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-   CBR 929RR (https://cbrforum.com/forum/cbr-929rr-20/)
-   -   Under load, 7000 max rpm???? (https://cbrforum.com/forum/cbr-929rr-20/under-load-7000-max-rpm-148069/)

92neezy 07-17-2013 10:04 AM

Under load, 7000 max rpm????
 
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?

74demon 07-17-2013 11:57 AM

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?

92neezy 07-17-2013 12:11 PM

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?

74demon 07-17-2013 12:23 PM

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...

92neezy 07-17-2013 03:12 PM

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....

74demon 07-17-2013 03:24 PM

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

92neezy 07-17-2013 04:27 PM

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?

74demon 07-17-2013 04:43 PM

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.

92neezy 07-17-2013 05:27 PM

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


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