View Full Version : Stuttering and backfire


CamScooby
15 December 2003, 11:00
Hi all,

Sorry for the long post. I’ve had the SV650S for a few months now (great fun) and just been lurking until today. It’s a 99 with 19K on it.

I had some jerking and shuddering about a month ago and after reading the archives, put it down to water in the fuel and drained the carbs and tank and all seemed well. I made doubly sure that the drain tube wasn’t kinked when I put it back together.

On Sunday it came back when I was in Leicester and a few miles from home :-( Same symptoms wouldn’t rev over 4000 (except occasionally with full throttle it would start revving up to 8 before I changed up – didn’t want to go all the way in case something let go) and was shuddering and lurching forward and back.

Got the AA man out as my battery was sh***ed and wouldn’t start it. He checked some of the electrical connections and they seemed fine, and as usual with this sort of thing it was revving absolutely fine in neutral, all the way up the range to 10. As soon as I went round the block it would jerk again at 4000.

The bike always has a waterproof cover on it and I’ve only washed it carefully once since I’ve drained the fuel (and as I said, there’s no kink in the pipe). Any ideas as to why it would do this only at 4000 regardless of what gear you’re in. The AA man suspects electrical (possibly the ignition controller as both cylinders seem to be affected).

Your help is much appreciated as it’s taking the shine off the bike at the moment.

TIA

Gareth

EvoBarry
15 December 2003, 12:50
Just a longshot, but do SVs have carb icing problems? I know Kawa's suffer from it occasionally, altho mines been fine so far.

DRUNKNORGY
15 December 2003, 19:14
Has the bike been stood for a long time, I had a 250 a few years ago, and left it for a while. The jets silted up with petrol deposits (like limescale), and stopped it reving out. I cleaned them and it sorted it out.

CamScooby
16 December 2003, 10:09
Thanks for the replies.

Re carb icing, some do suffer, but the whole of the engine & carb unit was well up to temperature, so i don't think it was this.

As for standing around, it had only been a week since the last trip.

Plan of attack at the moment is to check & clean all of the connections in the ignition circuit, then start by cleaning out the carbs if this doesn't work.

Gareth


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