Hard cold start in Winter - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 17 (permalink) Old 11-21-2008, 01:52 PM Thread Starter
 
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Hard cold start in Winter

My bike (2001 VN750) is having a hard time staying running without giving it gas for a minute or so on a cold start...

outside temperature is 45 degrees, cold motor, fully choked, twist the throttle a few times. Bike is stored outside.


In the summer time, it starts up fine.

I have not coastered my bike, only capped off the reed valves with giant vaccum caps.

The bike is jetted and the ears have been shaved and I have Vance and Hines pipes.

Carbs have been cleaned and and taken apart many times.

Petcock just taken apart and cleaned.

newer MF battery installed.

Factory Stator and R/R

I have not done the coil mod yet.


Any thoughts or ideas? It almost seems like it is fuel starved or something... Once it gets running and idling properly, it pops alot on decel now since it's really cold outside...
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post #2 of 17 (permalink) Old 11-21-2008, 03:44 PM
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A stupid question but it must be asked. Are you using the choke? The on position is pulled toward you as you sit on the bike. It sounds stupid to ask this but you'd be surprised how many folks don't use the choke correctly.

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post #3 of 17 (permalink) Old 11-21-2008, 04:43 PM
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Yes, and the "choke" is in fact an "enrichment circuit" that is basicly tossing more fuel in. If you need to give it additional gas by twisting the throttle too, then something is not right. At full choke the bikes rpms should slowly rise without touching anything....usualy you need to back off the "choke" as the bike warms up.

How long are you letting the bike warm up?

45 is not that cold, but if you store the bike outside, I would first think you are getting some condensation in the gas tank... but your choke should work for cold starts without having to use the throttle.

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post #4 of 17 (permalink) Old 11-21-2008, 05:57 PM Thread Starter
 
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Yes, it is choked.

I choke it and hit the start button and it will start up for a couple of seconds and dies... I have to help it out a little bit until it can idle on its own. I usually let it warm up to about 3k rpm's then I back the choke off completely (about 1-2 minutes, or enough time to gear up).

If there was any condensation in the tank with an empty tank, I would understand, but not a full take. Water is more dense than gas so it goes to the bottom of the tank which the petcock would not pick up when in the "On" position.
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post #5 of 17 (permalink) Old 11-21-2008, 06:13 PM
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Maybe...

Quote:
Originally Posted by natxbrotha View Post
Water is more dense than gas so it goes to the bottom of the tank which the petcock would not pick up when in the "On" position.
True but, if there were more water than you think or enough to rise to the level (or higher) of the petcock, wouldn't that possibly explain it?

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post #6 of 17 (permalink) Old 11-21-2008, 07:47 PM
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Quote:
Originally Posted by natxbrotha View Post
Yes, it is choked.

I choke it and hit the start button and it will start up for a couple of seconds and dies... I have to help it out a little bit until it can idle on its own.


If that is all the issue is, you needing to "help it out" until the bike warms up and idles on it's own, then your choke, choke cable , or enrichment jet needs adjusting or cleaning.

If the bike runs fine once it is warmed up, it would not be gas. Although "winter gas" is crappier than "summer" gas due to additives.

I'd check to see if the choke is opening all the way, add some seafoam to the tank and not really worry about it if you do know HOW to start the bike when it is cold.

Because you did the earshave and it's always possible your jetting is not perfect. How many miles is on the engine, what brand/weight of oil do you have in it, and the condition of the gas all could make a difference too.

And water does sink in gas but not like a rock...it is as easy as pulling the bike up off the sidestand to make it "spread out" into the gas in the tank and enter the petcock tube.
We did this as an experiment once using blue dyed water and fuel in a small glass tank. The blue water would settle at the bottom, but if you tried to pick up the tank carefully and move it to another spot, the water would swirl up before settling down again.
You can not fill a tank all the way up easily, there will always be air pockets. I'm not sure you have any water in your tank, but if you did, the exact same thing you decribed could occur.

What size pilot jets did you install? Are you using iridium plugs?

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post #7 of 17 (permalink) Old 11-21-2008, 07:53 PM
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That's alot of water! I some times have to "help" the bike start up on cold morning. 40's. And once she warms up she's good to go. Being newish to bikes mostly carb'd engines the whole choke **** is still interesting to me. I've learned alot here about how this bike works. Just an "fyi" is your bike in the cold "tendered"? A strong battery is a world of differencr with this machine. As fall starts I just deal with the little extra "finnegalling". Once the repeated cold starts she's on a tender. Just my 2c worth.
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post #8 of 17 (permalink) Old 11-22-2008, 02:17 PM
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Another stupic question. Do you use the idle black knob on the left side of the bike, this is as you sit on it. Turning it clockwise will put the idle higher than usuall and then as the bike warms up, you have to turn the knob back to get the idle down to normal, after choking and engine warms up. Nothing was mentioned about if you used this knob or not.

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post #9 of 17 (permalink) Old 11-23-2008, 12:19 AM
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Quote:
Originally Posted by weh44att View Post
Another stupic question. Do you use the idle black knob on the left side of the bike, this is as you sit on it. Turning it clockwise will put the idle higher than usuall and then as the bike warms up, you have to turn the knob back to get the idle down to normal, after choking and engine warms up. Nothing was mentioned about if you used this knob or not.
I went back and reread his posts, and it sounds to me like he is just using the throttle and choke. He doesn`t say anything about the idle adjust screw.

Gordon

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post #10 of 17 (permalink) Old 11-24-2008, 12:57 AM
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You said that you've had the carbs apart, but have you synchronized them? Mine acted similar to yours before I synced them. They were never that far off, but it made a world of difference in cold starts, idling, hot starts, and low circuit. I still have not gotten an MF battery, and have had no problems since I synced. If you haven't, there are $1.55 carb sync kits you can assemble from your local Ace Hardware.
http://www.powerchutes.com/manometer.asp

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