Yamaha XJ650 (1983) seems to be running out of gas each time I start up

[Chasletini]

Hi chaps. I just joined. I have a 1983 Yamaha XJ 650 Custom, a very pretty bike. I have run it for a couple of years (one full service in that time) after buying it on Ebay. Three weeks ago I couldn't start it - don't know why. A guy said take off the plugs and burn them off and try again so I did. Still wouldn't start. Then suddenly it burst into life and reved very high (I wasn't holding the throttle, the other guy was and he had it on full twist). Then it died very suddenly. I left the bik for a day and then the next day started it 100% fine. But it died after abou 2 miles of ride, as if the gas had run out. The day after I tried it again and the same thing happened. I tried it a few more times (give it 24 rest, then it sttarts fine, then it dies). So I took off the carbs and they look clean and good and re-seated them; I took out the air filter and it was very oily (could this have been the effect of the very high revving occassion?) so currently the bike doesn't have an air filter until I get a replacement. I have run it with the petcock on Prime to see what would happpen. But each and every time I get the same behaviour: after a 24 hour rest it starts and runs fine for a mile or so and then dies as if it is running out of gas. Is there any kind soul out there who can suggest a solution? Cheers, from England!

[Aussie Steve]

Which bit of England?...I'm from Bradistan...sorry that should be Bradford West Yorks originaly..........anyway onto the bike Are the plugs wet? If so it could be a sunken float and or the float height needs attention causing a too rich mix.

The air filter is oily probably because it is old...not from the full throttle. If your air filter is so crappy then you should look at all the filters including the fuel valve filter in the tank. This involves removal of the fuel valve so make sure there is little or no fuel in the tank before you pull it off.

I usually run the tank low and then remove it and use blocks of wood to tilt the tank away from the valve. If this is OK then I would run some carb cleaner through to make sure all the jets etc are clear.

This sounds like a float needle is sticking so further examination in that dept may find the cause.

Good luck

[Easy Rider]

Originally Posted by Chasletini

after a 24 hour rest it starts and runs fine for a mile or so and then dies as if it is running out of gas. Is there any kind soul out there who can suggest a solution? Cheers, from England!

In order of probability:

Restricted fuel flow.....petcock, screen in tank, plugged hose, float stuck closed.

Tank vent plugged. Vacume in tank stops flow.

An electrical component gives out when it gets warm/hot. (long shot)

Pip, pip from America.