only starts with starter fluid

[Tiggie]

cheers, will keep it in mind, though anything lower than 100 and I'm going to go hide under my duvet for the rest of the day

[eastanglianbiker]

once you have refitted the carbs it might be worth replaceing the spark plugs for good measure just to make sure and means you can rule them out as well that way

[megawatt]

To get max compression for a test, put a few drops of light oil in bores, turn engine over slowly and then test it.

[Fozzie]

I'd worry if the compression came back low... I really didnt think these bikes broke easily in that way!

Just out of curiosity, it starts with the fluid so if compression was low I would imagine it would struggle even with that.

Sounds daft but have you got an inline fuel filter on the line? Or has that been asked/checked?

Just wonder if there is a restriction of fuel getting to it. Use a water bottle, flipped upside down, filled with petrol and use a new piece of fuel line just to eliminate the obvious.

[megawatt]

Going back to Tiggie's first posts;

"will start no problem if I spray starter fluid into air intake, then engine dies once fluid has burned up. I have stripped and cleaned carbs more than once I can open float bowl drain and put petcock to prime and watch petrol pour out so I know carb is getting fuel.

Battery is fully charged and I'm getting a spark at both cylinders."

This sugests that there is compression there and that the engine is only burning the Easy Start and not fuel. The plugs are dry, so fuel is not getting from the carb float bowls in to the engine.

I reckon there is a blockage in the pilot jet or main jet circuit.

Tiggie, how recently did you put fresh fuel in the tank or go on reserve? Worth draining the float bowl into a clear glass and seeing if there's any crud or water in there! Also try starting it with the fuel filler cap undone as a partial vacuum in there will restrict fuel flow. As said, low compression is unlikely, but needs eliminating from the equation.

The only other thing that would prevent starting is timing , either ignition or valve timing, but that is unlikely to go out overnight!!! Good luck and keep us posted

[Fozzie]

I've heard someone say some little Suzukis are terrible for letting water into the fuel tanks?

Hopefully if it were the case its just wrecked the fuel. If too much it will not compress and goodbye piston rings at the very least

[Chrissb6]

Poor lad put some hrs and head scratching into chasing this fault. Whats the bet that if the bike ran the day before we all looking at something stupidly simple Broken side stand switch, coil breaking down or in this case it may just be the fuel system. Just have to say, all my bikes with carbs have stood for months with the same old fuel in them and all fire up with no bother. To loose compression unless something has let go - gone bang, thats normally a progressive fault and not a instant fault.

[Tiggie]

ok then, i'm pretty much going with it been carb related now, so off to strip it to bits (again) reason I've come to this conclusion is i filled a spray bottle up with petrol and used it on the air intake, engine will run perfectly until I stop spraying then will idle and die.

I swear the jets are all perfectly clear and the rest of the carb seems ok, it gets fuel into the bowl, any ideas on things to try?

I can buy a new carb for £35 of ebay which i'm pretty tempted to do as a new set of jets was around £20

[Chrissb6]

Hi, as you rightly say if it runs with no issues with an alternative supply of fuel your in the ball park. That x's off compression and ignition side of things. Blocked tap, fuel line, sticking float or blocked jets. You might want to take the carb to the garage and get a second apinion before you go buying.

[Tankbag]

Sounds daft but the linkage to open and close the butterfly is ok ? just a thought, I really don't fully understand carbs, its all Greek to me

[Stu]

have you got some carb cleaner? to give it a good clean with?

[Tiggie]

I do have carb cleaner and have been using it a lot

I can blow air through each of the jets, see light through them etc which is why its getting so confusing

will just mention again that fuel IS getting into the bowl and the fuel is fresh and good.

It must be the carb but as yet I dont know why!!!

[Stu]

It sounds to me like the fuel isnt been drawn from the float bowl up to the jet

[Decor58]

Just skimmed through this thread and I would be checking your float and butterfly mechanisms.

Very odd how it has stopped so suddenly...

[Tiggie]

It sounds to me like the fuel isnt been drawn from the float bowl up to the jet

 

I think that is exactly what is happening. forgive the idiocy but is that due to a loss of vacuum somewhere?

[Stu]

when you say you can see through the jet is this when removed? can you see through the tube it screws on to

this is where the fuel is drawn though by the air causing a vacuum as it rushes through the inlet...is it blocked on the inlet side of the carb

[Stu]

this may help with the principle of how a carb works

carbs are a bit backwards and the jet actually picks up the fuel the jet is the start of the fuel flow to the air intake the jet restricts how much fuel is picked up

http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Carburetor.svg/639px-Carburetor.svg.png

[Tiggie]

cheers for that Stu, was very helpful.

I'm going to pull them apart again and recheck everything, make sure float height is in spec etc. I'm pretty sure that everything is clear. I'm tempted to thread some wire through every jet and take photos just to prove it

[Chrissb6]

Is the carb rubber mounted? This could be split hence the lack of vacuum just a thought

[Stu]

yeah double check that float height as if there isnt enough fuel in there it wont pick it up

I would be tempted to raise it really high so its full of fuel and possibly running out the overflow just to rule it out

the floats not sticking either is it?

[Guest Hodgy]

Like Stu says, check the fuel height in the float chamber, that gets my vote for being the culprit

[Tiggie]

i'll be refitting carb in morning now after giving it a bloody good seeing to. bad news is i've found a leak in one of the exhaust manifolds

not a visible hole but fuel was dripping from the seam, hunted in shed for some gun gum but looks like a trip to halfords is in order

[sliderglider]

how old is the fuel in it petrol does go off

[Stu]

how old is the fuel in it petrol does go off

 

as already mentioned its his daily ride it was working one day then the next no worky

[Tiggie]

i'm probably miles off and will probably give the experienced guys a good laugh but was wondering.....

would the leak in the manifold affect the vacuum enough to stop the engine drawing fuel from the carb?