Can't figure it out!

[fastbike1300]

When I ride I get about 15, 20 min into it and while cruising 4500 5000 RPM'S, it feels like I lose power and the engine misses. This does not happen all the time and sometimes it just goes away. I have no mods 21,500 miles on it. It does the same thing at lower RPM'S also once it starts.

I have checked the tank vent hose and have done all the periodic services. Help! This is bugging the crap out of me!

Oh, when I wick open the throttle, it still pulls hard no misses pulls to red line and I did 180 yesterday if that matters.
thanks again.

 

[MET]

Check your throttle bodies and make sure they are all in sinc. Also start with the easy things like the airfilter. Could be clogged or it sucked something in? Still have the screens on the front?

 

[hank]

21,000 miles. maybe time for a good tune up.

 

[fastbike1300]

ninja eater I did the 15000 mile check myself including the valves. It would do it sporadicly before the 15k service and at first I thought it was bad gas. I guess I go to the manual agian and check the t-bodies. The only thing I did not do. by the way any suggestions on doing the t-body check?

thanks FB

 

[cache]

whatever it is, its a closed-loop circuit problem. when you go openthrottle, you are in open-loop just as when the engine is cold and not up to normal operating temperature. The fact that you get into about 15+minutes of riding tells me that once it gets to normal operating temperature, you get problems. That can put several sensors and sending units into play.

1) check sensors like coolant temp sensor, airflow sensor, etc.
2) check your fuel... crappy fuel will foul when engine is warm and not under load
3) check spark plugs for same reason as fuel problems

Primarily the problem will be in what the normal garage-tech will not know how to diagnose. When the engine is at normal operating temperature, and in closed-loop operation, many sensors and sending units willl come into play. Even in closed-loop operation, when you go to wide-open-throttle, some of the systems are bypassed and will not effect performance.
Your symptoms including being able to haul ass with no problem, tells me you have a bad sensor, sending unit, or injector malfunction. Sorry to not help you with anything but confuze you, but you are not riding a Honda CT90 either.

Please let me know if your bike is under warranty, or if you plan on fixing this yourself.

cache

 

[Kerberos]

could this be the sensor that is in the airbox for temp? you know, the one that others have removed and relocated into on of the ram air tubes?

 

[Narcissus]

Check TPS

 

[fastbike1300]

Cache thanks for the info! O.K. yell at me but I did not replace plugs at 15k like I should have. I will be fixing it myself so any help you can provide will be great!

Hey K I have not made any mods to the airbox but I will see if the sensor is connected properly. Would the speed sensor have anything to do with it? I HATE diagnosing problems! I put about 100 miles on it every day. Got to get it fixed.

thanks

 

[cache]

Check TPS

If the Throttle Position Sensor is the culprate, you will notice problems at any temperature at the same throttle opening every time, ie: half-throttle would act up cold or warm, etc.

Maybe Narcissus has prior experience with this symptom, but I would assume a temperature sensor, or something that tells the ecu to be at normal operating temperature, would cause a warm-engine driveability issue.
You don't encounter any of the symptoms when the engine is cold while you are riding? or is it a constant issue?