SV cutting out

[munkygunn182]

Hi all,

Just passed my test today and went to take the bike a ride today. It fired up on the button, but cut out at the end of the road, started up again, backfired and died, started again, rode normally. At the end of the ride, had it switched off in the drive, and the same happened again, but without the backfire.

The bike in question is an SV650S K6 on a 2006 plate. Completely standard. Only change was today I changed the ECU to a 33bhp one. After the ride I swapped back to the standard ECU and the bike fired up and idled quite happily. I attempted to prove a faulty 33bhp ECU by swapping the restricted one back in, but the bike fired up and idle's happily.

Safe to say im rather confused! Should note, i haven't had a chance to get it back out a ride to prove or disprove the ECU swap since i got back.

Any help would be great!

[speedplay]

has the bike been stood for a while with old fuel in it?

[munkygunn182]

It's been stood about a week underneath a polythene sheet

[speedplay]

was wondering if it was just dodgy fuel in it.

Thats not Ralphs old pointy is it?

[munkygunn182]

It's just the fuel it was delivered with, i couldn't vouch for its age or origin

[munkygunn182]

Yeah its ralphs old pointy, how did you guess?

[speedplay]

cause it cuts out....;)








Just kidding!
Theres not many red pointys about and know hes just sold one.
Give him a shout and ask him how long the fuel has been in there.

[shifter]

Check the basics first, Battery, fuel filters and breathers. Also if it's been under a tarp and outside in this weather it's quite possible that the damp has got at the electrics.

[munkygunn182]

The battery was pretty weak to begin with, seemed strong enough after the run though, don't know if that would affect?

[shifter]

It would. Petrol engines usualy rely on the battery to provide the low-tension juice to the ignition system, week battery means week spark.
Often when the reg/rec has failed (isn't charging the battery) the first sign is that the bike will start and run for a bit, then just dies. You can often restart as the battery recovers a bit, but then the same happens.
Might not be the answer in your case but worth eliminating from your equiries.

[munkygunn182]

So it'd be worth checking the charging voltage being provided?

[shifter]

You can quite easily start panicing and thinking major problems, only to find it's something stupid. For the sake of 5 mins checking it it's worth a look. Also batteries are prone to fail when the weather turns cold.

[munkygunn182]

yep, well i'll get that checked asap and see how we get on. I know its due a service, so it'll be getting new oil, plugs and filters as soon as i've got cash, so all going well, that'll sort it out. Only thing i can't do anything about is the damp

[shifter]

Get a can of WD-40 and F**k it alover the electrics, including the plug caps. My useless piece of info for the day is that the WD in WD-40 stands for water displacer.
It might smoke a bit when it gets hot but wont do any harm.

[-Ralph-]

You have PM.

Fuel was put in during my bike safe ride on 3rd October, so it's 2 1/2 months old. Lots of people garage their bikes for 6 months over winter without using a fuel stabiliser, and have no problems. I really doubt it's that.

Your ECU is the most likely because that's the last thing you changed before the problem started occurring.

The second most likely is spark plugs, they are due to be changed now (8000 miles old).

Damp or cold is quite likely, that bike has never been kept outside, so I don't know how it will behave with that.

The battery or reg/reg was last checked last year in London. I think I parked in some ar$eholes normal space, and when I came out to leave I found the heated grips were on and the battery was flat. It definitely wasn't me that left the grips on, I checked it about 3 times before leaving the bike. The AA put a multimeter across it and it was fine then. Search on here will tell you what voltage you should be getting at what revs.

[shifter]

Sound like it's back to the damp thing or the ecu then. Condensation can do funny things with the electrics, the wd bath might be a good start. From the fact your getting loud bangs when it cuts out does sound more like an ignition issue rather than fuel. Perhaps a set of new plugs might be a good idea to start with.

[munkygunn182]

So when giving it a bath in WD-40, where do I want to concentrate on?

[boot]

Would try riding it again before doing anything else. As you say, it fired up fine after swapping the 33bhp ecu back in, so you may not even have a problem.

[munkygunn182]

Yup will do, when Ralph sold me it, he made it clear that it was due a service, so that's getting done regardless. I'll try and get it out for a few miles tonight, weather permitting.

[Specialone]

When running, you should get about 14. something volts from the battery, 11.5v- 12v when switched off.
But even on a bad battery you can still get 11-12 volts but no serious ampege to run a bike with.
As Ralph said, its more than likely the ecu restrictor, cos its always ran well before you changed that.

2 months old fuel is nothing, fuel is designed to last longer than that.
Id feel happy using 6 months old fuel but not much longer than that as it starts to go sticky and gunky.
That said i once run a lambretta in the 80's that had been sitting for well over a year that ran fine, but it was 2 stroke mix tb fair.

[munkygunn182]

Yep absolutely agree, everything appears to point to the ecu or dampness. Is there a way of having an ecu tested?

[munkygunn182]

Well, i got home from uni today, and the SV fired up straight away, so i let it get up to running temperature, and it all seemed okay, running smooth, idle dropped to ~1200rpm which from what i can see in the manual, appears to be correct. So i'll try and get it out a wee run later on and report back!

[-Ralph-]

so i let it get up to running temperature

It may just have been a bit damp from sitting stagnant in my garage, then outside yours for a week with condensation building up on all the metal surfaces (including inside the engine), with the engine never getting hot enough to steam off and dry up any moisture. Can you see steam coming out of the exhaust when it starts, then rising off the bike shorty afterwards. as it warms up? Take it for a damn good blast in dry weather, and get the bike properly warmed up and the battery properly charged (it has never needed a battery charger, just a good ride, but if kept outside in the cold you might not get such good service out of the battery). Do the service then give both spark plug chambers, HT leads and coils a damn good blast in WD40.

[Bibio]

i thought you passed your test?

it'll be the ecu, maybe not plugged in enough?

[munkygunn182]

The exhaust was certainly blowing a steam like cloud for the full 45 minutes it was running. When I shut it off, the temp gauge was reading 100 degrees. Did it sit a while in your garage?

[shifter]

Wd wise I go for almost everything electrical, all the multi-plaugs, round the battery relays and fuses etc. Just wipe the excess off with a cloth. If nothing else it cleans things well and I like to think it helps to kick any moisture out.
I used to off-road an old Land Rover that used fluff out at the first sign of water and wouldn't restart, i used to squirt a load of wd around the distributer, coils and ht-leads and it would fire on the button so I think it helps.

[munkygunn182]

i thought you passed your test?

it'll be the ecu, maybe not plugged in enough?

Hey Bibio, yep the test is passed. Last night i swapped the ECU's round, and checked they were in tight, so hopefully i'll get it out in the next hour or so to see how its doing. Don't fancy taking it too far seeing as its due a service, dark, and needs new tyres :)

[-Ralph-]

Did it sit a while in your garage?

Yes, it has been sat for a while. Pretty much since I put it on sale.

[munkygunn182]

Ach well, i'd suspect damp then, i'll make a damn good effort at drying it out! We'll see how i get on later tonight. Found out the hard way yesterday that its damn easy to stall!

[munkygunn182]

Post run report then:

1. Started up and instantly cut out
2. Started up and kept running, cut out when put in gear (damp in sidestand switch?)
3. Started up and ran flawlessly.

Diagnosis?

[speedplay]

Diagnosis?


Rider being over worried?!




;)

[munkygunn182]

Haha I'm brand new to the thing, if that's how its meant to behave and that's how it behaves on the home leg then I shall hold my wheesht! :p

[speedplay]

Haha I'm brand new to the thing, if that's how its meant to behave and that's how it behaves on the home leg then I shall hold my wheesht! :p



Ralphs not a bad bloke for a scot, I doubt very much that he would sell you a bike with problems and not tell you about it first.

As Ralph has said, its been sat for a little while and probably just needs a damn good run.

[husky03]

give it a good run-even motorway (down to carlise and back)-that'll dry it out-and buy a shed-100 quid b and q and stick a greenhouse tube heater in it(2p an hour to run)-that'll stop the dampness.

[munkygunn182]

Well I'll take it a good run as soon as its been serviced, but for now I'll shut up!

Thanks to all for the advice and fingers crossed it behaves :)
Ralphs not a bad bloke for a scot, I doubt very much that he would sell you a bike with problems and not tell you about it first.

As Ralph has said, its been sat for a little while and probably just needs a damn good run.

[-Ralph-]

Speedplay has knocked the nail on the head mate.

I wouldn't worry about it dying if you have only just started it. All bikes do that from time to time, especially twins and singles where there is a bigger blip if one cylinder fails to fire for any reason. I would normally start it, give it 3000 revs, then ease of the throttle and let it settle onto the automatic choke at about 2000 revs, after 20 seconds or so it'll drop back down to 1200.

Don't forget the bike will be 5 years old in May and has 23,000 miles on it, it's not brand new!

If it cuts out when you put it in gear that might be a damp sidestand switch, but the only time it did that to me was when I had actually left the sidestand down. Did you check that? ;-) Still if it does it once I wouldn't worry about it.

AND BEFORE YOU WORRY ABOUT ANYTHING ELSE, GET THE DAMN THING SERVICED! A weak spark plug won't be helping matters.

[speedplay]

Speedplay has knocked the nail on the head mate.





Your not a bad bloke for a scot?! :rolleyes:

[dyzio]

idle dropped to ~1200rpm

I can't remember what rpm the SV was idling at, but you could try raising this a bit.

Dunno why but seems a bit low, or is it just me?

[-Ralph-]

Is it really a backfire (loud bang from the exhaust), or is it a keerrr dunk clonk and sudden stop from the engine. If the latter it is one cylinder giving up, which could easily be a tired spark plug. If the side stand switch it will come to a nice smooth brrrummmf! and stop just like you hitting the kill switch.

[-Ralph-]

I can't remember what rpm the SV was idling at, but you could try raising this a bit.

Dunno why but seems a bit low, or is it just me?

Its just you.

[munkygunn182]

Nah it's deffo a backfire. Just done it there, started, died, backfired... So I've decided I'll stay here a wee bit longer :p


Is it really a backfire (loud bang from the exhaust), or is it a keerrr dunk clonk and sudden stop from the engine. If the latter it is one cylinder giving up, which could easily be a tired spark plug. If the side stand switch it will come to a nice smooth brrrummmf! and stop just like you hitting the kill switch.

[-Ralph-]

It's got to be your ECU, it's never done that before.

[munkygunn182]

Yep, I'll be getting another ecu asap. What to do with this one though!?

[-Ralph-]

Yep, I'll be getting another ecu asap. What to do with this one though!?

Did you keep the receipt?

[speedplay]

Just a thought, bu is it the right ECU for your bike?

I know there were a few different ones.

[munkygunn182]

It was bought from one of the guys from the org who said it'd fit a k3 right through to a k6. I personally don't have a clue about them, so advice is more than welcome

[munkygunn182]

Well, I'd like to report that both the ecu and bike are fine, it was the muppet sitting on top that was causing problems!

[Specialone]

Well, I'd like to report that both the ecu and bike are fine, it was the muppet sitting on top that was causing problems!

Well dont feel bad, weve all done stupid stuff, but its the cheapest to sort out :)

[shifter]

What was it then?

[speedplay]

What was it then?

+1

own up then...

[shifter]

I can't think, if it was carbs I'd think he left the choke on or something......... nope give up?

[speedplay]

pointy....
no carbs...







disc lock?!


lmao

[-Ralph-]

You thought the killswitch was a nitrous button? ;-)

[shifter]

That's why I started my post "If it was carbs", I read in the first post it was FI

[munkygunn182]

Time to own up... As I pressed the start button, I also twisted the throttle, thus playing games with the fuel injection system. So the bike would flood, and on the next attempt backfire.... Silly munky!

[Bibio]

silly monkey. but from what i know it shouldn't matter if the throttle is partially open when you fire it up, but i could be wrong.

[shifter]

Ooops, easy mistake to make though. If you have the throttle open when it starts the ecu thinks that's the closed throttle positian, so when you then close the throttle you have too much fuel and it floods.

[Teejayexc]

Hi all,

Just passed my test today and went to take the bike a ride today. It fired up on the button, but cut out at the end of the road, started up again, backfired and died, started again, rode normally. At the end of the ride, had it switched off in the drive, and the same happened again, but without the backfire.


Safe to say im rather confused!


Now I'm confused, opening the throttle on starting wouldn't cause the bike to cut out at the end of the road ?

[munkygunn182]

Now I'm confused, opening the throttle on starting wouldn't cause the bike to cut out at the end of the road ?

I'm gonna put that down to lack of use. I'm a happy pup now!

[-Ralph-]

Ooops, easy mistake to make though. If you have the throttle open when it starts the ecu thinks that's the closed throttle positian, so when you then close the throttle you have too much fuel and it floods.

Hence the backfire, too much fuel. Interesting, I never knew the ECU did that. I have always opened the throttle when starting it and given it a few revs to get it running happy before asking it to idle on it's own, but only after the engine has fired, then I catch the first few fires and give it more fuel to get it spinning smooth. I think being FI the SV probably never needed it, but it's a habit from starting older carb & choke bikes.

[andrewsmith]

silly monkey. but from what i know it shouldn't matter if the throttle is partially open when you fire it up, but i could be wrong.

My understanding and dealing with FI the throttle has to be closed or the as said flooding can occur.

And i've done it with a FI YBR125

[munkygunn182]

A lesson to all then :p

[shifter]

In simple terms all Fi is, is a computer driven fuel pump, the computer (ecu) gets all its information from the various sensors and works out how much fuel to squirt in and when. As with carbs you manualy control the air with a butterfly, and the ecu uses a sensor (throttle position sensor) to work out how much air you are letting in, it then works out the fuel accordingly.
If you have the throttle open when you start the bike (switch on the computer) then it thinks the throttle is at zero when in fact it might be at say 25%, so then when you shut the throttle the engine has a lot less air than it thinks it does and will squirt in too much fuel.

[munkygunn182]

In simple terms all Fi is, is a computer driven fuel pump, the computer (ecu) gets all its information from the various sensors and works out how much fuel to squirt in and when. As with carbs you manualy control the air with a butterfly, and the ecu uses a sensor (throttle position sensor) to work out how much air you are letting in, it then works out the fuel accordingly.
If you have the throttle open when you start the bike (switch on the computer) then it thinks the throttle is at zero when in fact it might be at say 25%, so then when you shut the throttle the engine has a lot less air than it thinks it does and will squirt in too much fuel.

:winner: