99 vn750 not starting - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
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post #1 of 8 (permalink) Old 09-12-2008, 05:18 PM Thread Starter
 
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99 vn750 not starting

Here's the low down:
'99 Vulcan 750.
Been sitting for two years.
I did get it running and drove it back to my house.
Owner did not drain carbs b4 storage.
VERY hard to start!!! Stays running once it does.
Requires a blast of starter fluid to fire up.
Backfires a lot when trying to start; lit up starter fluid causing me to have to change my diaper. <cheesy grin>
Idles okay runs at nice low temp.
Good low/ bad high rpm power.
Backfires on downshift (like a .22 going off).
After 45mph speed increase comes very slow, I have to ride 3rd and 4th gear to almost 6k rpm to get up to 65 and 5th won't hold at that speed.



I have:
Hot fresh maintainence free battery.
cleaned plugs.
Rinsed tank.
Cut broken ends from hoses and reattached to fuel/vacuum ports.
Cleaned petcock screen.
checked vacuum release of petcock.
Added 3 oz Seafoam (3gal tank).
100 mi on gas/seafoam mix since starting (can't get it over 65mph).
Cleaned out foam air filters.
Changed oil (been sitting 2years).
Crunk in filter screen (no metal thank God!).

In my estimation, it is a bear to remove these carbs from the engine. Is there a "liquid tuneup" that would be suggested?

I think perhaps it is fuel starved so..
Today I will:
Locate fuel filter and check it/clear it.
Reverse build my vacuum valve on my petcock to disable and keep it to full open.
After doing all this I pulled a plug terminal to check spark and... once then nothing
Back on the charger: reassembled with hot battery, now I have spark but... only backfiring
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post #2 of 8 (permalink) Old 09-12-2008, 05:48 PM
 
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Quote:
Originally Posted by Cygnus View Post
Here's the low down:
'99 Vulcan 750.
Been sitting for two years.
I did get it running and drove it back to my house.
Owner did not drain carbs b4 storage.
VERY hard to start!!! Stays running once it does.
Requires a blast of starter fluid to fire up.
Backfires a lot when trying to start; lit up starter fluid causing me to have to change my diaper. <cheesy grin>
Idles okay runs at nice low temp.
Good low/ bad high rpm power.
Backfires on downshift (like a .22 going off).
After 45mph speed increase comes very slow, I have to ride 3rd and 4th gear to almost 6k rpm to get up to 65 and 5th won't hold at that speed.



I have:
Hot fresh maintainence free battery.
cleaned plugs.
Rinsed tank.
Cut broken ends from hoses and reattached to fuel/vacuum ports.
Cleaned petcock screen.
checked vacuum release of petcock.
Added 3 oz Seafoam (3gal tank).
100 mi on gas/seafoam mix since starting (can't get it over 65mph).
Cleaned out foam air filters.
Changed oil (been sitting 2years).
Crunk in filter screen (no metal thank God!).

In my estimation, it is a bear to remove these carbs from the engine. Is there a "liquid tuneup" that would be suggested?

I think perhaps it is fuel starved so..
Today I will:
Locate fuel filter and check it/clear it.
Reverse build my vacuum valve on my petcock to disable and keep it to full open.
After doing all this I pulled a plug terminal to check spark and... once then nothing
Back on the charger: reassembled with hot battery, now I have spark but... only backfiring

It's actually not that hard to remove the carbs, just fiddly and time consuming. How were the carb mounts - does spraying wd40 on them change the idle speed? Apart from ripping them off and giving them a thorough clean it seems like you've done just about everything and if thoroughly cleaning the carbs makes no difference, your on to timing and electrics.

Quick question. Why did the previous owner leave it sit for so long - any idea? Might sound like a silly question but it was a question I should have asked with mine *shrug*
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post #3 of 8 (permalink) Old 09-12-2008, 06:55 PM
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With the lack of power above 45 mph, I suspect you are only running on one cylinder. Could be a clogged high speed jet or it may have come loose in the carb bowl. (This happened to me).
One other thing to check though is the spark. Do both cylinders have it? A quick check is to remove a plug, connect the wire, hold the threaded portion against the engine and have a buddy crank it over. If you see spark, it's a fuel problem. If you don't, it's ignition.

Jim W
93 VN 750 "Ursula"
Moved R/R 08Sep06
R/R rewire 17Feb07
New R/R, Installed 14Jun08
New Stator installed 10 Jun08
Maintenance Free Battery 12Jan08
21480 Miles
VROC #8542
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post #4 of 8 (permalink) Old 09-12-2008, 09:56 PM Thread Starter
 
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It was sitting because some moron told the owner the timing chains were needing replacement: I removed the ACCT's and they have more adjustment in them (almost made the mistake of not winding before putting one on)
Quote:
Originally Posted by compadres_carl View Post
It's actually not that hard to remove the carbs, just fiddly and time consuming. How were the carb mounts - does spraying wd40 on them change the idle speed? Apart from ripping them off and giving them a thorough clean it seems like you've done just about everything and if thoroughly cleaning the carbs makes no difference, your on to timing and electrics.

Quick question. Why did the previous owner leave it sit for so long - any idea? Might sound like a silly question but it was a question I should have asked with mine *shrug*
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post #5 of 8 (permalink) Old 09-13-2008, 03:29 AM
 
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Quote:
Originally Posted by Cygnus View Post
It was sitting because some moron told the owner the timing chains were needing replacement: I removed the ACCT's and they have more adjustment in them (almost made the mistake of not winding before putting one on)

Ahh ok - 'least ya can't blame the owner. I got stiffed with mine it was a runner when I got it, then BAM!! stator croaks, the crap I found since strippin it down sheesh - but in saying that, when it's finally on the road I should have all the bugs eliminated.

Good luck with it, they're a brilliant bike - even with all their faults.
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post #6 of 8 (permalink) Old 09-13-2008, 04:05 AM
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Some folks have had success shooting carb cleaner up thru the carb drain, with the tank shut off. If it were my situation I'd just bite the bullet and pull and open the carb for cleaning. After sitting like that there's going to be alot of "gum" inside, and there are alot of little "nook and cranny's" for gum to collect as well. In the long run it's probably the best way to save time and aggravation.

The gas tank valve is rebuildable too, and is likely gunked as well.
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post #7 of 8 (permalink) Old 09-17-2008, 01:29 AM Thread Starter
 
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Your idea of shooting carb cleaner was a good one, however there was too much crap up in the jets. I wound up pulling the carbs this afternoon. It still runs a little rough but it starts every time now. I'll take 'er to AAA to get 'er registered and just run carb medic and seafoam through the gas tank till she runs smooth... HOWEVER

One of the things I did (because of the backfiring) is pull the ACCT's and I'm worried I screwed up. I managed to get a couple threads on the nut putting it back on and tightened it down about a full turn before making up my mind there's something wrong.. Then discovered I had to pull the cap and wind the ACCT before seating it. I don't know if the sound started before doing this or after, but now I have an intermittent "tink" noise during idle, which goes consistent when I ring the throttle which seems to be coming somewhere from the back jug. Any input?
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post #8 of 8 (permalink) Old 09-17-2008, 01:33 AM Thread Starter
 
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That's Tink every rotation, not every other
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