when i start it up cold its runs sweet as a nut, but as it starts to warm up, it starts to run a bit lumpy. The warmer it gets the worse it runs, to the point where it will just about tick over, if i try to open the throttle even a tiny bit it dies, shut it before the engine stops and it will go back to tick over, just about. Now I've changed the head gas kit (needed changing anyway, coolant leaking from it and signs of compression escape, once removed so this was looking good as, maybe the cause of my problem) and i had the head checked by an engineer not warped, i also replaced the intake rubbers, fuel filter, spark plugs and another set of good clean low mileage carbs. Air filter looks new, oil is only few hundred miles old, spark looks good yet when i started it up after rebuilding it, no change, it did exactly what it did before. So back to square one and running out of options. This is also starting to get expensive. Has any one had any thing similar happen to them? HELP!!!!
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Got a problem with my Yamaha 600 Fazer, can any one help?
- Thread starter grant l
- Start date
True Conservative
New member
When it is cold are you using choke? If so as it warms up and choke is reduced you are adding more air than fuel. It sounds like a Carb problem.....Rebuild it.
Check timing and timing set
Check timing and timing set
It's a fuel emulsion problem
Either the needles are not being drawn up out of the emulsion tubes and the mixture is weakening with excess air. Or the holes in the emulsion tubes are blocked or the main jet is partially blocked.
Could be the diaphragms on the CV slides or worse.
Just because the carbs you bought are low mileage doesn't mean they are good. There could also be rubbish and crud that has got from the tank into the rest of the system. Check also the fuel pump is working correctly.
Either the needles are not being drawn up out of the emulsion tubes and the mixture is weakening with excess air. Or the holes in the emulsion tubes are blocked or the main jet is partially blocked.
Could be the diaphragms on the CV slides or worse.
Just because the carbs you bought are low mileage doesn't mean they are good. There could also be rubbish and crud that has got from the tank into the rest of the system. Check also the fuel pump is working correctly.