July 11th, 2013, 03:14 PM | #1 |
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Name: Phil
Location: Aurora, ON, Canada
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Loss of power at certain RPM
Hi all,
Recently, i have noticed that when i hit about 4-5k RPM there is very little power in the bike... feels somewhat like running low on gas. When i get to about 6-7k RPM the power kicks in and gets me going. The bike just rolled over 40,000 KM. Carbs have been cleaned at the beginning of the season, however i know i need to synchronize them. I have a feeling the valves may need reseatting, what do you guys think? Thanks, Phil. |
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July 11th, 2013, 03:34 PM | #2 |
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Are you sure the power loss is related to RPM and not to throttle position?
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July 11th, 2013, 03:43 PM | #3 | |
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Name: Phil
Location: Aurora, ON, Canada
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Quote:
And what would poor throttle point to? I also want to mention that someone pointed out to me that my valves are loud and i did notice that they are clapping louder than usual. I do not know of the history of this bike, owned it since 37,000 km. |
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July 11th, 2013, 04:28 PM | #4 | |
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Quote:
Poor response to throttle position would point to the carburetor. You can eliminate the valves as a starting point if you like, but generally valves out of adjustment would give you low rpm issues such as odd idles and hard to start in the morning situations. I've also thought that the valves get quieter when they are getting out of adjustment, since the ideal adjustment is toward the looser (and louder) end of the spectrum.
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July 11th, 2013, 04:33 PM | #5 | |
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Name: Phil
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Join Date: Jan 2013 Motorcycle(s): 1987 Ninja 250 custom gold Posts: 218
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Quote:
The way i understand it is that valves get louder from carbon build up, and they become "sticky". I have never touched the needle shims in the carb... and it was find before. |
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July 11th, 2013, 04:58 PM | #6 | |
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Quote:
I thought the noise came from the increased distance traveled by the valve stem (hammer) to meet the rocker (anvil).
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July 12th, 2013, 08:12 AM | #7 |
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Name: Justin
Location: Florida
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Surprised nobody has mentioned the main jets being clogged. It's probably the most probable scenario and it is definitely the first thing I would look at. Might as well plan a carb clean.
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July 12th, 2013, 09:33 AM | #8 |
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He said carbs were cleaned recently and that he had plenty of power up top. Do you still think main jets?
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July 12th, 2013, 11:45 AM | #9 |
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July 12th, 2013, 12:07 PM | #10 |
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Name: Daniel "God"
Location: South Florida
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I had this problem and it turned out to be water in the bowls
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July 12th, 2013, 01:30 PM | #11 |
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Name: Phil
Location: Aurora, ON, Canada
Join Date: Jan 2013 Motorcycle(s): 1987 Ninja 250 custom gold Posts: 218
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July 12th, 2013, 02:10 PM | #12 |
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Sounds like dirty carb. 4-5000rpm is around where the carb starts switching circuits(low speed to high speed) If it is a problem that has just started I would suspect a clogged passage in carb. I would try some carb cleaner in the gas first and go out and run it hard for half tank if you can. Hopefully that will clean it out. Check you plugs and air filter too.
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July 12th, 2013, 04:05 PM | #13 |
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I'm betting it's not main jets.
Is there damage to any of the slides or diaphragms inside the carburetors? |
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July 13th, 2013, 10:24 AM | #14 |
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Name: Phil
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July 13th, 2013, 01:40 PM | #15 |
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Have you installed a new fuel filter recently?
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July 13th, 2013, 02:18 PM | #16 |
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Plastic and rubber parts crack and rot over time. It's also possible that the lip of the diaphragm was kinked or something when you it back in the carb. This can cause creases, which wear.
I'm just suggesting things to look for, that's all. |
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July 13th, 2013, 02:58 PM | #17 | |
ninjette.org member
Name: Phil
Location: Aurora, ON, Canada
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Quote:
I have no fuel filter on the bike. |
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July 14th, 2013, 10:28 AM | #18 |
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No fuel filter as in you removed the OEM one???? If thats the case then you're letting anything that can get past the screens in your gas tank in the carbs. It takes the smallest flake to completely clog one jet and take out the cylinder... |
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July 14th, 2013, 11:10 AM | #19 |
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Name: Phil
Location: Aurora, ON, Canada
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Well for one thing, this bike never came with a fuel filter. Furthermore, if it clogs the carb, it can't take out a cylinder...
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July 14th, 2013, 11:12 AM | #20 |
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It takes out the power to that cylinder. Aren't you the one asking for help? Good luck Dill pickle
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July 14th, 2013, 11:37 AM | #21 |
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Name: Lil One
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We're supposed to helping one another not insulting. I can't find any evidence that Dill's bike has a fuel filter.
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July 14th, 2013, 01:32 PM | #22 | |
ninjette.org member
Name: Phil
Location: Aurora, ON, Canada
Join Date: Jan 2013 Motorcycle(s): 1987 Ninja 250 custom gold Posts: 218
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Quote:
@FunnyLettering, i didn't mean to offend you, i tend to over do the periods at the end of a sentence, trying to fix that habit :P |
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