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GasGas Txt 280 cylinder head orings blown

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Hi there, Following catastrophic blowout of cylinder head O rings on my 2001 TXT 280, I have replaced O rings, drained and flushed what was left of coolant, stripped and cleaned carb and air filter and reassembled with O rings correctly seated and correct torque settings. Now it doesn't start. On first kick it tries for a couple of fires then dies, then nothing. Spark plug and piston head covered in chocolate-milk-y gunk. To me that suggests the head is warped as fuel is getting through and mixing with coolant. I am happy to have a go flattening the cylinder head myself before splashing out on a new one but before I do, anyone have any ideas of anything else I need to check? Thanks in advance

Maybe it's just coolant that was still sitting in the crankcase after the o rings failed and when you tried starting it after fitting the new o rings, the coolant was blown up out of the crankcase and onto the piston and spark plug

  • Author

Thanks, good suggestion. Any ideas how to remove any coolant left in the crank case? Thanks

 

Is fan / thermostat working ??.  Fan rectifier unit a common failure, Bad earth causes it to fail / melt , & prevents fan working, with subsequent boiling over. You might have an oil / water emulsion in the crankcase, & oil seals may have suffered.  

Well documented in forums section. Been there before unfortunately. Not that unusual for a GG of this age. 

Milky Oil :  Drain down, take off the outer case & clean with fuel as best you can.  Re instate & carry out a flushing run for a few minutes with  ATF or thin Trans oil, then drain. replenish.. Generally comes good fairly quickly. You might get lucky with new head O rings, but another very common cause of water in the trans is water pump lipseal failure (Seal wears out & also makes a groove in the impeller shaft. You need to change both)

  • Author

Much obliged, fan is working. It is definitely a case of oil and water mixing where they shouldn't, cylinder head being warped is my best guess. If there is any water in the crankcase is there a way of removing without taking the crankcase cover off?

 

Edited by gasgasgasgas

14 minutes ago, gasgasgasgas said:

Much obliged, fan is working. It is definitely a case of oil and water mixing where they shouldn't, cylinder head being warped is my best guess. If there is any water in the crankcase is there a way of removing without taking the crankcase cover off?

 

Remove fuel tank and spark plug, turn bike upside down and operate kick start to pump water through. You might loose a little gearbox oil while doing this so check when upright.

Txt editions have a crank case bottom end drain plug for this. Remove the skid plate and the plug is on the bottom of the big end. Wish others did this...

—Biff

15 minutes ago, biffsgasgas said:

Txt editions have a crank case bottom end drain plug for this. Remove the skid plate and the plug is on the bottom of the big end. Wish others did this...

—Biff

But getting the skid plate back on can be a real pain, especially on a older bike. 

  • Author

Excellent thought...will check asap before going any further! Many thanks to all

 

  • 2 weeks later...
On 9/28/2019 at 9:30 AM, doctorchopper said:

But getting the skid plate back on can be a real pain, especially on a older bike. 

That just means its time to re-arch the pan. 
 

—Biff

16 hours ago, biffsgasgas said:

That just means its time to re-arch the pan. 
 

—Biff

good excuse for the 10 pound sledge.................................

yes, I have done so for the Old BAGG

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