Hi all, i'm having a bit of trouble with my Yamaha XS 250 Custom 1980. It keeps on firing on one cylinder and i do not know why? I have changed the one ignition coil, the condenser, the pickups and set them to a measurement of 0.35mm but i'm still having trouble with it. Can someone please help me as this is the only problem i'm having that's stopping me from getting it on the road. Many thanks; Kyle

you say you changed the pickups and condenser? you can't have a condenser if you have electronic ignition!

not a lot of info to go on, has the bike been standing, did you drain the fuel?

is the battery fully charged?

have you an inline fuel filter?

are your fuses tight and not corroded?

spark plugs ok?

compression ok?

timing ok?

etc etc........

Sorry, not pickup, points i mean.

Not sure about it being stood. Apparently the geeza who i brought it off said he had ridden it before and saying he was going to mot it for the summer.

Put new fuel in it.

Battery isn't charged but jumped it off another battery to start it.

Yes it has an inline fuel filter.

Its had a new fuse box put in it and all new fuses are in it.

I put in two new spark plugs about 3/4 days ago.

The compression is quite soft to kick at times.

And the timing is in too bud.

are you getting sparks from the plugs out of the engine or is it just dead?

Yeah i am getting sparks from both plugs. Just it starts up good, but when you go to ride it, its flat until it kicks in which then seems it runs on two cylinders about half way down the road?

sounds like the pilot circuit is blocked in the carbs.

With modern fuel, gumming of the little passages is very easy to do if you don't drain the bowls for storage. Also the float levels could be out too!

How about setting off from halfway down the road?

sounds like the pilot circuit is blocked in the carbs.

With modern fuel, gumming of the little passages is very easy to do if you don't drain the bowls for storage. Also the float levels could be out too!

Ah right, could you give me a few pointers on how i may sort this out then please? If that's okay by the way...

best to head over to xs400.com where its been talked to death

Ah it's finally done! It was that some div who had the bike before us had put the carb float and washer back to front instead of the needle in first and then the washer, now she's running at last! Aha but thank you for narrowing it down to the carb mate! Thanks

no probs