Pointy cutting out on downshift.

[Surfjayce]

SV650SK5, just had new tyres and new fork stanchions fitted so decided to go for a long ride to settle everything in, about 25 min into my ride the bike started cutting out when down shifting for islands or junctions and wouldnt start again without giving it some throttle, i know its a little vague but any suggestions on what could cause this? just trying to narrow stuff down.

cheers

to note:

There was half a tank of quite old petrol in the tank but was riding fine, then i topped up with fresh petrol and thats when this started

The oil and filter were changed last year and havnt done many miles

[Bibio]

do you drive a diesel car?

[Surfjayce]

LOL! i didnt put deisel in by mistake :P

[Surfjayce]

Anyone?

that old petrol will be fouling up your plugs i expect, try a new set once the ols fuel is done, or try fuel stabliser mabie

[jambo]

What's your idle speed currently set at? (Should be ~1,600rpm)

When you start the bike from cold does the auto fast idle cut in for a bit and then bring it down to the normal idle speed after a minute or so?
Have you bypassed the clutch switch?

Jambo

[Surfjayce]

Haynes says idle should be at 1100-1300 so thats what its set at, and the bike pretty much settles at idle right away, i wouldnt even know how to bypass the clutch switch.

The fouled plugs sounds plausable from the old fuel, im not too clued in on stabilisers, so any suggestions on where to buy it or what brand would be cool, and yeah a plug change after this tank of fuel is defo on the cards

cheers for the replies guys

[Jayneflakes]

The reasons for this could be numerous, grit in the sidestand switch making it flicker as you shift down, dirty contacts somewhere, dodgy wires, changing gear too late stalling the engine, connectors not put back right, water in old fuel wetting the plugs slightly, muck in the tank getting caught in the throttles, worn out or dirty spark plugs, a mouse nest in the airbox...

If it worked before you changed the fork legs, then something you have moved may be playing up with a dirty connection. The variables are endless and so you just have to start with the simple ones first and work through them in a methodical way.

[jambo]

Clutch switch:
If you can start the bike without the clutch pulled in this has been bypassed, perhaps by a previous owner, no idea how long you've had the bike.

From my own experience 1,100 rpm is low enough to cause issues stalling with a little clutch drag on downshifts. 1,500 is where I'd set it.

The fact you've changed your fork legs isn't an obvious pointer, but the fact you've said the fuel is old suggests you've not been riding it of late. It's got colder and a lower than ideal idle may have been fine in summer, but less OK now the temperature's dropped. If the clutch is not adjusted perfectly / dragging slightly these things all add up.

Jambo

[Surfjayce]

The Garage changed my forks so im pretty sure that's not gonna be a factor, the clutch is definitely not bypassed, iv had the bike for 5 years now, but all the suggestions are good good, il pick each one appart 1 by 1.

again cheers guys, giving me alot to check out