Throttle weirdness

Just been out for a bimble on my 2002 naked curvy SV650 (standard, except for the Carbon Can Co Oval end can). By the time I wanted to come home, I was a bit lost, so headed for the only town name I recognised: Newbury. Eventually that got me onto the M4, and then home on the A34 - a blast of about 30 miles during which I didn't drop much below 70mph.

As soon as I got onto slower roads, the bike started behaving weirdly - more pops and grumbles than I'm used to, and the engine note somehow didn't sound right. When twisting on the throttle the revs would increase but somehow the bike wasn't pulling, until there was a pop and I'd lurch forward. Similar stuff on the overrun, so I was being jerked forward and back. It wasn't constant, and didn't seem to last very long: it didn't do it for the last few streets (but I live very close to the A34, so can't say it wouldn't have carried on had I gone further). Any ideas what's going on? (Could it be the fabled carb icing - not that I know anything about that, it's just something I've heard discussed on here a few times?)

Oh, and hello BTW - I introduced myself in the Thames Valley section, but this is my first post outside there.

Full disclosure: I dropped the bike from stationary earlier in the day (documented in the Thames Valley section), but don't think this weirdness would be related - I'd done 50 miles since then without a problem.

[Biker Biggles]

I assume it was p1ssing down while you were out?It was here,so have you considered water in the front plug?

Originally Posted by Biker Biggles

I assume it was p1ssing down while you were out?It was here,so have you considered water in the front plug?

No, it was dry all day for me (though the roads never fully dried out from overnight rain). Thanks for the suggestion, I'll try and have a poke round the front plug, but I've been out in far worse without problem.

[yorkie_chris]

Running rich can give symptoms similar to what you describe, check the choke plungers are moving freely.

Originally Posted by yorkie_chris

Running rich can give symptoms similar to what you describe, check the choke plungers are moving freely.

I'll have to look through the Haynes to work out how to do that, but will give it a go (or find someone that can). Thinking about it, the idle is often 'lumpy' (rev needle bobbing up and down, occasional pops), especially while on the choke when starting from cold. I assumed that was normal (this is my first bike, and I've only had it two months), but could that be a related symptom?

[yorkie_chris]

Quite possibly. How does the choke lever feel? Is it smooth or lumpy? Sounds like a wierd question and you will probably not know what it is supposed to be like until fixed.

Haynes tells you sod all of use.

Originally Posted by yorkie_chris

Quite possibly. How does the choke lever feel? Is it smooth or lumpy? Sounds like a wierd question and you will probably not know what it is supposed to be like until fixed.

You know, it's not the smoothest lever I've ever pulled. For a cold start, I tend to pull it right on, hit the starter, then move the choke back until the revs are 2000-2500rpm. As it warms up, the revs climb a little bit, so I keep knocking it back to keep the revs in that band, until ~30-60s are up. Each one of those adjustments is a little fiddly, a case of "a little more, a little more, a little more... no, too much". Is that the sort of thing you're getting at?

You've got me (a bit) worried now . I might have to try and arrange for a Thames Valley bod to come try it out and tell me what's normal and what isn't...

[yorkie_chris]

It's a common problem and easy to sort. It is a bit fiddly to use, but sometimes a knackered one will feel like it's full of sand.