. With the lean condition and hot engine while idling for a while at a light, the engine would stall when I tried to give it a little throttle.

I'll test it out with a full run through traffic, but I'm pretty sure it will run better and cooler and not stall out.

Also, I will try to do those two mods, one for the gap in the timing sensors and the other with the relay for the coil at a later time.

I'm not a newbie, but haven't been around the forums in a while due to work and wrenching on a couple of our classic cars. Now that they are done, I'm getting back working on my bike and transforming it to flat black with some red accents. I'll post my bits in the "hello" section of the forum.

Thanks again,
JT
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