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2008 CBR 1000RR idle

orang.narsis

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Joined
Jul 1, 2025
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My 2008 CBR 1000RR (which I recently bought for really cheap) has this weird idle issue. When the bike is cold, it idles high around 2,100 rpm, which is normal. But once it warms up to about 90°C, it still stays at 2,100 rpm like it's cold. The only way to get it to drop to around 1,500 rpm or lower is to let it off for a while, wait like 8 minutes or so, then restart. I already brought it to my mechanic but even he cant figure it all out.
 
It sounds like you might be dealing with a classic issue related to the idle air control valve (IACV) or maybe a fast idle problem. If the valve is stuck open, it can cause that high idle to persist even when the engine gets warm. I had a similar experience with my old 954RR, and a simple cleaning of the IACV did the trick.

While you're troubleshooting, it could also be a good idea to check for any vacuum leaks or a sticky throttle cable. By the way, has your mechanic taken a look at the IACV or the throttle position sensor yet?
 
My 2008 CBR 1000RR (which I recently bought for really cheap) has this weird idle issue. When the bike is cold, it idles high around 2,100 rpm, which is normal. But once it warms up to about 90°C, it still stays at 2,100 rpm like it's cold. The only way to get it to drop to around 1,500 rpm or lower is to let it off for a while, wait like 8 minutes or so, then restart. I already brought it to my mechanic but even he cant figure it all out.
I'm with @firebladefan. Have you or your mechanic checked the IACV or its associated wiring thoroughly? Sometimes they can stick or have intermittent electrical issues that aren't immediately obvious. Also, a slightly off engine temperature sensor reading, even if not fully faulty, could potentially trick the ECU into thinking it's still cold. The other, maybe faster route is to consult another mechanic for second opinion?
 
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