450 won't start please help

[Nick]

Never been any problems jump starting them. On the 05's thats the only way we could get em going when it was below 30 degrees out. My 07 has always started even at 20 degrees.

[Oldcow]

I am having issues staring the bike when hot, not all the time, but often enough. The bike is running great other then that but its annoying when I stop, I have to let it cool down and then it starts. It will sometimes start if you turn the key off, kick it several times to burn off the gas, turn back on and away it goes. Today was different, I waited 5 minutes and it finally started with with the throttle wide open.
Any ideas?

[bergerhag]

I was tinkering a bit with ecu trim adjustments on my 05, and I got very similar problems to what you are describing. What I did to GET the problems was increasing the trim number from factory set '16' to new '29' to make it run a little richer. Did that because I thought it was running a little lean/hot. To accommodate the richer trim I adjusted the idle adjuster screw slightly, from a TPS readout of 5,7 to new readout 6.2 to make it idle cleanly.

With this new richer trim the bike was horrible to start when warm. Had to kick it out with ignition off several times. Later I went back to factory trim setting, but kept the new idle adjustment setting. Bike now idles a little higher than stock, but not too much. But as a bonus it has become very easy to start, both cold and warm. And yes, a lot easier to kick start too.

Before I did any changes I occasionally had warm start problem, but now it fires right up, I don't even have to wait for the fuel pump primer cycle to complete before hitting the e-button, just key on and hit the button at the same time.

Perhaps this can aid you in your diagnosis.

[Oldcow]

Originally Posted by bergerhag

I was tinkering a bit with ecu trim adjustments on my 05, and I got very similar problems to what you are describing. What I did to GET the problems was increasing the trim number from factory set '16' to new '29' to make it run a little richer. Did that because I thought it was running a little lean/hot. To accommodate the richer trim I adjusted the idle adjuster screw slightly, from a TPS readout of 5,7 to new readout 6.2 to make it idle cleanly.

With this new richer trim the bike was horrible to start when warm. Had to kick it out with ignition off several times. Later I went back to factory trim setting, but kept the new idle adjustment setting. Bike now idles a little higher than stock, but not too much. But as a bonus it has become very easy to start, both cold and warm. And yes, a lot easier to kick start too.

Before I did any changes I occasionally had warm start problem, but now it fires right up, I don't even have to wait for the fuel pump primer cycle to complete before hitting the e-button, just key on and hit the button at the same time.

Perhaps this can aid you in your diagnosis.

Are you suggesting that setting the idle up is what you think helped out? I am ready to try anything. My biggest concern is killing the battery and not being able to kick start it in the wilderness.

[bergerhag]

No, I was both thinking you're running to rich and need to open up the throttle a little.. Try reconnecting the blue/yellow wire under the tank, that'll put it in the lean map. If that gives you an easier warm start you need to get hold of the technoresearch VSTDS software.(or keep it on the lean map)

[stay_upright]

Check the thermostat - this went on my mates bike and was near impossible to start from cold. Was OK when hot though but yours may have failed the other way around.

There's a good chance you could buy a longer kickstart as well but to be honest if you've completely flattened the battery trying to start it then you have less chance with the kickstart - also the battery needs some juice to allow it to be kickstarted to prime the fuel pump I believe.

[bergerhag]

With the Techoresearch software it is possible to get a readout in degrees Centigrade from both air and water temperature sensors.

[GasGas]

I was always able to jump start mine very easily. It never started for shit with the kick though. The battery does need to be strong and cracking the throttle does help also.

[Jim Cook]

Sorry to intrude, but...
Just in case anyone is interested, I have the Magnetti Marelli MotorBike Diagnostic Program (including all the disks, and also loaded into a laptop).
It sure makes having a GasGas 4-stroke much easier to work on.

If anyone is interested in purchasing this, I would like to sell it.

Thanks,

Jim

[Oldcow]

Originally Posted by bergerhag

No, I was both thinking you're running to rich and need to open up the throttle a little.. Try reconnecting the blue/yellow wire under the tank, that'll put it in the lean map. If that gives you an easier warm start you need to get hold of the technoresearch VSTDS software.(or keep it on the lean map)

I am only good at basic maintenance on my bike so it looks like I will have to take it to the dealer as the problem is getting worst. Forgive my ignorance but what does the "technoresearch VSTDS software" do? and if I left those wires plugged in, the bike would not run as strong correct?
thanks