nybryan Posted May 1, 2010 Share Posted May 1, 2010 Seems my bike developed a bit of a flat spot at 5200 rpm since I added a K/N airfilter. Bikes is stock besides the filter. I never removed the inner gasket from the air box when i added the K/N. Is this a common problem. Maybe the filter is not sealing right. Other thoughts before i go back to stock. It only happens at steady throttle, a flat spot hick-up as I'm chugging along Quote Link to comment Share on other sites More sharing options...
brianmacza Posted May 1, 2010 Share Posted May 1, 2010 Is your bike injected or carb? My '97 LOST the 5500RPM flat spot when I put the K&N and slipons on it - even with stock pipes the flat spot was noticeably better. You say that its more prominent at a steady throttle - is the engine hunting up and down on a fixed throttle? Surging? Quote Link to comment Share on other sites More sharing options...
nybryan Posted May 1, 2010 Author Share Posted May 1, 2010 injected bike and yes surging is more accurate. When i put in the K/N airfilter on my 02 the lid of the airbox wouldn't close. It sat up about a 1/4 inch. slow tightening the screws closed it down. I later learned that there is a gasket inside the airbox that should have been removed when i added the K/N. I am wondering if the K/N airfilter is not position correctly and letting some air leak by. Could this be causing the situation im talking about? Quote Link to comment Share on other sites More sharing options...
Flitemdic Posted May 1, 2010 Share Posted May 1, 2010 injected bike and yes surging is more accurate. When i put in the K/N airfilter on my 02 the lid of the airbox wouldn't close. It sat up about a 1/4 inch. slow tightening the screws closed it down. I later learned that there is a gasket inside the airbox that should have been removed when i added the K/N. I am wondering if the K/N airfilter is not position correctly and letting some air leak by. Could this be causing the situation im talking about? So I've heard. I have a carby bird, so it's a little different, but others who have FI have noticed this problem before. Quote Link to comment Share on other sites More sharing options...
XXTi Posted May 2, 2010 Share Posted May 2, 2010 The XX I used to have ran better with an OEM filter than the K&N that came with the bike. Quote Link to comment Share on other sites More sharing options...
Herc driver Posted May 2, 2010 Share Posted May 2, 2010 I have a carbed bird and just changed out the OEM filter with a K&N and noticed I have more torque but there's definitely a very pronounced flat spot around 5500. I'm curious if the increased airflow on the carbed models require a re-jet. Quote Link to comment Share on other sites More sharing options...
brianmacza Posted May 3, 2010 Share Posted May 3, 2010 I have a carbed bird and just changed out the OEM filter with a K&N and noticed I have more torque but there's definitely a very pronounced flat spot around 5500. I'm curious if the increased airflow on the carbed models require a re-jet. Do you still have your stock pipes on? The move to slipons cured my flat spot. Made it noisy as hell tho... Quote Link to comment Share on other sites More sharing options...
Herc driver Posted May 3, 2010 Share Posted May 3, 2010 I have a carbed bird and just changed out the OEM filter with a K&N and noticed I have more torque but there's definitely a very pronounced flat spot around 5500. I'm curious if the increased airflow on the carbed models require a re-jet. Do you still have your stock pipes on? The move to slipons cured my flat spot. Made it noisy as hell tho... Yeah, still have the stock cans. I don't have any particular interest in changing them out either, but if you also had the flat spot that resolved itself with new cans, I think it pretty much means a re-jet if I want to keep stock cans. Quote Link to comment Share on other sites More sharing options...
REXX Posted May 3, 2010 Share Posted May 3, 2010 The K&N made my fuel mileage terrible and felt like less power with my butt-dyno. Put the stock filter back in and back to normal...it's a '99 with Scorpion slip-ons. Quote Link to comment Share on other sites More sharing options...
Banshee Posted May 3, 2010 Share Posted May 3, 2010 On my '98 carbed bird, a K&N + Yoshi slip ons (& later, '99 headers), cured the flat spot. And they weren't too loud. With the injecteds, the K&N is in a flexible surround that replaces the O-ring in the airbox lower. The K&N for the carbed birds, is in a hard surround that uses the airbox as is. Quote Link to comment Share on other sites More sharing options...
nybryan Posted May 3, 2010 Author Share Posted May 3, 2010 so on my injected bike the problem is likely that i left the o ring in the airbox and have a wierd seal. I'm going back to stock Quote Link to comment Share on other sites More sharing options...
BobZ Posted May 4, 2010 Share Posted May 4, 2010 so on my injected bike the problem is likely that i left the o ring in the airbox and have a wierd seal. I'm going back to stock If I were you I would just use the O-ring that came with the K&N and take out the one in the airbox...you won't have any problems, trust me I have walked in your shoes! Quote Link to comment Share on other sites More sharing options...
brianmacza Posted May 5, 2010 Share Posted May 5, 2010 trust me I have walked in your shoes! did they also have a flat spot? Quote Link to comment Share on other sites More sharing options...
nybryan Posted May 5, 2010 Author Share Posted May 5, 2010 pulled out the lower o-ring and now its working right. Thanks for the advise bryan Quote Link to comment Share on other sites More sharing options...
Banshee Posted May 24, 2010 Share Posted May 24, 2010 You are welcome. Remember, free advice is worth every cent! Quote Link to comment Share on other sites More sharing options...
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