[GasGas txt 300, 2017, excessive smoke when hot]

1 hour ago, bumpy_ltd said:

Yes far too much oil. You want 60ml of 2t per 5 litres of petrol. I use Putoline mx9 which seems to burn better than others Ive tried. Also super unleaded fuel from either BP or Shell makes a difference.

 

Best case scenario is that all of your silencer packing is soaked in oil which is why it smokes when hot. Worst case is crank seal has gone. If it was the crank seal then you could tell from the smell of the burning oil and your gearbox oil would be low. If thats ok then personally Id go a few miles down the road on it then (when cools down) repack the silencer. Trialendurodirect.com do this which is dead easy: https://trialendurodirect.com/product/expanding-exhaust-packing/ and this which in my view is better but a lot more involved: https://trialendurodirect.com/product/silent-sport-exhaust-packing/ 

Thanks again, what a friendly and helpful bunch you are! I will have a tinker with it and see what conclusion i come to, then will report back.

Very intrigued that a few of you suggest to lean out the oil to fuel ratio, against the manuals recommendation! 

[GasGas txt 300, 2017, excessive smoke when hot]

1 hour ago, zippy said:

do you know what the previous owners were running for an premix ratio?

Possible they were running a high(er) amount of oil which would foul the packing sooner than 80:1

OR it's possible the crankshaft seal has gone bad and is sucking in gearbox oil.

 

I am running it at 50:1 as that is what is stated in the manual online.. is that too rich?

[GasGas txt 300, 2017, excessive smoke when hot]

Ok I will try re packing the silencer. 
it’s only 2 years old and the last (2nd owner) only road it 4 times in 6 months. So does seem a little odd that the packing has broken down? 

[GasGas txt 300, 2017, excessive smoke when hot]

Awesome thanks for all of your comments, I would like to be able to ride it for 30 minutes non stop if possible. Is that not ok on a trials bike? 
 

I come from a motocross back ground, but have bought this for a bit of fun and mid week fitness etc. Wouldn’t mind entering a couple of local comps too! 

[GasGas txt 300, 2017, excessive smoke when hot]

I have just bought a GasGas txt 300. 
it runs fine and has lots of compression etc. When riding it on a loop on the woods for 15 minutes or so and getting it nice and hot, it starts smoking excessively a blueish smoke. If I stop and let it cool for 5 minutes the smoke stops, until I get it hot again. 
 

I'm thinking (and hoping) this might be excess oil built up in the exhaust, has anyone had any experience of this? 
 

The bike gets warm to the point where the fan goes on for a few seconds here and there when riding, but I’m pretty sure it’s not over heating.