I know this may be a common topic but I'vee searched this topic for a month and have yet to find out my prob. I have a 2001 CBR 929RR and the issue I'm having is power loss/bogging at 7000rpm and rpm's don't climb higher. I've recently replaced fuel filter, had the valve clearance checked, made sure cams hasn't jumped a tooth, cleaned air filter, new plugs, seafoam treatment, fresh oil, and fresh gas. Flapped mod done, htev wired open, and flashing no codes. Any other recommendations?

 

Did this start all of a sudden, or right after you did something to it?

My first thought is that the HTEV is frozen, but you say it's wired open. Check that it still is with the index mark to the 180 position.

Fuel pressure?
TPS crapping out?

 

Yes sir, still with the 180. FPR is in working order as well. Its pretty much been like this since i bought the bike. Tried everything i can think.of to remedy this.

Could this be a symptom of the TPS?

 

The TPS is a variable resistor. They can get dead spots in them. Rev it without a load slowly. If it's has a bad spot, it will sputter as you cross it.

Check your fuel pressure. A pump with low output, or an over regulating regulator can do what your describing. Make sure the vacuum line to the FPR is hooked up and from the correct source. In fact, check all the vacuum lines to make sure they're right. MAP sensor line too...

 

A little success bro. While checking all my vacuum hoses, I've discovered a mistake that the Honda made when i brought my bike in for a tune-up a couple months ago. Apparently they've crossed the vacuum hoses coming out of the pair valve solenoid to the air cleaner. After making the change now I'm achieving higher rpm's, but now Im only topping out at like 125 b4 it starts losing power....

I guess next i should try a new fuel pump? If anything I'd rather it be the fuel pump rather than a worn piston ring or something deep inside of the engine....

 

Fuel pumps are not cheap. Check the pressure first.
Try pinching the return line and see if its better.

 

A few months ago I've tried to get it dyno'd and they told me that it kept losing fuel pressure on the top end. they tested it and the results matched what the manual specifies. But I guess under a load it underperforms? Unfortunately, they weren't able to dyno it. That's when i began troubleshooting.

Could the pair valves have gotton damaged because of the crossed hoses?

 

The fuel pump doesn't know load. Load demands more fuel, the pump can't keep up with the fuel demand. Could be a weak pump or pressure regulator. I'd start with the regulator before doing the pump. FPRs are cheaper, easier, and more common to fail. Even if the FPR is not the problem, it's good to have one. You will need it eventually.

Pinching the return hose will not let the FPR send fuel back to the tank, thus increasing the pressure to max pump output. If it runs better, the FPR is relieving the pressure too much.

 

Ok, will try that tomorrow. Thx bro, I'll update afterwards.