My 2002 250 txt Pro has a weird problem that is driving me mad !

The engine will start & run normally, but after a short period - (within 30 minutes) the engine will die and will not fire again for several hours !

There no spluttering or misfire - its like its run out of fuel, but it hasn't.

So far I've:

Cleaned carb & filters.

Carb float needle does not appear to stick

No air leaks around read valve block etc

replaced the kill switch

checked spark - seems O.K.

Could it be the the Crank seal on the flywheel side ?

Can us fit these without splitting the crank ?

I am arranging to borrow an ignition to rule that out.

Anyone had similar problems?

Thanks in advance

Edited May 17, 201016 yr by mccarro

Sounds like the gas tank vent is blocked. Gas out air in. Could also be a bad fuel petcock.

Let it happen then pull the spark plug. If it's wet, its electrical. If its dry, then it's running out of fuel.

When and engine is running out of fuel - there is usually a brief period where the engine starts to run lean and run a bit faster as the mixture becomes lean. You can turn your petcock off and see what this would feel and sound like while riding - then if the bike behaves the same way when it stops running you will know what it sounds like when the carb stops getting fuel. When the engine stops you could take out the spark plug, place it back into the electric cap and ground the plug against the engine and kick it over and see if it has any spark. While the plug is out you could place a small amount of fuel mix into the cylinder and see if the engine will restart for a brief period. If the engine is running out of fuel you should loosen the fuel cap and see if the fuel flows and the engine will restart. You could also take the fuel line off at the carb and turn the fuel flow on and see how long the fuel will flow out of the tank to confirm that you have good fuel flow from the tank. The fuel should flow in a steady stream until the tank is empty.

Your problem does not sound like a crank seal to me - minor air leaks usually make the engine run lean and the engine races or idles weird.

Checked again tonight and it appears the spark is intermittent.

Plug & cap are new -

I know sod-all about electrics - should I replace the ignition the coil, or both ?

Thanks for replies

Hello

I'm no expert - starting again after 7 year layoff - but .......

Looks like you may be into the "world of electrics" - could be stator or CDI unit or coil. More likely CDI or coil.

Had problem in 2001 which was CDI unit on near new bike. In my case bike wouldn't even start despite "crappy spark"

Fortunately my son had same bike so swapped bits across to find problem. CDI unit replaced under warranty.

Have you checked wiring for damage and made sure all connections are clean. Costs nothing but time and is always my first check if any electrical probs.

FYI - in 1970,s had an OSSA MAR which had problem of running for 60 mins then stopping for no reason. No spark when tested. Left for 30 mins tested again and spark OK. Miraculously working again without doing anything but wait.. Fired up and off again for 30 mins. Then stop again etc. etc . Turned out to be coil - but from memory I think that Motoplat system had some 'control electronics' built into coil.

david

For info :

I replaced the ignition yesterday and the problem has gone.

Thanks for all replies