Dead bike, Won't start - Help with draining carbs tank etc
 

Hi All,

Got big issues with my SV at the moment.

Went to start it today and it fired but sounded rough. When I tried to use the throttle it just died. After that it wouldn't do anything. It has been raining cats and dogs here - but that's never caused me a problem in the past, even when riding through it - and this time it's just been sitting there.

I think that fuel is getting through as when you open the throttle / choke it just turns over, when they close them it fires a bit - but only whilst the starter motor is going.

I was going to see if there was any water under the spark plug but can't see a way of getting what I assume is the plug cover off... DO I have to remove the radiator?

Anyone got any idea what the issue is here?

TIA

Stu

It may be water getting in your fuel tank.
I know "ping" had this problem and found out water was leaking through the fuel cap.

Does this mean I need to drain the carbs / tank to get rid of any water before it's likely to run again? Do you know if there is a way to find out if it's water?

TIA

Stu

Try emptying your tank onto a hard surface then put a match to whatever comes out. If it burns then its fuel. If it doesn't then its water! :takeabow:


Seriously though, it could be water in the fuel, but you would have to drain the tank and carbs and refill with clean petrol. Its the only way to tell unless you can take the fuel pipe off and decant some into a clear container. The water will be nearer the bottom. :(

It may also be an ignition problem such as the cdi unit, plug leads or plug caps. Failing all this it may be the cam chain has snapped (????????) which may or may not give intermittent compression resulting in what you are getting. Probably not this but then who knows :!: :?:

My advice would be to start simple, then panic :?

Re: Dead bike, Won't start
 

No you dont have to remove the radiator but you do have to dissconect it from its bottom mount, then it should swing free just enought to get to the spark plug. Put a block of wood in to hold it out of your way.

Thanks all. I'll give the sprak plug a try this evening - and see if there is any obvious water inside the filler cap.

If it aint working tonight I guess it'll have to wait until the weekend...

Stu

OK checked the plugs and they are absolutely bone dry. Going to fetch them our of the engine and leave overnight anyway just to make sure - also make sure I've not flooded the engine :)

At the same time I'm going to grain the carbs / tank. But I have absolutedly no idea how to do this. Any pointers? It's an '00 bike BTW.

Stu

This is quite possibly Mav's problem, but it isn't caused by the fuel cap leaking, what's happening is the filler well drain hole/pipe/hose is blocked.
If you lift the fuel cap and look into the well around the filler hole you'll see a small hole, (~3-4mm dia), toward the left. If it's blocked, rainwater sits in the recess on the top of the tank, when you open the cap to fill up it drops into the tank.
It's not unusual to find a significant amount of water in the fuel, but another problem is that if blocked, the metal pipe that leads from the hole to the underside of the tank can rust through from water sitting in it, if it does the tank is scrap as the pipe is inside the tank and not practical to repair. Most commonly the problem is the rubber hose that leads from the stub on the bottom of the tank, right at the rear by the hinge, is kinked. Carefully arrange the hose so that it's not kinked when you drop the tank.
But it's not unusual to find the pipe full of crud too, blow it out with an airline or foot pump, every so often check it's clear and squirt WD40 or a dab of light oil down it every so often to ensure it doesn't go rusty.

If you're going to do this you'll be dealing with fuel, so bloody well be careful OK.

And don't get fuel all over the floor, even if you don't barbecue the garage petrol is a bit slippy and you'll easily end up your backside, so be more careful.

To drain the carbs, lift the tank and take the airbox off, the drain screws are 5mm headed Allen bolts roughly pointing at each other between the carbs as they are mounted almost base to base, open them a few turns and let them drain. Good practice says that you should allow them to drain into a receptacle and then carefully dispose of the fuel, however if you can get anything in there to drain it into you're doing better than me. When whatever was in there isn't anymore, lightly tighten the drain screws, careful with this the carb bodies are made of a light zinc alloy and are very soft, it'd be only too easy to make a nasty mistake here so go easy, they just need nipping into place.

Draining the tank: Take it off and turn it upside down with the cap open, (preferably removed), shake it about to get as much out as possible, then remove the fuel tap to get the rest out, get a half pint of new, clean fuel and swill that around the tank, to make sure there's no water or other contaminants in there, reassemble it all making sure that any disturbed gaskets or seals are in good condition, preferably replace them.

Thanks Sid - after looking the carbs last night you've made me a happy man. I wasexpecting to see the float chambers at the side of the carbs, easy to get at type of thing. Niaeve I know. When I saw the set up I was expecting to have to remove and dismantle the carbs to drain. I'll look again the evening and give it a go before I put the sparks back in (checked to see if they were wet).

Do I just undo the feul tap under the tank with the two bolts? Or do I take the feul line off and leave the tap in place? (Sorry new to dismatling bikes - the Spitfire is much easier to work on :) )

Looking the feul cap it look slike water has got in this way. There is rust around where the cap seals, and a line of rust going into the tank. This is a new thing so I guess it's a hunt for a new rubber seal... I'll blast some WD down the drain tube to make sure it can come out the other side.

I'll check the

OK...

Drained the bike last night. - couldn't see any water in the petrol...

Refitted the plugs after letting then dry again and tried again. Still nothing.

Took the plugs back out again to check that they were both wet - and found the back one to be perfectly dry, the front still wet so I am assuming that I have ignition issues on the front cylinder. Looking into the carbs when turning the engine over it looks like there is petrol going into both cylinders - you can see the droplets in the venturi of the carbs.

Does anyone know How I can tell if I am getting a spark to a cylinder without sparking the plug against the engine and blowing up the ignition module? (Things are soo much simpler with points ignition :) )

Other than that does anyone know what is the most likely component to break on an SV that would cause no sprak to the front cylinder?

Thanks in advance
Stu