SV650SK2 Engine Misfiring / Cutting Out - Saga.

I've spend a while searching and going through threads but can't seem to find this exact issue.

Bear with me as I'm mechanically inept.

I'll put as much info as possible, as this issue has stumped my local mechanic so far.

Bought my SV650SK2 a couple of years ago, second hand, about 12k miles on the clock (now up to about 24k), from what I remember. Had it restricted to 33bhp (?) in compliance with my licence. It came pre-fitted with a Scorpion can with baffle, I used the bike both with and without the baffle in.

Late last year I went wide on a corner and slid the rear wheel out in some mud, managed to slow down a bit first but dented up the can.

Had it running all fine through the winter and about four months ago bought a Viper can to replace the dented one. The bike was ok for a couple of weeks but started misfiring - a sort of stuttering - when running at about 70-80 in 6th (dual carriageway to and from work). Also started having problems starting it up, starter motor wouldn't go. Turn off, sit for a couple minutes, and try again - fires up ok.

Local mechanic had a look at the wiring/spark plugs/etc, couldn't find a fault. Suggested the start failure was the side-stand cut-off, so disconnected that . Seemed to have sorted that. Suggested the misfiring was due to the new can, and the carbs jets probably needed adjusting, so he bought a kit and did that.

The misfiring didn't go away and in fact got worse (but I don't think it's worsened by the re-jetting), now the engine would cut out then kick back in several times then maybe be ok for the rest of the journey or have the problem again in a few miles. This got worse to the point where it would misfire several times as before but then cut out and not kick back in. So I'd pull onto the hard shoulder and try to start it. Fired up ok in neutral, side stand up, kill switch in correct position, clutch in, and change to first gear. Stall. Try again. Stall. Wait 2-3 minutes, and try again, and this time it wouldn't stall, and would run ok for a while, maybe even to the end of the journey.

After this the mechanic disconnected the immobiliser and the clutch switch (where you hold it in before using the ignition). The problem persisted and after some reading around I suggested changing the CDI. I sourced one from a bike breaker on ebay (supposedly fully functional), swapped the existing one out for that. Still same problems. Was now finding that it seemed to be ok if I'd left the bike for a couple of days, it would run alright for a couple of days - only started noticing this as obviously it took several days to get the new CDI.

After more research I suggested we could try the coils, so he arranged to get the generator coil sent to a Suzuki specialist to be re-wound, and borrowed some HT ignition coils from a friend with a bike temporarily in pieces (stripped down for other reasons). In the meantime I realised I'd had my bike licence for two years and could get the restriction removed, so got him to do that while he was there. Still no resolution to the problem.

The current status is that he's tried replacing the fuel pump as he's now read somewhere that might be the problem source. I've yet to pick up my bike to give it a ride, and suspect that - as before - if the problem is still there, it won't show up for a few days riding. Which is why I'm reluctant to get back on it with the possibility of more stalls with high-speed traffic around. The worst occasion was when overtaking a slow truck up a hill, the engine died just as I came along side, a car came up behind me, so I had no choice but to make for the middle hard shoulder area.

Anyway, any suggestions are very much welcome!

[jambo]

An intermittent fault is extremely frustrating. Well done on remaining up-beat. I would imagine it is electrical rather than fuel, but there's a check for this:

When it's not working, quickly pop the tank up, use a spare spark plug on the rear spark plug cap and earth the plug on an engine bolt. use the starter motor and check for a spark. You may well find there is no spark when there's a problem but it starts firing again after a minute or 2 when it's cooled back down again.

Benji on this forum had a similar issue and it turned out that the wiring loom itself was at fault. There are several places it can rub through:
* The behind the bolts that hold the rider's seat on
* Around the headstock
* Around the rear sub-frame

Check in each of these places to make sure that the wiring hasn't rubbed through the insulation & started to short out. Other than that it may be a bit of fractured wiring in the loom. Benji's fault was only resolved when the wiring loom was replaced with one from a breakers, but this takes time and money so it's worth doing some basic checks first!


Jambo

Thanks for the quick response jambo, I'll check through those ASAP.

Just picked up my bike from the mechanic so shall see how it goes.

Thinking about it more, I'm fairly convinced it's not specifically electrical, as whenever the engine has cut out fully I've then put it in neutral, started it up ok, then kicked it into first gear and that's when it stalls (until it's had a few minutes rest).

I'm thinking that if it was faulty wiring, I'd need to - I dunno - shake the bike around a bit before I could start it up again in neutral.

The chap clarified that he hadn't previously disconnected the clutch safety thinger-ma-jig, but has now done so. We'll see how I get on, I suppose.

[jambo]

I would suggest if selecting neutral makes any difference at all, it's going to be leccy.

The side stand cut out and clutch switches are both potential weak points that can cause the symptoms you describe. check both are effectively bypassed and do be careful not to start the bike with it in gear or something and damage it while they are!


Jambo

[NedSVS]

I've had a smilar starting problem with 2001 SV650S but not much trouble with the misfire. I now know that my problem is down to the dodgey headlight sub wiring loom I fitted when converting from a Euro to a UK headlight. This little sub loom connects all the handlebar switches as well as the lights, so affects the engine kill, starter and clutch safety switch. They are quite prone to corrosion, especially on bikes used all year round and the one I bought off Ebay was quite poor. Despite spending several hours cleaning it up it has caused me intermittent problems (anyone got a nice clean corrosion free one to sell?). If you reach inside the fairing on either side you can get hold of the main loom (just infront of where the winkers stick through). Give it a rattle when the bike is ticking over to see if you can induce the problems. When my bike wouldn't turn over to start I'd just give this a rattle and away it would go, but also sometimes once started I could kill it by fiddling with this!

There's a couple of things you can look at here. Try shorting the kill switch on the right hand bar, had a 600 Honda that was a bitch to get to go till I re-wired it. Has your spanner man put new plugs in it? If not then there's another one to look at, if one of them's tracking then this can happen. New on me till yesteray on another board, this was causing the same fault on an XJR. It has to be a leccy' fault as if it was a fuelling fault then it would die off rather than cutting out. The chances of it being a CDI unit are so slim it's not funny unless you work at Chernobyl or been at any Atomic bomb tests lately, they're pretty much undamageable. Make sure your coil leads, LT side are in good order as I found out the other day, thanks guys again on here for the pointers, if you re-jetted then the front coil is the most likely culprit.. As Ned said, make sure the wiring loom behind the headlight is good as well, it flexes a lot here and broken wires can take a lifetime to find.

Thanks for the feedback guys, more to look into. Been running it into work and back for the last couple of days with no problem so far, but I'll look at these things.

I have had the same fault for a while now, got so bad just stood bike up in the garage for 3 months but with better weather coming got the itch to get back on the old girl, I did the same thing with trying to bypass the side stand switch to no avail but all symptons pointed to this as the problem. After reading your post I stripped back the wiring loom tape from below the fuse box to discover the mess of connections that suzuki have hidden under the tape . There I found the green wire solded to the black wire, all I did was scotch lock the black and white wire to the side stand switch, to the black wire and hey presto fixed fault fixed , thank god no more cutting out as riding. Must of been poor or dry solder which over time has failed . Hope this helps any other poor soul's pulling there hair out with this problem.