Wont Start!

[vanman1950]

Hi .....have 2012 250st which packed up at a trial few weeks ago when it would only start even when hot with choke and could not get it to tick over at all so took air box off and carb blasted jet and carb with air line plus carb cleaner but could not get carb and box back,real pig of a job so called on a friend to help who after some time managed to re-fit.

Sorry this is long winded but may lead to a clue?

When I picked up bike it started and ticked over even though filter was out.

Now went to start today (should be riding tomorrow) and no joy....good spark,new plug,fuel in carb any ideas please?

Thanks in advance......Pete.

[sirdabalot]

If the ignition circuit is giving a good blue spark, try the carb again, petrol on, lean the bike over till petrol comes out the overflow, choke on and kick. If no petrol overflows, fix that bit. If it does, after kicking see if plug is wet. If it is, could be ignition, these can give intermittent faults.

[vanman1950]

Thanks sirdabalot,I'll check that out today although I did loosen the float bowl and fuel came out so assume fuel is ok?

[vanman1950]

Hi sirdabalot,

could I have re-fitted the floats wrong therefore not filling float bowl?

Really trying to avoid the need to remove carb/airbox as such a task to re-fit!!!

I did try leaning bike as suggested and carb did not appear to overflow and plug was dry ish,I suppose it is possible that I have fitted the fuel line to carb at the wrong angle causing a kink in the pipe but was hoping as said to avoid removing carb/airbox.

[vanman1950]

Thanks oni nou I did remove the jets to blast them I think i'll go down the vaccum route next and see if that cures the problem.

[lineaway]

The 250 with the air box where the tank should be is a real bitch to get back together. The air boot is made for a Keihin, but the 250 has a Del Orto. Sherco made an odd rubber adapter that is offset to fit this carb. Sometimes it pops right on and other times it is a real pain.

To properly clean a carb, you have to take it completely apart to clean properly. The pilot circuit actually has to different inlet points. One in the center of the carb and one just in front of the slide. Both have to be clear. Make sure the choke circuit is clean at all points also.

[vanman1950]

Hi just wanted to say thanks to you all for your replies,now sorted it was the vacuum pipe that was the problem.

Must say it's great to have access to so much help at the touch of a button.

[stpauls]

Points:

The fuel pipes on the Sherco STs get brittle after a short while and can allow fuel to leak out and/or air to leak in on the suction side of the fuel pump.

Mine will not start if there is not ENOUGH fuel in the tank, although there may still be a bit still left in the tank and if I had not deliberately stopped it, the engine would have run on for some time.  I have to put a bit more fuel in and it will start again.