What the hell is going on with my bike?

[ranathari]

My bike's stalling for no good reason while I'm riding.

Every time I brake and pull the clutch in to change down to first, the bike stalls effortlessly. Because it's raining outside, I assumed it was because there's no fender extender fitted right now, but the bike fires up first time after it stalls, so I'm guessing it's not a spark plug problem. The bike otherwise runs fine until it stalls and I'm not keeping it in too high a gear or anything else that could stall it (trying to say it's not a problem between the seat and the throttle!)

I have no idea where to begin so I'm planning to take it to the local garage once the rain stops (not keen on having it stall in the middle of a blind bend again).

It's an '01 SV650S, minimal modifications from standard (just an exhaust).

[petevtwin650]

So does it stall when the bike isn't in motion and you apply the brakes or clutch or both together?

[ranathari]

Nope, only when the bike's on the move. It's really difficult to reproduce the problem because the bike stalls painlessly - I'm riding along, pull on the front brake to slow down, pull in the clutch and roll off the throttle to change gear, let the clutch out and open up the throttle only to find the bike's not responding. Look down and the red oil light has come on (like the bike's only just been turned on but the amber light's gone out, indicating you can start it). If I pull the clutch back in and hit the starter then the engine starts first time. It's also erratic; it doesn't stall every single time I change gear and I can't identify a common factor from each time it stalls.

Just fyi, I'm deaf which is why I can't hear the engine stall. I'm guessing I can't feel it because it's stalling when the clutch is pulled in and there's less vibration.

[petevtwin650]

Firstly not a problem solver but a help, blip the throttle on the downchanges.

Is the tickover set a bit low or maybe one of the chokes are sticking.

[Steve_God]

Have you altered your throttle cables recently?
I had a similar problem when I took them out to lube them. I put them back in not as they were before, and it meant that when braking, with my body weight put forward, I was turning the throttle just a little past its rest point, and causing the throttle to die down and would occasionally cut out.
Might not be, but it's a possibility.

[dirtydog]

I had a similar problem a while ago which was down to a stuck choke. It would stall as i slowed and pulled the clutch in at traffic lights, roundabouts that sort of thing

[ranathari]

Definitely not the throttle cables - they were replaced a couple of months ago and have been great since.

How can I go about checking the choke? It's completely off as far as I can tell. Also, how can I increase the tickover?

[dirtydog]

My choke lever appeared to be off as well but it was the cables under the tank and the plungers on the carbs that needed freeing off. So it's a tank up job for the cables/carbs.

[neilfab]

I've had this on my pointy. In my case I 'uped' the idle speed to about 1300/1500 and the problem went away.

[flymo]

check out the float levels for the carb fuel bowls if you get a chance, if they are too low you might get this symptom

[ejohnh]

The idle speed adjuster is on the rider's left hand side. A round adjusting wheel/knob just inside the the frame area about vertically in line with the two frame welds. Your clutch cable might be obscuring it. It connects via a cable to the actual carb assembly. turn it clockwise until your idling revs get up to between 1300 and 1400 rpm. Make sure they don't decrease if you roll the throttle hard shut. See if it still cuts out.

[ranathari]

I increased the idle speed before taking the bike out and it seems like the problem's gone for now. I'm not convinced it was a permanent fix so once everything dries out, I'm going to get the tank up and check out everything you guys have mentioned.

Thanks for the incredibly speedy and helpful advice, guys!

[Al_Sweetman]

I have the exact same problem with my pointy - used to do it every single time I pulled up or slowed down - a nightmare especially going onto a busy roundabout and it suddenly stalls! It's not a stall per-se, but almost like the bike has it's ignition turned off - mine wasn't at all jerky, it just plain died!

I assumed it was because it was due a service, and I did the throttle cables (rather, throttle synch) at the same time - it's made it better, but not perfect. In my experience, adjusting the idle speed did make a slight difference, but certainly hasn't solved it - just made it happen a lot less frequently (first time in two months yesterday).

I was wondering if it was caused by a loose cable somewhere that was either losing connection or shorting out?

Al.

[petevtwin650]

How can I go about checking the choke? It's completely off as far as I can tell. Also, how can I increase the tickover?

The choke lever controls a cable that goes into a splitter box. In the "off" position it takes the tension off the two choke cables that go to the carbs. These are actually closed by a spring on the the cable that is about as substantial as a retractable biro spring! So if there are any deposits/crud on the choke plungers they will more than likely stick. Wonder why no one has made a more substantial spring for them. Anyhoo, you need to get access to the carbs and see if ,with the choke off, there is too much freeplay in the seperate cables.

Front choke

http://i72.photobucket.com/albums/i184/petevtwin650/org%20tech/frontchoke.jpg

Rear choke

http://i72.photobucket.com/albums/i184/petevtwin650/org%20tech/rearchoke.jpg

Choke cable with the splitter box open to allow to pack with light grease.

http://i72.photobucket.com/albums/i184/petevtwin650/org%20tech/chokecablers.jpg

[shifter]

I would also check that that your battery connections are tight as poor connections can cause the bike to cut out. Check that your stand comes up tight and isn't flapping about and is clean around its electrical contacts. Also keep an eye out for any chaffed wires anywhere.
I would tend to agree it's probably carb related but these are not bad things to check just as routine maintenance.