cactusjack Posted March 15, 2014 Report Share Posted March 15, 2014 So the other day I bought a bike that was sold to me as a 2009 TXT Pro 300. The bike had a hard life, I could see that when I looked at it, and I am a mechanic, but on initial inspection and with a brief ride all appeared ok. Geez, was I wrong. Firstly, when I test rode, for a few minutes only, the motor seemed quiet and ok. I got the bike home and rode it the next day for 20 minutes or so and as it got hotter it got noisier. A real tappy, clicky type noise. Something I had not heard in my limited time with 2T's. I googled my ass off and found that they are a fairly noisy motor. Still I am pretty sure at that point that this wasn't the normal Gasser noises. The night I brought it home I also thought I would check out the chassis number and it appears that it is actually a 250 that has had a 300 barrel put on it. So after being sold a TXT Pro 300, I had actually bought a 250. Kicking myself for not researching the chassis number beforehand. I rode it some more and the gearbox oil came up very milky looking. Next problem............ I am not happy at this stage and am thinking the worst about the bike. He had said he had just done the water pump, but it seemed a little too much milk for it to be residual water in the gearbox. I am getting more and more annoyed at myself for being a bit hasty on the purchase and was wishing there was concourse for return. Unfortunately though, there isn't. I drained the oil, which came out not too milky in the end, and seems to show less water problems than originally thought. Some silver lining starting to appear. Then I remove the oil filler plug and it is cross threaded like a *******. What a butcher that I bought this off. I remove the water pump and it all looks good, no water in the back of it, so that at least confirms residual water in the gearbox causing initial milkyness. I have since removed the top end and it needs a piston and rings, as the rings were stuck fast in the piston. Maybe a cause of the noise I was hearing. Also the exhaust header was loose, another possible cause of the sound I heard, and this being the most likely cause, as the sound wasn't consistent or uniform like you would expect from a bearing sound. I have put it down to these two things. The bore is in ok condition, but will need a hone. A piston measurement confirms it is 300cc. So it would seem it is a 250 that has had a 300 barrel put on it. The big end bearing is tight and shows no signs of any wear. This is also a positive. The Kickstart gear is missing 2 teeth and the others are grinding away, which explains the metal shavings on the magnetic filler plug. The carby needs a clean as it is leaking when the fuel is left on. So that is the tale of my woes and bad start as a Gas Gas owner. I think things aren't as bad as I first thought, but there is still a few dollars to spend to bring it to a rideable state. I hope it holds up as a great ride once I have finished working on it. Thanks for listening......... 2 Quote Link to comment Share on other sites More sharing options...
baldilocks Posted March 15, 2014 Report Share Posted March 15, 2014 Piston slap gets worse as the bike warms up. If it is this which is caused by a worn bore / piston it will be most noticble at low rpm. Ie blip the throttle it goes away as it returns to tick over you hear a rattle. In my experience every time you fit a new piston to a worn bore you end up back where you started after a couple of rides. Spend the extra and get the cylinder re coated to match your new piston and it will last a couple of years. Quote Link to comment Share on other sites More sharing options...
lineaway Posted March 15, 2014 Report Share Posted March 15, 2014 Bright side is it`s new enough that you can buy just the starter pawl and idler gear. Make sure the missing teeth did not travel and get stuck in the large primary gear. Just a little metal in between the teeth can make a hell of a racket! Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted March 15, 2014 Report Share Posted March 15, 2014 Milky oil is an easy and cheap fix pretty sure 250 and 300 are same bottom end anyway? Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted March 15, 2014 Report Share Posted March 15, 2014 most likely a water pump seal. Quote Link to comment Share on other sites More sharing options...
baldilocks Posted March 15, 2014 Report Share Posted March 15, 2014 Dabster is right bottom half is the same 250 / 280 / 300. Quote Link to comment Share on other sites More sharing options...
guys Posted March 15, 2014 Report Share Posted March 15, 2014 Been there, done that Quote Link to comment Share on other sites More sharing options...
huski Posted March 15, 2014 Report Share Posted March 15, 2014 Doesn't sound too bad £300 should fix it,250/300 are identical apart from top end.Kickstart assembly is thus strained with the bigger piston,not too bad to replace makesure no bits have embedded in the clutch/crankshaft gears,a tiny bit makes it knock like you wouldnt believe.You sometimes needs magnyfying glass to see it.The clutch normally rattles till you pull it in,Worth spending a bit of money and time on,it's not hugely different from a new one Quote Link to comment Share on other sites More sharing options...
cactusjack Posted March 15, 2014 Author Report Share Posted March 15, 2014 Thanks guys. I will measure up the barrel after giving it a good hone and make sure the clearances will be ok with the new piston, check my ring gap etc. If all measures up ok I will not bother re-coating the barrel. A Wossner piston will cost me around $140 in 79.98mm. I need to price up gaskets etc, but they should be around the same money I would think. The kickstart gear may be a little expensive, but after that it'll be happy riding days all over again. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted March 16, 2014 Report Share Posted March 16, 2014 You might get a second hand gear from allen spares. Quote Link to comment Share on other sites More sharing options...
cactusjack Posted March 16, 2014 Author Report Share Posted March 16, 2014 I'll check it out, thanks Dabster. Quote Link to comment Share on other sites More sharing options...
nelly1 Posted March 16, 2014 Report Share Posted March 16, 2014 good luck mate ive done the same Quote Link to comment Share on other sites More sharing options...
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