My bike does this too, on start-up it does not have a high idle. The idle is 1200 rpm at start-up and the same after it has warmed up.

Ordered a new FPR for mine to try, have heard it may be due to our hot weather here....but my brothers GSXR runs @ 2500-3k rpm at start up and drops to 1200 after a few second which is what all my other F4i's have done.

Hoping the FPR fixes mine but will be keeping up with this thread in case it doesn't and someone else has found a fix.

 

bigboi you might be on to something with the hot weather thing. My bike was usually garaged in temps. lower than the outdoor temp, but since I have been storing mine outside under a cover it idles low on cold starts. One time it stalled after startup and the FI light was on. I thought maybe it was bad gas, but the bike runs good once moving and idles at 1300 when warmed up.

Spartan where are you located? Did this just start when the weather got hot and do you store your bike outside in the heat?

 

Changed out my FPR just now and it made no difference. Idled it up with the adjuster and it just stays idled at where you adjust it. It is easily mid 90's by 10 am here and no lower than 75 so that may be my issue.

Will find out at the end of October when the temp starts to drop I guess lol. As long as it keeps running good I'm happy.

 

I had similar problem before. But my FI light shows MAP error so I don't know if this applicable to you or not, but might worth a try.

At that time my vacuum hoses that runs to MAP sensor (from the 5 way T throttle bodies) was partially blocked.

You could check all your throttle bodies vacuum hoses whether they are blocked. I just blew some air from my mouth feel the flow.

Good luck

 

Hmm this pretty much started when we started getting hot weather too. Weird, maybe it is from that. Thanks for sharing what you guys have found in here, I appreciate it a lot, and thanks for saving me $70 on the FPR! Also important update, today I went out to go riding to try out my new leathers on the CBR, started it, it idled under 1k, continued to idle down, then died and won't start again. I killed the battery trying to start it, primed the fuel pump multiple times, etc, it absolutely will not start. Was raining all night though and sitting outside, doubt that could cause this but what do you guys think? On a side note I took my ninja out riding since it would at least start and it died twice during our ride and took it's sweet time before it would start up again, but it's carbed and has always hated moisture.

 

A little update, still no luck on the bike. I got it to start by taking the airbox off and running it with just open throttle bodies, go figure. Since then it's ran slightly worse than before it decided to not start, but it runs.

I've narrowed it down to the map sensor (I think) as that made the biggest difference in whether it would start or not. It doesn't throw any codes though, unless I unplug any of the sensors then it throws the corresponding code. The weird thing is the codes don't go away until I wipe them, but when I wipe them then the FI light stays on solid if I short out the diagnostics thing under the seat until I trigger another code. I'm pretty sure it isn't supposed to work like that so maybe I just have a retarded ECU, which could be part of the problem.

I ordered a new map sensor and it didn't help at all either. Next up is to check all of my vacuum lines and after that I'm kind of lost on what to do. I doubt it has to do with horribly misadjusted valves or my bike being out of time, those things don't just happen overnight and when it's warmed up it runs amazingly and I managed to get a 3.5 second 0-60 and under 7 second 0-100mph which shows the bike is performing well despite having issues. Also my spark plugs are coated in carbon and that has to be from a fueling issue.

Also it should be noted that the map sensor I bought is from a honda/acura car. The part number is almost the same and the connector is the same, saw that it would work on another forum. Cost me $17 vs $140 for a new one, and that's a dang good thing considering it didn't help.

Anyone think of anything else to check? I just want to ride my bike lol.

 

Have you actually checked the vacuum line? Sometimes the problem could be very simple like mine, the hose to MAP sensor was blocked. Good luck

BTW, can you tell me your MAP sensor item code? I'm very interested at $17 MAP sensor

 

No not yet, I think I'm going to just replace them all. I don't have a vacuum gauge unfortunately. Is there a way I can buy all the lines together, or could I just buy the correct size hoses and cut them up myself?

The part number is 079800-3000 for the one I bought (off ebay), the part # for the F4i one (which is the same model as almost all Honda bikes from the same time) is 079800-5780. I couldn't find any used ones for our bikes so I just got the car one, exact same connector the only physical difference is it has two mounting holes vs one. The only other difference is the motorcycle version says "5V-38" the car version says "5V-30," the 5V means 5 volts of course but I'm not sure what the 38/30 stand for. Either way the bike runs just as terribly with either sensor lol.

 

I just blew air from my mouth It was so blocked I was able to tell immediately. Maybe you can try that first before buying any gauge.

I have replaced my hose too. The came in bulk, 1 metre. You'll need 1.6 metre if I remember correctly if you want to change all lines. You need to cut them yourself.

 

Which hose(s) did you test? all of them? I could feel vacuum from the hose that attaches to the map sensor with my finger but it wasn't much, could definitely be a blockage somewhere. I believe that hose goes into a 5 way splitter that goes to each throttle body.

Thanks for the hose info, do you know the exact dimensions for them? Did you just get them at a hardware store? Thanks!