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Discussion Starter #1
Hi all, hope you can help me out with this one...

I recently bought a "second-hand" 99 Nomad with V&H bagger dual exhaust and a K&N air filter using the stock air intake housing. When I go to start it up I need to pull the choke and let it warm up for several minutes (5-10 min with choke wide open) before I can get any throttle response with the choke closed. Otherwise, if I jab the throttle, the bike will hesitate, spit and/or stop.

I have also been noticing that when I cut the throttle to decelerate before a slow turn, when I try to accelerate through the turn the bike will often times "buck" and hesitate before jumping back up to the proper RPM (making for a rough ride).

Any ideas? Jetting problem? How can I pinpoint the problem, and then what is the best way of fixing it. I would like to eventually make air-intake mods, but I want the bike performing correctly before I try to screw it up even more... :twisted:
 

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warm-up

Hey there, sounds to me like the carb has partially clogged jets?I would try running Sea Foam through a few tanks of gas and see what happens.It couldn't hurt.
 

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Take a look at your spark plugs before you do anything. Those mods you have might already need re-jetting. Or if the plugs show any lean condition, try opening the idle screw one or a half turn. Also check your idle speed. Sounds like you got short of fuel at lower rpm's

Sea Foam is also worth a try.
 

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a friend of mine has the same problem...we are getting it down to it being a ignition problem....coil or the whole thing...he going to replace everything at one time instead of changing one at a time so we will never know.
 

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Discussion Starter #5
Take a look at your spark plugs before you do anything. Those mods you have might already need re-jetting. Or if the plugs show any lean condition, try opening the idle screw one or a half turn.
What am I looking for on the plugs? Whitish color if the bike is running lean? Do I need to install a fresh set of plugs to get a more accurate reading?

Is there any way to tell if the bike has been re-jetted without pulling the carb? The guy who owned the bike before me kept it in great condition and had all accessories professionally installed, so I'm pretty sure the bike was re-jetted with the aftermarket exhaust..... but I would like to be sure.
 

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Woodies_99nomad said:
What am I looking for on the plugs? Whitish color if the bike is running lean? Do I need to install a fresh set of plugs to get a more accurate reading?
That's my thought. Spark plugs show quite good what's happening inside there. You should be able to use the old plugs (in case they aren't ruined). As bud8fan stated it to be a ignition problem (doesn't ignite every time?), you should be able to see that also. In that case, I'm expecting to see heavy carbon deposit on the spark plug. If they're clean, light tan colored, the problem is somewhere else. At least your fuel/air - mixture is correct.
 

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I have a 98 Vulcan Classic 1500 with the same problem. The previous owner took very good care of it and had the dealer install Cobra Classic pipes and rejet the carb. I give it full choke for 2 minutes, half for two more, then two more minutes without choke.

I've read the plugs and they were o.k. http://www.nightrider.com/biketech/spkplghnbook.htm

It also has the stumble like you said, sometimes when it is hot. I would expect the pipes to turn blue if it was too lean and the plugs and pipes are fine?

Anybody have any ideas?

Thanks,

Grunt
 

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Discussion Starter #8
Well, here's the latest....

I pulled the plugs and I found them to be in very good shape. The ceramics and the electrodes were very clean and the grounding electrodes had a small amount of tan-ish deposits. I did notice that there was a fair amount of carbon buildup on the base of the threads and the base of the grounding electrodes.

In the process of checking my plugs I noticed the left-rear plug wire was not seated the whole way onto the plug. So after checking the plugs I took the bike out for a test ride. It did run better, but it is not 100%. The warm up time still seems excessive and there is still hesitation/bucking during low-throttle maneuvers
 

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re

have any of these bikes had the smog junk removed?
 

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For the intake, I have not "marbleized" my system so the bike still burbs when I shut the throttle at speed trying to burn off the excess fuel.
What is marbleized?

All I can tell is the cat is gone since the bike has Cobra pipes. What else should I look for to remove the smog junk?

Thanks,

Grunt
 

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Discussion Starter #12
What is marbleized?
On the front of the #1 cylinder and on the rear of the #2 cylinder are little black boxes called reed valves. Basically what they do is allow extra air to enter the system when you decelerate to burn any excess fuel thus making for cleaner emissions.

To marbleize your system, you jam a 1/2" marble into the air intakes for your reed valves. This will eliminate the popping you hear on deceleration and will allow your bike to run much cooler.

Go here for more info: http://www.gadgetjq.com/smogstuffremove.htm
 

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This will eliminate the popping you hear on deceleration and will allow your bike to run much cooler.]
I did know that it eliminates the popping but didn't know it would make the bike run cooler.. Does it really do that? How does the engine show it?
 

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Yes, but don't know why the engine itself runs cooler if the excessive fuel is burned in the exhaust system...? Anyway, has the cooler engine any effect on the pinging issue many Vulcans seems to suffer from?? Or do people do this only because of the more silent engine (the solenoids do also keep a lot of noices)?
 

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the air injection is mostly a way to meet epa exhaust specs
flowing pipes make it worse - when removed its out of spec emissions
wise - and the pinging they all get can be all but eliminated with mods and tuning
 
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