Momentary loss of power pulling away from a stop

[moonwalker]

Hi All,

Excuse the new post, I couldn't find a match from previous searches. My 2005 GS500F has recently developed a problem that has given me a couple of scares.

Randomly, it has been momentarily losing all power as I pull away from a stop. This has occured after 10 minutes of riding so its not cold engine related. The RPM needle has a fit. I'll be pulling the usual graduated 3-4 RPM throttle as I engage the clutch and pull off, but suddenly the needle will immediately flick all the way down to zero and then a millisecond later flick back up to where it was before (sometimes twice in succession). However, in its momentary loss of power I've had the engine die on me a couple of times and I almost stalled pulling out into a major road - as it was the oncoming truck got much closer to me than was comfortable... Where it hasn't died on me it often cuts back in at 5-6RPM where I've rashley poured on the throttle in a vain attempt to prevent it from dying. I've upped the idle RPM to 1800, this seems to have helped prevent it conk out when the RPM needle (and whatever the underlying cause) flips out, but theres still no pattern to the randomness of its occurence - except that it only occurs when I'm pulling away from a stop. Once I'm going, the bike behaves fully as expected.

I'm not techie enough to strip my bike, but it'd be useful to give the folks I pay to do it a few pointers. Does it sound like dirt or water in the carbs/fuel? I hadn't used the bike for a couple of weeks before it first started happening so its possible condensation or dirt might have got in there, but I don't leave it with less than half a tank. I've added some additive to the fuel (first time ever...) and will add some more on the next fill - maybe I just need to flush it through - but I'm a bit concerned it could be more serious and I'd rather not have it cut out on me at the wrong moment...

Cheers

[Dizzledan]

how many miles since the last carb clean? It sounds exactly like one of your jets is clogged completely, and the loss of power is no gas getting into the engine. Last time you changed your air filter?

I would start easy with inspecting your air filter, and then run some seafoam in your gas tank to see if that helps the issue.

[moonwalker]

Thanks for the response. I don't think the carbs have ever had a proper clean if I'm being honest...

I'll start with the air filter as you suggest, but if work does need to be done on the carbs, do you know how many hours it might take? Trying to guestimate rough cost before the mechanics take me for a sucker!