Bike just started ruuning like crap? - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 14 (permalink) Old 06-15-2009, 08:54 PM Thread Starter
 
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Bike just started ruuning like crap?

I have a 1991 , it has been running good since I got it out this, but last night on the way home it started to sputter and choke at low speed but cleared up somewhat at high speed. It also started to backfire real bad when slowing down. I just put new plugs in it two days ago and cleaned the air filter last week. I also use seafoam about every 4 tanks and have for 2 years. This morning I pulled the plugs and the back ones looked fine but the front one were real wet. I put the wires on the plugs (out of the engine) and fired it to see if there was spark and there was on all four. I am not a bike mechanic by any means. But could anyone help me out on what to do or look for next? I'll be greatfull for any help.
Thanks!
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post #2 of 14 (permalink) Old 06-15-2009, 09:04 PM
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Quote:
Originally Posted by Mark A. Gurnsey View Post
I have a 1991 , it has been running good since I got it out this, but last night on the way home it started to sputter and choke at low speed but cleared up somewhat at high speed. It also started to backfire real bad when slowing down. I just put new plugs in it two days ago and cleaned the air filter last week. I also use seafoam about every 4 tanks and have for 2 years. This morning I pulled the plugs and the back ones looked fine but the front one were real wet. I put the wires on the plugs (out of the engine) and fired it to see if there was spark and there was on all four. I am not a bike mechanic by any means. But could anyone help me out on what to do or look for next? I'll be greatfull for any help.
Thanks!
Sounds like you are getting some debris in the carbs and or the float valve is sticking and flooding out the front cylinder at low speed.


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post #3 of 14 (permalink) Old 06-15-2009, 10:04 PM
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The gasoline of today is notorious for gumming up carbs over winter storage. When the seafoam and such is added it breaks up the gummy stuff and in some cases it clogs the gasoline passages. About the only way to clean it is to dissasemble carbs an give them a good cleaning.

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post #4 of 14 (permalink) Old 06-16-2009, 11:33 AM Thread Starter
 
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got it running a little better, but stil not right!

I messed with it for while this morning. I tapped on the carb (float chamber), drained the bowl and put in differant plugs. I startd it up and ran it, seemed to run better so I took it for a short ride, it seemed to get better but started to get worse. It won't idel, tried adjusting it but can't get it to level out. I did find that there was a hole in the fuel line from the pet cock to the carb. I replaced the fuel line. I pulled the plugs again and the front ones are not wet but they is a lot of blackcarbon on them and the back ones look good. Any one have any ideas?
Thanks.
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post #5 of 14 (permalink) Old 06-16-2009, 11:52 AM
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I'm thinking you got some bad gas, unless you didn't seafoam your full tank of gas before parking for the winter. Either way, I'd add about half a can of seafoam and just go ride the heck out of it for a good stretch. See if it clears up. If not, then I'd pull the tank and drain it and see what comes out. You can drain the tank through a couple coffee filters taped into a funnel. Maybe some junk in the tank. Flush the tank, drain and flush the carbs, put the tank back on and fill with fresh gas, with seafoam and let it fill the carbs and let them soak overnight. Then take her for a ride. If it still runs badly. Give it a good hard run to try to clear it out. If it still has the same problem, I would check my electrical connections to make sure nothing got corrosion on it. Clean your grounds and such. You saw spark, but a weaker than normal spark caused by weak connections can cause the same rich condition. I'd check all this before pulling and cleaning the carbs. Do the easy stuff first! Hope it clears up and you get to riding!

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post #6 of 14 (permalink) Old 06-16-2009, 05:12 PM Thread Starter
 
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Thanks for the help!

I spent the afternoon working on it and rode it for while, it's running better than it did. But it still is not right, I pulled the plugs again and from what I can tell it's got spark but I think the front cylinder has weak spark. Back plugs look perfect but the front hae black carbon on them, which would indicate a eak spark. So since I have no electrical (ohms) meeter I had to bite it and called local shop. The guy is good and very reasonable, it's the parts that will cost the most. Thanks again for the advise, it got me pointed in the right direction. Hopefully I'll have it back good to go by the weekend. Then atleast I'll be able to ride to work. And maybe nex week on my days off I'll take a ride down around the Pa. grand canyon. I live in Addison NY, just north of the Pa. border. I like ride in Pa., no brain bucket!
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post #7 of 14 (permalink) Old 06-16-2009, 05:41 PM
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Quote:
Originally Posted by Mark A. Gurnsey View Post
I spent the afternoon working on it and rode it for while, it's running better than it did. But it still is not right, I pulled the plugs again and from what I can tell it's got spark but I think the front cylinder has weak spark. Back plugs look perfect but the front hae black carbon on them, which would indicate a eak spark. So since I have no electrical (ohms) meeter I had to bite it and called local shop.
Or a Carb loading up the Cyl with excess Gas.

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post #8 of 14 (permalink) Old 06-16-2009, 06:13 PM
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Could be the carbs over filling. I have a tendency to suggest the easy stuff first, rather than going right for the carbs. My reasoning is that the carbs don't create the clogged areas, but are a result of stuff in the fuel system that needs attention. Plus, I throw in the electrical issues because weak spark caused by weak connections can give you the same symptoms, rich burning or not enough spark to burn the fuel at all. It is easier to flush the tank, and to check electrical connections, grounds etc. by far than to pull the carbs, especially on this bike! I hate to see folks automatically jump right to "well, your carbs need a good cleaning!"
Just my opinion, but like I said, carbs don't get dirty by themselves. Yes they may need cleaning. But clean what's dirtying them first. Otherwise, you may put your nice shiny carbs back on and first gas that hits them may have another chunk of crud in it! You wouldn't drink out of a muddy glass would you?
I always throw in my seafoam suggestion as another "easy" thing to do. To some, seafoam might sound like a cop-out, but if you read this forum and search the countless threads where seafoam alone was able to solve issues like this, you would become a believer in it as well. Knock on wood, I had my 750 for a little over three years, and I routinely gave her doses of seafoam about once a month and never needed to pull the carbs. And the one month I didn't ride her, in mid winter, where we had a long stretch of cold and wet days, and I hadn't put seafoam in the tank before I parked it for that stretch of time, the system must have gotten some condensation in it. It ran bad when I finally did start it up, and only ran on one cyl until I got the revs above 2000. I pulled over and got my seafoam out of the saddlebag and added a few oz and started up and rode about a mile, keeping the rpm's pretty high. I pulled into a parking lot and she was idling like new again and has been every since.

I'm certainly not one of the experts on this forum, and don't want to sound like a "know it all", but my point is to try the easy stuff first. When all else fails, or passes, in this case, then at least you know. It's basic troubleshooting.

Fergy
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Rusty Tank Cleaning!
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post #9 of 14 (permalink) Old 06-16-2009, 06:53 PM
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X2 to fergy, do the cheap and easy stuff first.

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post #10 of 14 (permalink) Old 06-16-2009, 09:16 PM
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Make that three. If the SeaFoam works, you're golden and saved a bundle. If not, there's always the shop.

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