Lost one cylinder, then the other

Hey guys.

Just got back from Corsica yesterday and on my way home I broke down twice! First thing that happened, I was on the M4 fast lane just going along normally and the bike just suddenly went down to one cylinder. I pulled over, managed to restart the bike, but it would only run on the back cylinder. There was no intermittent on or off, the front cylinder just stopped firing. It wasn't raining so it wasn't the front plug problem. I wiggled the HT lead and that didn't help (mechanically minded, me ). Luckily Philbut was nearby in Bath so managed to come and help me. We couldn't get the tank up because of a rounded off bolt so I just decided that because the engine was running still fine but just on 325cc I would limp home to Banbury. The red warning light was on and the words "FI" were illuminated (K3 SV650N incidently).

Several tens of miles later in Oxfordshire in the middle of nowhere just as everything was going well I heard a "pop" sort of noise, like I'd run over a twig I thought, and the remaining cylinder died. I coasted to a stop and had a look what was wrong. When I turn the key to turn the bike on, the lights go on and the display looks fine, but the buzzing of the fuel pump doesn't happen. After 2 seconds of the self test thing, the display looks totally normal but it just says "Check" in the corner. The fuel pump never buzzes, and the starter button does nothing, its totally dead. I had to get recovered back to my house so now I need some help quickly to find out what is wrong please!

So far what me and Phil think: For the first cyclinder, we thought it was probably a coil or the fuel injectors. But now its totally dead it feels like something blew up electrically. The lights and display and everything work fine still though so it must be with the fuel injector thing. This is where my mechanical knowledge disappears however! What should I check tonight, assuming I can get my tank off with the rubbish cheese bolts?

Yes I flicked the killswitch on and off and checked that, its not that

I wonder whether a coil went for you to loose the first cylinder, then running for that distance on one cylinder has blown something else. I don't really have a clue what this could be and I'm just speculating, so this isn't a BASAT post. Will be interested to learn what it was though.

[andrewsmith]

I'm thinking with it being FI its an injector failure or engine electrics have combusted themselves. Again not a BASAT post.
With the rounded bolt junior hacksaw or dremmel and a screw driver.

With ralph more curious than out.

[Paul the 6th]

(what the hell is a basat post?)

I had a similar problem with mine refusing to prime the injectors last week - rocked the shyt out of the bike while it was in gear, turned the ignition off and back on and it primed ok. Thinking it could be sidestand/clutch switch or strange kill switch issue..

Need to whip it all to bits ahead of 2 trackdays in 15 days time!

[yorkie_chris]

Originally Posted by Paul the 6th

what the hell is a basat post?

is the post sound advice.


sounds electrical. I would be looking at earths to the ignition system and other funny business. No fuel pump priming suggests it could be safety switch related too.

Thanks guys, I'll try to take a look at all that. Don't really know what I am doing but I have a copy of the manual so I'll see if there is anything obvious. Any more ideas, please keep them coming!

Dude (glad you got it home in the end) this sounds like a connector issue to me. Either that or some of the loom has worn through to create a short. Now the fuel pump is not priming either it seems there is a total failure in the ignition circuit. First job - check the ignition fuse. If that is blown, then chances are you either have a break in the loom somewhere that is shoring out, or a connector has completely come away which can cause an arc (had the same issue with my alternator to reg / rec connector block on the ZZR. Get the tank off and start inspecting the ignition loom. its not that big or hidden on the SV so shouldn't be too hard. If it all looks good, get yerself a multimeter or test light and check the continuity between all the pins. That will at least ruel out or confirm the loom.

Great advice Phill, thanks for offering to come up and fix it for me!

Ok ok, I'll try on my own first. I will get that bolt off first, then get the tank up and see what I can see. I am hoping for an obvious connection that is broken or a rubbed wire, cos I really don't know where or what all the ignition circuit is. Thanks for the help! (prepare to be phoned haha)

You know if I wasn't about to head off to big chill / Portugal I'd be round to help. Just bad timing mate, make sure you break down in winter next time - I never go anywhere then. rather bizarre that I happened to be coming down the M4 past you though wasn't it.

[Stu]

Originally Posted by philbut

rather bizarre that I happened to be coming down the M4 past you though wasn't it.

I blame Phil