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Just a week ago I noticed in my motorbike unstable rpm, +-300rpm. But today I found that the idle rpm are below 1000rpm, at some points around 500rpm (Normally is 1500rpm). I'm due for the annual maintenance next month and I'm not sure if this problem is because of a sensor, dirty fuel injectors or anything else. Any ideas?

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What year is that? How many km? And which throttle bodies does it have (Keihin, Mikuni, etc.)? Could be as simple as proper idle screw adjustment. For instance, on my 250 Zook with Keihin throat that screw can loosen up a bit, which would cause lower RPM, and even stalling at times, for which EFI cannot compensate (I have 32-bit ECU, like on the big GSX-Rs). – theUg Nov 8 '13 at 6:32
Hi @theUg my motorbike is from 2008 here is the wikipedia entry about it: I think it's all electronic, so I don't think there's a screw to adjust the idle (Like I had in previous bikes). Thanks for your comment :) – SERPRO Nov 8 '13 at 10:00
vacuum leak or dirty throttlebodies if its an injection could do it. – Mauro Nov 8 '13 at 15:54
I'll check that with the mechanic.. I also found in the manual (Page 2-15) how to change the idle speed.. So I will try that too.. – SERPRO Nov 8 '13 at 16:03
up vote 2 down vote accepted

Suzuki garage found the issue. Broken hose going to the engine was the problem, nothing major.

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I'm having pretty similar issue you have as well. When cold start no issue at all. After 10-15 mins ride idling will sudden drop below 1K (my default idling is 1.3k). if i let it rest for 20min and continue the issue gone. May i ask which broken hose did your suzuki garage change? – user9977 Apr 2 '15 at 6:05
It was over the radiator area near one of the sides (I don't remember which side was it). It was very easy to see with normal daylight – SERPRO Apr 2 '15 at 9:54

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