2007 Gg 250 Txt Pro - Hot Start Issues

[miner]

13 hours ago, Tr1AL said:

@miner The timing is fixed on the pro the woodruff key gives the position on the crank  and the pick up fixing plate gives no adjustment nor the stator plate. As you had this problem when you had the old ignition system fitted and now the brand new system is giving you similar results it may be better to look at things you did not replace,  maybe try a different carburettor and also decoke the head combustion chamber and crown of the piston then polish it to a mirror finish. Make sure your coolant hose from the cylinder head to the top of the radiator is not touching the bottom of the fuel tank and set your cooling fan to run permanently when the ambient temperature is 40 C etc by putting a thick copper wire from the earthing bolt at the top of the frame on the exhaust side then put a bullet connector of the correct size on that wire and plug it to the female ended wire that comes off the little black box that is held onto the fan shroud by a small pozi drive screw. That is of course if you are running a standard 2007 model position  thermostat fitted to the top right hand head of the rad and situated at the front side of the rad facing toward the front forks , also check your carbs float arms are set parallel to the edge of the carb body so that you have plenty of fuel in the bowl. There is still something that needs changing on your set up if you still have problems. starting and also kicking back , coked up piston and combustion chamber? . After all this buying a new ignition set up you have to keep going ,  it cannot be much of a big problem to solve the issue now. Regards Alan. 

Thanks Alan, a lot to unpick so I left it till I got home and onto my iPad… 

Didn’t think there was any movement in the pickup, not like they days of offset keys to add/remove advance for old school two stroke tuning. 🤓

Cylinder and piston were all deglazed and decoked when I did the water pump and again when I split the cases there, should be ok. 

Coolant hose should be ok but its a good point… will double check. 

Fan is standard 2007 and on its last legs… keep spraying lithium grease into it when its hot, its stopped squawking for now. On the watch list. No issues with spewing coolant with the current set point. 

Floats were just replaced, one was full of fuel. Not checked the arm setting as it was fine before but will have a look when playing with the jetting. 

Issue is only this one now… it was cutting out when hot. Rectifier showing signs of burning out from the inside out. 

I think it is something fairly niggly/poxy that’s causing it… will keep digging. 🦾

[miner]

1 hour ago, lemur said:

"Stator looks OK, noting obvious."  Are you testing the stator coils with test equipment or by eye 🤔 looking at coils tells you nothing unless they are burnt to a crisp, you can meter test coils for resistance or you can oscilloscope test the AC output and confirm it is fully functional.

Sparkplug cap and wire has been changed?  They don't last forever.

"Plug is gapped ok, looks ok, not fouled. "  Sometimes the insulation is cracked and the defective plugs will spark way up inside the plug body and not at the electrode gap.  Try another new plug.

If you can't narrow it down to being either a carburetor or ignition issue there is not much anyone here can help you with.  Do you have access to another GasGas TXT you can swap parts with, that is what a dealer would do to eliminate the carburetor as being your problem.  Parts swap is also the only way you can reasonably test the ignition module.

Parts swap not an option as they are few and far between here… like hens teeth unfortunately. 

Stator looks OK = visual no signs of damage or overheating, burn up. I’ll have another look on the Hell Team’s website to see if there’s useful values to re-test against. I went through the ignition system before and diagnosed that the Coil/CDI and Rectifier was the problem. Bike has stopped cutting out when hot since, just the hot starting issue persists. 

Coil Wire = New with the CDI/Coil and integral to it. 

Plug Cap = Tested it but without a proper reference value it’s hard to tell. Checked against the values in my KTM manual (two stroke, NGK cap), it looked ok. No Visible defects. Easy to swap though. 

Plug = I’ve tried swapping them about with a couple I had around and same issue. It’s an iridium plug and not that old, within the specified hours. I’ve ordered some more too. 

I’ve turned it inside out in the process of troubleshooting it… KTMs are much easier, they give you the test resistance values for everything, so you can get down to the extents of primary and secondary coil failures. 

I think its a carburation issue… I’m going to swap the jets and see how it goes. When it starts its often when you get just the right amount of throttle… but wanted to work backwards through it again in case I had missed anything obvious. 

Will order a plug cap since I’ve changed the CDI/Coil.