Max Speed 90mph - Power loss? - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 15 (permalink) Old 03-05-2010, 11:43 PM Thread Starter
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Max Speed 90mph - Power loss?

Hey all. Long time reader, first time poster! lol.

So I gook my 750 out on a little jaunty today, and was unable to get it above 90mph, and thats going downhill, full throttle....... Seems a bit slow to me. It has 12k on it, and is 100% stock with the exceptions of the marble mod and maybe the previous owner altered the exhaust? Tips look cut out to me, but im not sure what they should look like. Any idea on where I should start looking for more juice?
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post #2 of 15 (permalink) Old 03-05-2010, 11:53 PM
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sounds like a one cylinder runner to me... feel the temps of both pipes... don't touch them just hold your hands close enough to feel the heat radiating off of the header pipes, if one feels cooler than the other, chances are you are running on one cylinder. another easy test is to unplug the spark plug wires... when the bike dies then you know which cylinder you have a problem with.

If its not a cylinder missfire, then next thing I would suspect is carbs needing rejetted.
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post #3 of 15 (permalink) Old 03-05-2010, 11:57 PM Thread Starter
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Ok. After running at idle for a few minutes, The rear cylinder pipe is smokin hot, the front cylinder pipe i can hold at 2 inches from motor and not be burnt.......
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post #4 of 15 (permalink) Old 03-06-2010, 12:11 AM
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Bingo you have a dead cylinder, now do you have spark?
Pull a plug and see if it is wet and smells like fuel, If it does check your oil and see if it smells like gas.
I have seen a dead spark cause a motor to fail due to gas in the oil causing lubrication failure.
You can check your spark with a new plug, put it in the wire and rest it on the motor and start, see if there is a spark. good to do this where it is darker so see better.

Chad Falstad "Hawk"
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2011 HD Ultra Classic "angel"
2001 Nomad 1500 Sold March 2012
2001 VN 750 "Sold June with 2008 with 21,000""Serinity"
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post #5 of 15 (permalink) Old 03-06-2010, 12:18 AM Thread Starter
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I pulled both front plugs and they do smell like gas (although didnt appear wet), and when laid against the motor, did spark. Could the be sparking, but very weakly and not doing the job? I have no idea how old these plugs are. I just ordered a set of Iridium's from amazon a few minutes ago.
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post #6 of 15 (permalink) Old 03-06-2010, 01:59 AM
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you might want to replace the wires also. just in case there bad. just a thought.





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post #7 of 15 (permalink) Old 03-06-2010, 02:19 AM
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what color was the spark?
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post #8 of 15 (permalink) Old 03-06-2010, 02:45 AM Thread Starter
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Dull blue
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post #9 of 15 (permalink) Old 03-06-2010, 02:50 AM
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sounds hot to me... next check to make sure that the front carb is for sure getting fuel.
drain the front carb fuel bowl, there is a drain screw on the bottom of the carb...

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post #10 of 15 (permalink) Old 03-06-2010, 03:04 AM
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What color was the plug? You want to see a light brown color.
I'll bet yours was more on the black side.
What number was on the plug? Too cold a plug would cause this kinda stuff also.
Check your aircleaners before you do anything else as they could (and it sounds like to me) dirty.
Some people would say to do a compression check on the front, or both, but with your mileage, I don't think you need to. From what I have read, these motors are pretty much bullet proof.
After you have cleaned the air cleaners and put in the proper heat range plug if it still does this you'll need to clean the carbs.
Good luck getting the pigs off and putting them back on!!!!!
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