CBR 1000F "Hurricane" 1987-1996 CBR 1000F

Rough Ride at 8000

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Old 01-05-2013, 11:38 PM
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Default Rough Ride at 8000

Ok so for those of you who saw my last post you already know, but i recently put a new kevlar racing clutch on my 1000f, and even with the old clutch, at 8000-9000 rpms, and only in first gear, the bike jerks a little, and then continues on towards 10k, and its not as if the engine in losing power, because it is solid all the way through. Origionally i though it was the old clutch, which did slip a lot but now i cant seem to figure this one out. It only jerks when i punch it wide open and in first gear, slow increase toward the 8000 mark doesnt cause it.
 
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Old 01-05-2013, 11:42 PM
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Have you looked into your ignition system. It kind of sound like you are describing a misfire under load. It could be an old plug or plug wire breaking down.
 
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Old 01-05-2013, 11:46 PM
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Originally Posted by 74demon
Have you looked into your ignition system. It kind of sound like you are describing a misfire under load. It could be an old plug or plug wire breaking down.
well it only does it in first, in neutral it doesn't, and if i hold the throttle it continues on. Its consistent almost every time. every so often i get lucky. I feels like something in the tranny gives up. Or maybe i break the rear tire for a split second. But it very well could be the ignition. The plugs are clean and new, i just would wonder why it is always at the 8k-9k range
 
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Old 01-05-2013, 11:53 PM
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Plug wires can misfire under loads and at higher RPM more. If they are old, I'd replace them anyway, or do the coil pack mod.
 
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Old 01-06-2013, 03:42 AM
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Default +1

Originally Posted by 74demon
Plug wires can misfire under loads and at higher RPM more. If they are old, I'd replace them anyway, or do the coil pack mod.
+1

once you have done the basic electrics I hope it will cure your problem.
 
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Old 01-06-2013, 04:39 AM
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8000 is where the max torque starts to come in - could it be a partial blockage in the fuel line, as opposed to an electrical problem ? Sometimes the petcock fuel filter can clog up - best answer is to reverse flow the fuel (a bicycle pump full of fuel) pumped up the line would soon tell you - if the blockage goes away for a time, drain the tank and clean the petcock.
Second option, could be a partially blocked tank breather. Try running the bike hard with the cap open (for a short time) and see if this helps. If it does, clean the tank breather.
 
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Old 01-06-2013, 09:43 AM
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Check float levels in the fuel bowls - sounds like she's not getting enough juice through
the main jets at high rpm - imo
 
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Old 01-06-2013, 11:00 AM
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Originally Posted by Shadow
8000 is where the max torque starts to come in - could it be a partial blockage in the fuel line, as opposed to an electrical problem ? Sometimes the petcock fuel filter can clog up - best answer is to reverse flow the fuel (a bicycle pump full of fuel) pumped up the line would soon tell you - if the blockage goes away for a time, drain the tank and clean the petcock.
Second option, could be a partially blocked tank breather. Try running the bike hard with the cap open (for a short time) and see if this helps. If it does, clean the tank breather.
I'll give this a whirl. Maybe it's the fact I hate any type of electrical issues and that's why I deny it in my mind. Thanks guys I'll check the fuel lines out. I know it can breathe though cuz if you look at one of my pics, you might be able to see the gas cap has a wonderful sliding bolt lock for a bathroom stall courtesy of the previous owner and It never quite seals right.
 
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Old 01-06-2013, 11:16 AM
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I also am thinking fuel delivery. I'm thinking jetting.

What kind of air filter and pipe are on the bike?

The thing is, in 1st gear there is not the load on the engine as in the higher gears. Leaky head pipe could cause same symptoms.
 
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Old 01-06-2013, 07:13 PM
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Ok after riding today im fairly certain the engine is not the cause, i paid close attention to the rpms and feeling the engine you could say. The engine is consistent, and when something breaks loose and kicks back in it feels like pulling the clutch in and letting go again. The rpms kick up then back down. maybe like it finds itself in a false neutral for a split second. Then i was coming out of a turn from a intersection and opened it up and i was still in a light lean when i hit 8500 and it gave then kicked in, spinning the back tire a little. This is the first time i was in a light lean when it happened so im wondering if my rear tire is the cause. I have the suspension a little tight. It is a Shinko 005 tire.
 


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