confusion about fuel/oil ratio on TXT pro 125

[RMJay84]

Hi everyone,

I'm just after a 2nd opinion about the fuel/oil ratio for my gas gas 125.

The dealer said 80:1 (125ml in 10L), which is what I'm using with fully synthetic Castrol TTS.

I went for a 6km ride of just single trail probably 4-5th gear stuff with sustained rpm and my bike became really really smokey, like nothing I'd ever seen before. After stopping, the smoke continued to trail out of the pipe for about 5 minutes.

I started it back up and started playing on logs and obstacles again the excess smoke went away

The afternoon was probably around 25C

Could this be the engine getting too hot during sustained rpm and burning the oil? Improperly mixed fuel/oil sitting low in the tank/carb? Incorrect fuel/oil ratio? Or should I try a different oil?

Never seen anything like this happen on a 2-stroke, and never owned a trials bike before either, so any suggestions would be much appreciated :)

[David Lahey]

Its just oil and gunk burning inside the exhaust because you got the insides of the exhaust system hot enough. Normal to see that when ridden like you did after being used at low speeds for a while.
If it gets too wild inside the exhaust, it is possible to melt the aluminium parts of the exhaust. The gunk can/should be cleaned out periodically if you want to avoid it happening
While it is possible to overheat a liquid cooled trials motor, your situation doesn't sound like the engine getting too hot.

[David Lahey]

sorry there was another question - yes TTS at 80:1 should be OK

[RMJay84]

Ah that's great to hear thank you very much :)

[Gary B]

RMjay84,
Totally agree with David's points.
I've had Gas Gas bikes since 1996 (many of them) and currently on a 2014 280 racing.
I have always run them on 80:1 once run in.
I've had the smoky exhaust issues a few times but only after a long hard trail ride.
Never had smoky exhaust when just doing normal Trials work.

I've just got my youngest son a 2015 Gas Gas 125 Racing and it's bloody fantastic.
We have had 2 other 125 Gassers thru the stable over the years & the 2015 model is a huge jump forward.

Hope you enjoy yours.
Cheers,

[RMJay84]

That's awesome Gary :)