Clean carb, spark, air, valves but still non-starter?

[Piercee100]

A bloke at work has been having trouble with his scooter. he ran it out of petrol but apparently it's been running badly for the last hundred miles or so.

It has a nice fat spark and the carb float bowl is full of fuel but it still wont fire, despite turning over fine. I thought maybe the fuel needed to be bled through so squirted some easy start in the airbox to help fire it up and help the process along but it simply isnt interested. If the carb was blocked it would still let the easy start fumes reach the cylinder to create a bang?
Looking at the spark plug its dry as if no fuel is coming from the carb to the plug? Could this be a valve adjustment problem? If the valve has stuck closed it would stop fuel / fumes getting to the plug wouldnt it?

Any help appreciated as I seem to be stuck with a workmate who doesnt carry his own tools and not going away to deal with this himself!
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Rides: Honda H100a (Retired), VT500e (Sold), Kawasaki ZX400 (sold), Kawasaki GT550 (Sold), Suzuki Inazuma (Daily), Honda CD185t (Broken), LML Star 2t (Last run edition).

[mudcow007]

clean the jets in the carb

[Inked]

Have you tried putting a few drops of fuel down the plug holes an seeing if it starts?


Sometimes that's just enough to get an engine running again

[Piercee100]

So last night I cleaned the carb out for him, but it was already clean and the jets fine. I adjusted the valve clearances to 008 at the described in the owners manual. It has spark but the bastard still wont fire?
Neat fuel and carb cleaner do not seem to help even sprayed straight into the cylinder under the intake manifold. I cant get fuel into the spark plug hole as its in a bloomin aweful place. I will need to get a 12" long bit of hose and physically blow it in place
Next test will have to be a proper compression test since its not easy getting a finger over the spark plug hole due to the scooter's plastic body. I cant seem to find much evidence of fuel hitting the spark plug, which I thought a valve adjustment would cure? The cyclinder does get warm with some cranking so something is happening inside.

If compression is the problem, what could cause a sudden loss of compression? No evidence of smoke before its recent death so would rule out piston rings? The spark plug is secure and new so I know that's okay although had threads let go on me before but this one seems solid.
I think he's going to have to bite the bullet and book it in somewhere as this is hurting my head!

I'm guessing that the standard chinky side-stand switch would stop the spark plug sparking rather than stop something else happening?
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Rides: Honda H100a (Retired), VT500e (Sold), Kawasaki ZX400 (sold), Kawasaki GT550 (Sold), Suzuki Inazuma (Daily), Honda CD185t (Broken), LML Star 2t (Last run edition).

[devojunior]

2 or 4 stroke ?

what has it been doing wrong for last 100 miles ?

[Scotsman37]

Are you really sure the carb jets are clean because if you can't see light through the jet then its blocked!

[smegballs]

[Bunny Lingus]

Do you think it has an immobiliser?
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Bunny Lingus & The Flipside Faggots

[Piercee100]

No imobilisor. Apparently he's come off it a couple of times and has caused the side stand switch to have "issues" but again, testing that has proved inconclusive.

I'm taking the weekend off from thinking about it and my phone is off!
Weird that its stressing me out so much and its not even my scooter lol. It's just bugging me...
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Rides: Honda H100a (Retired), VT500e (Sold), Kawasaki ZX400 (sold), Kawasaki GT550 (Sold), Suzuki Inazuma (Daily), Honda CD185t (Broken), LML Star 2t (Last run edition).

[woll]

If it's getting a strong blue spark then I'd say it's a blocked jet in the carb.
If the spark isn't strong and blue then a problem on the ignition circuit is stopping it starting. Could need a new plug or a few mm off the ht lead to get it strong again.
Can't remember if you said whether the plug was getting wet or not. If it isn't get the carb cleaned properly. Wish I had a pound for every customer that told me the carb was clean on their quad when it wasn't. Completely strip the carb, blow cleaner through every hole in the body possible, get a small pot (lid off a spray can works well) put jets in and cover in carb cleaner leave to soak while cleaning the rest of the carb. After they have a soak blast with carb cleaner and make sure you can see light through them. Put carb back together and reset to factory settings the idle screw and mixture screw.
If you have a spark and a spotless carb then it starts to look like a timing problem. Quite common on the 250cc Honda engines to slip a tooth on the chain or even a few teeth. Sometimes they will start run like a sack, others won't do anything. Although when that happens the plug still gets wet.
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Current Bike- Suzuki DRZ400 SM K6
Previous bikes - Derbi Senda Xtreme50r, Honda CBR 125, Kawasaki ZZR 250, Yamaha DT125R, Suzuki Bandit 600, Gas gas ec 250, Honda CBR600FW
Damaged spleen, damaged kindey, 2 popped lungs, 2 broken ribs, broken face, broken wrist and 5 back fractures... remember kids walls hurt

[bypass2]

when he run out of petrol the diaphram the petrol tap maybe faulty. is the petrol tap working and petrol getting to the carb. also is it vacum feed.

[Nobby the Bastard]

I know it's unlikely, but is there a possibility that the spark is happening at the wrong time? Ignition timing out?
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[moonzoomer]

Possibly float level if the bike has been dropped, it takes very little to upset the float level.

[Nobby the Bastard]

[moonzoomer]

[moonzoomer]

[Nobby the Bastard]

[Bunny Lingus]

This sounds like a real deep biatch of fuctifino proportions
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Bunny Lingus & The Flipside Faggots