Ok...So i scoured the Service manual...and could not find the answer i needed...
So maybe one of ya know the answer
The manual states the fuel pressure should be 50 psi at idle....now is this pressure supposed to get higher with the more throttle you give it...or is it just supposed to stay at 50 psi?
Fuel pressure does not get higher as you rev it, unless the system is returnless. But, ours is not, and in reality fuel pressure goes down as the RPM go up. The manual talks about 50 PSI of static fuel pressure, that is, at idle. If you were to test it, it would probably go down to 38-40 PSI at redline.
I thought ours was returnless?....it terminates into the fuel rail and then to the secondary rail and thats it....no fuel comes back to the tank, my R1 had a return......
Are they? Crap, its been a while since I've been under there but I think I remember seeing a fuel pressure regulator but on a 929...oops, my mistake.
Anyway, if there is no return, then there is possibility that the ECU regulates pressure by voltage to the pump. But for some reason this seems unlikely...sorry I can't be of more help.
usually only turbo or supercharged vehicles have a fuel pressure that goes up
it is either a rising rate meaning that if the regulator is 12:1
the fuel pressure goes up 12 psi for every 1psi of boost
or its a matching rate or 1:1
injector rail/supply pressure usually is consistent thru rpm range and the pulse width is increased(more on time) as rpm and fuel needed is increased.would be hard to map for high rpm without having a known/presumed supply pressure present.pressure is probably regulated in the pump unit. return systems usually have a regulator that is activated by intake vacum ,when the throttle is opened and vacum is lost,pressure goes up to add more fuel until vacum is stabilized again (load decreases)
the manual states if fuel pressure too high to replace the fuel pump,would support the thought that pressure is regulated by the pump itself.
How would one adjust pressure up a slight amount? Replace pressure regulator in tank? If so, does anyone know where to get one compatible with a little higher pressure?
Im frustrated by this omission in the manual....i would hope that they would be more explicit with the values needed to keep the bike from blowing up.....50 PSI is what mine reads at any throttle position ...It does not vary at all, only when the gauge heats up in the sun it reades like 3 lbs lower...once it cools off while riding the gauge reads 50PSI all day long.....I am thinking it should raise or lower depending on the load.....
Why? What is wrong with a constant pressure? Having different pressures would mean that the injectors would behave differently and the atomization would vary. Would you rather have full pressure at isle and have it drop off at higher RPM’s. It would also be something else to break.
Not necessarily. As long as both sets of injectors are getting the proper volume of fuel, the engine should be fine. Pressure is what allows the fuel to leave the injector as a fine mist, enhancing atomization as it meets the incoming air.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Honda CBR 1000RR Forums
2.5M posts
50.9K members
Since 2003
A forum community dedicated to Honda CBR 1000RR motorcycle owners and enthusiasts. Come join the discussion about troubleshooting, performance, modifications, classifieds, maintenance, and more!