christopherd Posted January 4, 2012 Report Share Posted January 4, 2012 Hello everyone, I have been reading for a few months and now I could do with a little help..... I have a Gasgas txt pro 280 2005. While out the other day the bike started to run rough and lost power then cut out :-( It was getting dark so I let it cool down then gave it a kick and it started and I managed to limp home :-) The next morning I went to take a look see and the gearbox is full of coolant :-( I think it could be the water pump seal but while I am okay with the tools I have never had a two stroke before and never done any work on them. I dropped the oil (and coolant) from the gearbox and took the water pump off, I have not stripped the water pump yet. Any Ideas ? What else could be amiss? Thanks, Quote Link to comment Share on other sites More sharing options...
paul w Posted January 5, 2012 Report Share Posted January 5, 2012 its the lost power and cut out bit you need to worry about. is sounds like it may have siezed the piston in the barrel. i would strip it down for inspection. Quote Link to comment Share on other sites More sharing options...
jse Posted January 5, 2012 Report Share Posted January 5, 2012 Hello everyone, I have been reading for a few months and now I could do with a little help..... I have a Gasgas txt pro 280 2005. While out the other day the bike started to run rough and lost power then cut out :-( It was getting dark so I let it cool down then gave it a kick and it started and I managed to limp home :-) The next morning I went to take a look see and the gearbox is full of coolant :-( I think it could be the water pump seal but while I am okay with the tools I have never had a two stroke before and never done any work on them. I dropped the oil (and coolant) from the gearbox and took the water pump off, I have not stripped the water pump yet. Any Ideas ? What else could be amiss? Thanks, My first guess would be a damaged inner o-ring in the head, which would allow coolant into the engine and cause loss of power and cutting out. The coolant in the trans could be coincidental to the o-ring problem but also could be caused by a crimped radiator cap overflow tube, which would force coolant (due to excessive pressure) past an otherwise good W/P seal. Jon Quote Link to comment Share on other sites More sharing options...
christopherd Posted January 5, 2012 Author Report Share Posted January 5, 2012 My first guess would be a damaged inner o-ring in the head, which would allow coolant into the engine and cause loss of power and cutting out. The coolant in the trans could be coincidental to the o-ring problem but also could be caused by a crimped radiator cap overflow tube, which would force coolant (due to excessive pressure) past an otherwise good W/P seal. Jon Inner o-ring? so head off and have a look? Quote Link to comment Share on other sites More sharing options...
jse Posted January 5, 2012 Report Share Posted January 5, 2012 Inner o-ring? so head off and have a look? When diagnosing problems, always start with the more simple, less invasive things. Make sure the overflow tube is not crimped. If the tube is routed over the crossbrace, the tank will squash it, allowing excess pressure to build up in the cooling system and force coolant past the W/P seal lips. This could save rebuilding the W/P. What type of sparkplug are you using and what does it look like when you take it out? If you can give an idea of what the engine running conditions were when you shut it off really helps to intrepret the plug condition. Jon Quote Link to comment Share on other sites More sharing options...
christopherd Posted January 5, 2012 Author Report Share Posted January 5, 2012 When diagnosing problems, always start with the more simple, less invasive things. Make sure the overflow tube is not crimped. If the tube is routed over the crossbrace, the tank will squash it, allowing excess pressure to build up in the cooling system and force coolant past the W/P seal lips. This could save rebuilding the W/P. What type of sparkplug are you using and what does it look like when you take it out? If you can give an idea of what the engine running conditions were when you shut it off really helps to intrepret the plug condition. Jon It was running really rought and making no power and I could feel it cutting out with zero throttle but it would run with a bit of gas on. when I shut the throttle it would stop after a second or so. The plug looks okay light brownish with a bit of white not the full white out I was expecting. Quote Link to comment Share on other sites More sharing options...
jse Posted January 5, 2012 Report Share Posted January 5, 2012 It was running really rought and making no power and I could feel it cutting out with zero throttle but it would run with a bit of gas on. when I shut the throttle it would stop after a second or so. The plug looks okay light brownish with a bit of white not the full white out I was expecting. Light brown is good. If it's coolant leakage, you should see small droplets down inside. Did you drain the carb any try fresh premix and a new plug? Jon Quote Link to comment Share on other sites More sharing options...
christopherd Posted January 5, 2012 Author Report Share Posted January 5, 2012 Light brown is good. If it's coolant leakage, you should see small droplets down inside. Did you drain the carb any try fresh premix and a new plug? Jon No I did not drain the carb or put any fresh premix in. Right the water pump is apart and there is a small tear in the seal (I can't imagine all the coolant getting through there as quick as that) Anyway the head if off, the O rings feel a bit hard and were stuck to the barrel top and did not come away in the grooves in the head. There are dropplets of coolant in the grooves in the head. There is a mark on the forward side of the barrel bore :-( How do you evaluate the need for a re-plate? I will order the full W/P overhaul kit( Quote Link to comment Share on other sites More sharing options...
jse Posted January 6, 2012 Report Share Posted January 6, 2012 No I did not drain the carb or put any fresh premix in. Right the water pump is apart and there is a small tear in the seal (I can't imagine all the coolant getting through there as quick as that) Anyway the head if off, the O rings feel a bit hard and were stuck to the barrel top and did not come away in the grooves in the head. There are dropplets of coolant in the grooves in the head. There is a mark on the forward side of the barrel bore :-( How do you evaluate the need for a re-plate? I will order the full W/P overhaul kit( Quote Link to comment Share on other sites More sharing options...
copemech Posted January 6, 2012 Report Share Posted January 6, 2012 (edited) This makes me wonder just how low the coolant was in this thing and how much came out on disassembly? If it did get hot and sieze a piston, it may well have scored a cyl a bit, yet this is not always the end of things, yet it may rattle a bit, maybe not? Time will tell. Hard to say without pics and more info, hope he is on the right track here. As in Jon's statement, but if the piston ali transfer is just stuck to the cyl wall, then there are ways to clean it up and the bore may be ok. A bit of cleanup work and a fresh piston and you are good to go! This is where you may require a first hand evaluation from someone experienced. Edited January 6, 2012 by copemech Quote Link to comment Share on other sites More sharing options...
christopherd Posted January 6, 2012 Author Report Share Posted January 6, 2012 This makes me wonder just how low the coolant was in this thing and how much came out on disassembly? If it did get hot and sieze a piston, it may well have scored a cyl a bit, yet this is not always the end of things, yet it may rattle a bit, maybe not? Time will tell. Hard to say without pics and more info, hope he is on the right track here. As in Jon's statement, but if the piston ali transfer is just stuck to the cyl wall, then there are ways to clean it up and the bore may be ok. A bit of cleanup work and a fresh piston and you are good to go! This is where you may require a first hand evaluation from someone experienced. The plating on the bore has to be harder than the piston or is it? Do you guys think the mark on the bore is meterial from the piston rather than removal of the plating? I am thinking that I could give it a rub with some scotchbrite ? I will try and post a picture later tonight. What will the torque setting be for the head bolts? Thanks, Quote Link to comment Share on other sites More sharing options...
christopherd Posted January 6, 2012 Author Report Share Posted January 6, 2012 Quote Link to comment Share on other sites More sharing options...
christopherd Posted January 6, 2012 Author Report Share Posted January 6, 2012 Quote Link to comment Share on other sites More sharing options...
jse Posted January 7, 2012 Report Share Posted January 7, 2012 (edited) The plating on the bore has to be harder than the piston or is it? Do you guys think the mark on the bore is meterial from the piston rather than removal of the plating? I am thinking that I could give it a rub with some scotchbrite ? I will try and post a picture later tonight. What will the torque setting be for the head bolts? Thanks, The grey cast plug looks like it was run in a cylinder than had coolant in the combustion chamber. The plating is somewhat harder than the piston so pistons wear faster than the bore. The bore is plated with very fine Silicon Carbide particles imbedded in a Nickel matrix. The pistons also contain Silicon Carbide, usually around 10-17%. So, you have a ceramic coating in the bore and ceramic in the piston. It's difficult to tell from the photo, but if it's piston material, you may be able to remove it with Muriatic Acid (used in swimming pool care). Obviously you should treat Muriatic with the same respect you would any strong acid and take appropriate safety steps. Scotchbrite probably will not remove it. You could try some 200-300 grit wet/dry sandpaper and water to do it but be careful to only remove the piston material. 11.5-13 Nm is the torque setting for the head capscrews. Jon Edited January 7, 2012 by JSE Quote Link to comment Share on other sites More sharing options...
copemech Posted January 7, 2012 Report Share Posted January 7, 2012 Pic is nor great, but I would say first thing you should do is put the lid back on and go powerwash things to get rid of the dirt so you can pull the cyl! It does appear to have ali transfer from the piston, so you will likelt find the piston looks worse than the bore. New one is indicated here! The trick to using the muratic acid is to carefully aply it using an eye dropper or such only on the specific area and let eat away the ali a bit. A bit of agitation with the scotchbrite is good, then wipe with a paper towel and re-apply to let it work again. Takes patience! Gloves required! Rinse nearby! Hopefully you find no pitting in the plated surface, should be smooth running a fingernail accross with no snags when done. None of this is reccomended for amatures, yet it can be done! Quote Link to comment Share on other sites More sharing options...
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