Hesitation @ 4-5k - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
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post #1 of 19 (permalink) Old 08-18-2009, 12:48 AM Thread Starter
 
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Hesitation @ 4-5k

Until the bike warms up. Once it warms up, it pretty much goes away. What do you think this could be? I have installed K&N's, ran a few tanks of Seafoam, and just recently installed 4 Iridium plugs. I checked the boot clamps and they were lose, but tightened them, and this didn't help. Maybe I should pull the tank off, and check the primary wire connections to the coils.
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post #2 of 19 (permalink) Old 08-18-2009, 01:29 AM
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Originally Posted by Slip View Post
Until the bike warms up. Once it warms up, it pretty much goes away. What do you think this could be? I have installed K&N's, ran a few tanks of Seafoam, and just recently installed 4 Iridium plugs. I checked the boot clamps and they were lose, but tightened them, and this didn't help. Maybe I should pull the tank off, and check the primary wire connections to the coils.
Most of our bikes do run like crap untill they reach opperating temp. Now there is a difference between pretty much goes away and goes away! Which it it? How old is your bike? How old are the plug wires? What battery do you have? What fuel do you run? Has the bike spent most of it' life inside or outside? How many miles?

The more info the better the diagnosis will be!!

Most likely the cause is a vacuum leak or the carb bowl vent is restricted.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

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post #3 of 19 (permalink) Old 08-18-2009, 03:00 AM Thread Starter
 
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It is a 96 with 20k miles on it. It usually goes completely away. While yesterday, I did noticed it stumbled briefly even after warmed. But no, it usually runs quite well after it warms up. The plug wires look old. Don't know what kind of battery I have. I will look later today. I run 87 octane. There is some surface rust on some of the fasteners, so it might have spent some time outside, but covered.
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post #4 of 19 (permalink) Old 08-18-2009, 04:22 AM
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It is a 96 with 20k miles on it. It usually goes completely away. While yesterday, I did noticed it stumbled briefly even after warmed. But no, it usually runs quite well after it warms up. The plug wires look old. Don't know what kind of battery I have. I will look later today. I run 87 octane. There is some surface rust on some of the fasteners, so it might have spent some time outside, but covered.
Have you checked to see if your carb vent tube has not bottomed out in the back of the right filter cover?

As said before they run better when at temp. You may have a crap Flooded Wet Cell Battery, Get a DEKA ETX15L MF AGM batterty ASAP!!!!!!!!!!!!!

Go to your Auto Parts store and get a tube of Dielectric grease, spend a day or weekend and put a little on every connection the bike has. Just a little dab on the female connector, and YES!!! every connector. You will have to remove the fuel tank, seat, headlight, side covers and neck covers.

AGAIN!!! Replace the battery with the one in the link below.!!!

Clean and or replace the air cleaners. replace left carb to petcock vacuum hose, replace rear carb vacuum hose if it is not capped.

Replace spark plug wires from link below.

WIRES

http://cgi.ebay.com/ebaymotors/Kawas...d=p3911.c0.m14


DEKA BATTERY


http://cgi.ebay.com/ebaymotors/Deka-...4506.m20.l1116

The one you wil get is 210CCA and not 190CCA as listed.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote

Last edited by lance328; 08-18-2009 at 05:16 AM.
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post #5 of 19 (permalink) Old 08-18-2009, 12:03 PM
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My guess is needle/air screw/idle jet adjustments.

DT

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post #6 of 19 (permalink) Old 08-18-2009, 02:39 PM Thread Starter
 
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My guess is needle/air screw/idle jet adjustments.

DT
I think they are 3 turns out.
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post #7 of 19 (permalink) Old 08-18-2009, 02:40 PM Thread Starter
 
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Have you checked to see if your carb vent tube has not bottomed out in the back of the right filter cover?
A
Thanks for the info. What do you mean by this?
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post #8 of 19 (permalink) Old 08-18-2009, 03:05 PM
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If your carbs haven't been modified, there is a vent hose that goes to the right air filter box. From the factory, the hose is cut square and can get up against the filter housing and interfere with proper air flow. When you check it, cut it at a 45 degree angle and put it back. That way, it can't bottom out.

I'm keepin' all the left over parts. I'm gonna use 'em to build another bike!
_____________________________________________
"Black Beauty"
1989 VN750 acquired December, 2008, 6,711 miles
Currently 23,298 miles

Old Blue
2001 Honda CMX250 Rebel acquired July, 2008

1987 VN750 project bike, acquired August, 2009, 33,000 miles and balancer sticking out of the case, currently awaiting attention and parts
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post #9 of 19 (permalink) Old 08-18-2009, 03:11 PM Thread Starter
 
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If your carbs haven't been modified, there is a vent hose that goes to the right air filter box. From the factory, the hose is cut square and can get up against the filter housing and interfere with proper air flow. When you check it, cut it at a 45 degree angle and put it back. That way, it can't bottom out.
Just curious of the area of the housing where the hose goes into. I had the filter cover off to install the K&N, and I didn't see a vent hose.
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post #10 of 19 (permalink) Old 08-18-2009, 03:16 PM
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Then its either slipped out or the carb has been modified. Not sure which is which, but the mod is called either marbleing or coastering. If its slipped out that can cause a lot of problems with the bike running well. One member (Krebsne?) ran his under the tank. It needs to be in a location where the wind can't get to it.

I'm keepin' all the left over parts. I'm gonna use 'em to build another bike!
_____________________________________________
"Black Beauty"
1989 VN750 acquired December, 2008, 6,711 miles
Currently 23,298 miles

Old Blue
2001 Honda CMX250 Rebel acquired July, 2008

1987 VN750 project bike, acquired August, 2009, 33,000 miles and balancer sticking out of the case, currently awaiting attention and parts
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