View Full Version : major running problem. Suggestions needed
I took my curvey out for a 60 mile round trip the other day and for the whole of the outward journey it felt very flat, was unhappy ticking over and needed coaxing to re-start if it stalled.
Come the return journey, it needed full choke to start, even though I'd only been stopped for about ten minutes, and for the first couple of miles would only run on one-and-a-half cylinders. Once it stopped doing that it popped and banged through the exhaust every time I shut the throttle and when I got to a stretch of open dual carriageway I found it no longer had enough power to pull top gear. By the time I got home it wouldnt pull anything higher than third gear and was overheating so much I could smell it at 30mph, which was pretty much maximum speed by then.
I was convinced one of the chokes had jammed but neither had. Nor had either of the air screws unwound itself nor the diaphragms split.
More in hope than expectation, I replaced the spark plugs, put it back together again and was astonished when it started first prod of the button and appeared to run normally. It was only when it started to warm up that I discovered that all it will do now is run on full choke when stone cold. Back the choke off as it starts to warm up or apply even the tiniest hint of throttle and it instantly splutters and dies.
I've now run out of ideas.
HELP!!!
Might be worth having a look at your coil resistance and the electrical connections to the CDI.
At the minute, I can't think of anything else. Hopefully someone else with greater technical knowledge than I will be along shortly!!! :lol:
That was suggested by a bloke at work, but the evidence points so much in the direction of a carburation problem I'm not convinced (In any case, he rides a Kawasaki so is not worth taking seriously)
PS. How much humble pie will I have to eat if it does turn out to be an ignition problem?
PS. How much humble pie will I have to eat if it does turn out to be an ignition problem?
I'm after some Ohlins springs, so you could buy me some of them if you like? :lol:
>>and was overheating so much I could smell it at 30mph, which was pretty much maximum speed by then<<
What could you smell ? petrol - coolant ?
Did your overtemp (the red LED on the clocks) light come on ?
I would also suspect carouration in the first instance, but I'd also check your coolant levels (I used to have an MGF, so was quite used to coolant smells).
Check your oil etc.
Is the bike modified ?
It was the kind of smell you get when you've been caning it really hard - mostly hot metal. Oil and coolant levels checked seconds ago and found to be exactly where they ought to be.
One day I'll learn to answer peoples questions in one go, rather than in installments.
I dont think the temperate light works. Certainly I've never seen it on, even when I first turn the key and all the other idiot lights come to let you know they're working. Is it supposed to do that?
The bike is not quite standard, having had BMC filters throughout the two and a half years I've had the bike and a Quill T3 street pipe for the last year and a bit.
I should also add that this bike has a history of carburation problems. Just a few hundred miles ago, for instance, I had to chug it 60-odd miles back from London on one and a half cylinders. I was then convinced a choke had jammed but it turned out to be an air screw that had unwound itself a remarkably long way in an extremely short space of time. That is why they are the first things I checked.
Have you checked all the fuel lines to your carbs? Perhaps your bike is running too lean and that's why it only runs with the choke open fully seen as you're running a different filter?
A fuel blockage was another of the Kawasaki rider's suggestions and has been checked and found to be okay.
Still could be that your bike is running too lean though, given it'll run with the choke on. Might be worth having a look at the fuel/air mixture and giving it a bit of tweaking?
Mixture had three months of tweaking when the T3 was first fitted and, except for chokes jamming twice and aforementioned airscrew unscrewing itself, been fine for the last year. At this year's Manx Grand Prix I managed a qualifying lap time when two up on open roads! There could have been nothing whatsoever wrong with the carburation to have achieved that (Okay, so I wrecked a chain in the process and had to ride home with knicker-elastic transmission, but that's a different matter)
This is, I'm convinced, yet another example of my carbs taking it upon themselves to do something nasty rather than a long-term fault getting worse.
PS. Am I allowed ketchup with my humble pie if I'm wrong?
If you're coninced it's your carbs then it looks like you'll have to get them stripped down and give them a good old clean.
When were your spark plugs and leads last changed by the way?
Plugs were changed yesterday. I assumed HT leads were integral with the coils and didnt realise you could change one without the other. I'll try that one as soon as daylight returns.
I get the feeling that you are hinting I've so totally convinced myself this is a carburation problem I've closed my mind to other possible explanations. Am I right? Is this a side effect of consorting with Kawasaki owners?
I was just making suggestions buddy, don't fret! :lol:
PS you may well be right about the leads and coils though :oops: [/u]
Sid Squid
08-11-05, 06:38 PM
(In any case, he rides a Kawasaki so is not worth taking seriously)
As well as an SV1K I ride a Kawasaki but FWIW I think you need to empty the float bowls and ensure that the fuel tank isn't contaminated, probably with water, while you're fiddling with the carbs I'd ensure that the chokes are freely working, if they snag at all, and that could be just a mm or two they'' not seal and wierd running may well occur.
But I've got a Kawasaki, so what do I know?
Interesting!
The first 200 yards of my fatefull journey were to the petrol station for a fill up, so the contaminated petrol theory is an extremely distinct possibility. I'll put that one to the test as soon as I can find a container big enough to hold the three-quarters of a tank-full of potentially contaminated stuff I've still got aboard.
What condition were your old spark plugs ? Did they show any sign of overheating ?
I assume the radator fan was on all the time it was hot ?
Could the ignition timing be different ? - ie any devices fitted to give 'more power', or has the signal generator (for ignition timing) been disturbed ?
I'd still be looking for fuelling problems here - but condition of the old spark plugs should be a good indicator.
ps. The only time I got my overtemp light on is when I got a coolant change wrong - and it came on quickly but still ran fine.
Sir Trev
09-11-05, 12:46 PM
Can we assume that your carbs are in balance? I know from checking mine that the adjuster screw has no locknut and relies on the intergral spring to keep things still. My rough running curvey was MUCH better after I balanced mine and it would also take something else out of your conundrum list.
Carbs were last balanced about six or seven weeks ago and as the bike has spent half the intervening period sat idle, awaiting the delivery of a new chain and sprocket set, they should still be very close to spot on. In the past I've found them to be miles out of synch without them inducing running anything like this bad.
Old plugs were put in at the same time as the carbs were balanced and about the only thing I could say about them is that they looked like they'd done a lot more miles than they actually had when I took them out. If anything fancy has been done in the ignition department, it was done by the previous owner. I have to admit that, having discovered some of the other things he has done to it, he might well have but I dont think he did.
As the bike was running perfectly the day before this happened, Sid Squids suggestion that the petrol I put in at the start of my journey was contaminated sounds extremely plausible. I've already drained the suspect stuff out of the tank and float bowls and replenished the tank with hopefully better stuff from a different source. Unfortunately, before the new fuel had pumped through to the carbs from the tank the battery had flattened. The battery has now been on charge for an hour and a half, so I'm off to try again.
It's not looking good, I'm afraid.
I've now flattened the battery twice and had just one half-hearted cough from the engine for my trouble.
I'm starting to think that Jase22's polite not-quite hints that I was too obsessed with the carburation to consider the possibility of CDU failure were entirely justified. Has anyone had one give up the ghost on them to know what the symptoms are? The only electronic ignition failures I've ever experienced has been with cars, where they go from working normally to not working at all without an intervening period of rough running to mislead and confuse.
:lol: Does that humble pie taste nice!!!! :thumbsup:
There's something you might want to check before spending a fortune on new coils and suchlike though, have a look at the wiring loom that runs up the side of the subframe. Someone suggested in another post that the wires can sometimes short out on the subframe as the outer wears away.
Electrics can often do stupid things like this, my dad had a CDI problem on his FZR400 recently. His bike was running a bit crappy for a few days, then cleared up, then on his way to work it stalled and would only run at tickover even on full throttle. He stripped it down convinced like you that it was a carb issue as everything pointed in that direction. With a squirt of easy start it fired up and seemed to work fine....for about 5 seconds and then cut out again.
Sounds similar symptoms to yours and his was indeed a CDI fault. Perhaps you could proof this out by borrowing someone's, I'd offer but I'm a little far from Milton Keynes!!! :lol:
Add two cloves of garlic, ground coriander, cumin and cardamom, saute with some finely sliced shallots and a little balsamic vinegar, serve with dauphinaise potatoes and humble pie can be made to taste like . . . Humble pie!
When a component fails, why cant it plain and simply fail! Why does the damned thing have to linger, prompting is it? isnt it? is it something else entirely? speculation and thereby leading you up all kinds of false avenues?
I have a horrible idea that a new CDU will cost more than the bike is worth (Second hand CDU's dont appear to exist on E-bay) and as I'm 6'4" and the bike has always been physically too small for me I'm not sure if I should persevere or admit defeat and go on to something else that I might actually find comfortable. Any suggestions?
northwind
09-11-05, 07:32 PM
CDIs go by from time to time on Ebay at about £10... I keep on meaning to buy one just in case, but I never got round to it.
Spanner Man
09-11-05, 10:38 PM
Evening all.
Ditto Sids suggestion re crappy petrol. Also check the HT caps, the front one is particularly prone to getting dodgy.....The other thing worth considering is the dreaded carb icing which is starting to appear now....Get the heaters checked to see that they're working.....Re-locating the thermostat can help.....The stat is the black semicircular thingy with 2 yellow wires coming from it located near the coolant expansion tank. Without having to extend the wires, it's possible to poke it out from under the righthand side of the tank, therefore more in the airstream. Give it a try & see if it makes any difference.
Cheers.
SVGeorge
10-11-05, 12:30 AM
Hello Mike,
I have had a few ignition experiences with my SV and have actually ended up with 2 spare CDIs before discovering that the original was ok!
Some thoughts:
* Although you have changed plugs, etc, you don't seem to have checked if you get a spark or not. This might be best place to start to eliminate ignition or not. Either take out the rear plug and earth it while trying to start the engine (or just take the lead off and insert a new plug, then earth it) & check to see if you get a nice spark. If not, then it is likely a fault somewhere in the ignition cct. 2 people are best for this as it is a little difficult to do the clutch, starter button and hold the spark plug(with a insulated pliers, of course!) - or else tie the clutch in while testing.
* The best way to check the CDI is to remove it and find a fellow SV or perhaps a friendly bike shop might oblige, & try your CDI in another SV. Once you have it out of your bike(The rear body work needs removing to remove the CDI) , it is easy to try in another SV by just taking off the pillion seat, unplug from the CDI & plug your one in loosely. The reason I suggest like this is because if your CDI is blown, it won't damage another bike, & also there is minimum disruption to the other bike.
* Both ignition faults I had were broken wires - The 1st a worn solder joint where the Spyball alarm had been wired into the ignition cct. This was a right ******* to trace as all wiring looked ok when testing with a multi meter, which lead me to replace CDI & even the signal generator & it was only that eventually the soldered joint broke properly that I found it.
* The 2nd fault I have just fixed, but it was complete ignition cut out when sometimes turning corners, going over bumps or just putting the bike in gear! - the engine would cut, lights out, everything dead. That was the main igintion wire in the main loom where it runs from the headlight (Naked SV650) around the steering headstock & then in thro' the frame.
i.e. most electrical faults are wiring faults & not component faults.
George
Biker Biggles
10-11-05, 07:43 PM
I just saw a CDI on Ebay if you need one.Just search SV 650.BTW I agree with testing your one first as these fuel/ignition faults are tricky to pin down.
Lots of suggestions! Thank you! To deal with them in reverse order:
Biker Biggles. The only CDI unit I could find on E-bay is for a pointy. Are they compatable with curveys?
SV George. I do have sparks on front and rear cylinders but I wont know if they're happening when they should until shift patterns at work and other commitments allow me to swap CDI's with a donor (A further complication being that the potential donor is far from convinced we wants to be one. Hopefully your suggestion for preventing damage to his bike if my unit is blown will help persaude him) I dont think a broken wire or dodgy connector is likely to be the cause because, as you say yourself, they tend to cause intermittent, all-or-nothing faults whereas what I've experienced has been steady, if rapid deterioration.
Spanner Man. The problem is quite definitely not carb icing. The original problem occurred on that exceptionally mild day that set new records for November temperatures and I dont think we've had a cold day round here since.
I was convinced that Sid Squid's comments about dud petrol had the problem solved and I could hardly believe it when replacing the fuel didnt cure it. Since then all I've got out of it has been the odd half-hearted cough, but what I have noticed is that it always coughs when I prod the button for the first time in a session. That kind of thing hints at a carburation problem but I cant think of anything to do with the carbs I've not already done or checked.
A final thought. What does the "throttle position sensor"do, how does it do it and what would happen if it failed? Does anyone know?
skidmarx
11-11-05, 02:48 PM
my 2 pennys worth.......sounds like fuel'air problem for sure, Esp as it crops up when you've warmed up and you've sparks. It also sounds like whoever had he bike before you was very cack handed and probably pulled the thing apart for fun. Have you checked the throttle bodies are securely mounted and there is the correct gasket in place? When cold you were probably alright but as it got hot the expansion weakened the joint to the block or blew the gasket seal. This explains why it was ok at idle....sort of.. but died as soon as you touched the throttle, you maybe pulling in loads of air from a duff seal.....WHAT COLOUR WHERE THE PLUGS? White then too much air/too hot? Black too much fuel or dodgy electrics resulting in unburnt fuel...sorry if this is just repeating stuff..GOOD LUCK!
Plugs were pretty much the colour they ought to have been but looked as though they'd done rather more miles than they actually had, which I assume was a result of the battle they'd had coaxing me home.
SVGeorge
11-11-05, 06:13 PM
Hello Mike,
Have the symptoms changed? I thought you could start cold on full choke & then it would die or not take any throttle when warmed up, whereas later posts suggest it won't start at all now but gives a cough when you initially try the starter?
Also, I don't know the BMC filter set up, but it is always worth eliminating the foam piece under the tank. This has a history of coming loose and acting like a choke over the air intake. In some cases, it seems obvioius in that the foam is visibly hanging down, but in my case it was only loose right in the middle area of the foam & I only sussed it when I was trying to fix a fault where my bike ran fine at low throttle, but died when opening the throttle quickly. After doing a lot of the checks you have done, I just happened to notice a ring shape in the foam when I had the tank off & sitting upside down in good daylight. Even though the foam appeared stuck on ok, I could pinch and pull away the middle easy. What was hapening was the pull of air intake would pull the foam down as I opened the throttle. The ring shape was caused by the foam pressing down against the std air filter box. Probably a long shot, but easy to eliminate.
George
Ironic that you should mention the foam padding on the underside of the tank!
I've just got home after visiting my local Suzuki dealer to investigate the cost of a new CDU (£450, which - while still a lot of money - is better than the £7-800 I'd feared. Apparently that's the kind of money a CDU for a Honda would cost)
While I was at the parts counter one of the mechanics came up to get some bits and, desperate for professional advice, I dragged him into the conversation I was having with the parts man. Apparently there isnt a reliable test for SV CDU's ("Even ones that are working perfectly fall outside test parameters") and, in any case, he's never met a defective CDU on an SV. He asked me why I thought mine might be dud and when I told him he gave me an odd look.
"That's a carburation problem." He stated emphatically.
"But I've stripped and checked my carbs." I protested.
"Strip them and check them again." He advised, and added exactly the same comments about the foam padding on the underside of the tank that you've just made.
By the time I got home it was dark and as my shed is unlit I had to use torchlight and feel to check my foam. I think its okay, but I'll obviously check again when its light tomorrow.
Meanwhile, I've been thinking about his absolute conviction that the problem lies with my carbs and wondering what kind of problem could affect both carbs at the same time and worsen at the same rate. Could the tank-full of petrol I bought at the start of my bikes last journey have been so far past its "Best Before" date that it gummed up the jets then spent the last week hardening? That might explain why my engine has gone from feeling flat, to running rough, to only running on full choke to not running at all.
northwind
11-11-05, 07:40 PM
http://cgi.ebay.co.uk/suzuki-sv-650-s1999-coils-ignition-boxes_W0QQitemZ8013738159QQcategoryZ10534QQrdZ1QQc mdZViewItem
Thanks, Northwind.
Bid placed.
jumper7147
12-11-05, 05:56 AM
I've an '02 with the exact same symptoms, including better (but brief) running after plug maintenance. Kicker is, it's bone stock, never been apart since new. Had great fun in the twisties of Northern CA, but use it for traffic avoidance in LA. Let it sit for four months, now it barely runs. Carb varnishing? Is a good carb cleaning something an amateur should try? Looking forward to any help.
wheelnut
12-11-05, 10:48 AM
In my experience it will be electrical, make sure you have good dry tight connections on the lt side of the coils, they are a pig to get to,
Your experience echo mine with the curvy, poor running, missing, excessive heat, lack of power etc
Carbs do not just go off, or lose settings, electrics can cause the same problems and can be intermittant
Removing and stripping the carbs is fiddly but not difficult.
Remove the fuel tank before you start. You'll find it gets in the way if you try to work with it propped up.
As for the carbs themselves, the hardest part of the job is undoing the hose clips that secure the air filter box to the carbs and, particularly, the carbs to the inlet stubs. You'll need a fairly long screwdriver and good illumination. For the rest of the job, it's simply a case of being methodical and following the manual.
One thing: If you are using a Clymer manual, be wary of the settings it recommends for the air/pilot screws. The settings Clymer give for the UK spec models are wrong so the US settings might well be, too. Count how many turns yours are set to when removing them for cleaning and reset to the same number of turns when reassembling.
northwind
12-11-05, 02:19 PM
Also, teh choke screws and the ones that hold the bottom of the float chamber on often give people problems- they're very soft, and since they never get disturbed for years on end they can be very bad tempered. If you're taking the carbs off for the the first time it's pobably easier to remove the choke cables at the control end and then remove them from the carbs once they're out. Or just don't bother, but I think it's something worth fixing. I binned the standard screws and fitted allen-headed replacements.
SVGeorge
23-11-05, 09:58 AM
Hello Mike,
Did you get running yet? Just wondering what the latest is?
George
Chatterbox
23-11-05, 08:01 PM
Just a thought, have you checked for air leaks on inlet ports?
Its easy to check, just spray wd40 or just about anything where carbs fit on to engine whilst ticking over.
If it starts racing or dies it would show the way to go.
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